ECE 477 Final Report Spring 2005 - College of …...ECE 477 Final Report Spring 2005 -iii- TABLE OF CONTENTS Abstract 1 1.0 Project Overview and Block Diagram 2 2.0 Team Success Criteria

ECE 477 Final Report Spring 2005

Team Code Name: __GROVER__________________________________ Team ID: __7___ Team Members (#1 is Team Leader): #1: Joel Stubbs Signature: ____________________ Date: _________ #2: Andrew Parcel Signature: ____________________ Date: _________ #3: Stan Miller Signature: ____________________ Date: _________ #4: Edwin Tjandranegara Signature: ____________________ Date: _________


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REPORT EVALUATION

Component/Criterion Score Multiplier Points

Abstract 0 1 2 3 4 5 6 7 8 9 10 X 1

Project Overview and Block Diagram 0 1 2 3 4 5 6 7 8 9 10 X 2

Team Success Criteria/Fulfillment 0 1 2 3 4 5 6 7 8 9 10 X 2

Constraint Analysis/Component Selection 0 1 2 3 4 5 6 7 8 9 10 X 2

Patent Liability Analysis 0 1 2 3 4 5 6 7 8 9 10 X 2

Reliability and Safety Analysis 0 1 2 3 4 5 6 7 8 9 10 X 2

Ethical/Environmental Impact Analysis 0 1 2 3 4 5 6 7 8 9 10 X 2

Packaging Design Considerations 0 1 2 3 4 5 6 7 8 9 10 X 2

Schematic Design Considerations 0 1 2 3 4 5 6 7 8 9 10 X 2

PCB Layout Design Considerations 0 1 2 3 4 5 6 7 8 9 10 X 2

Software Design Considerations 0 1 2 3 4 5 6 7 8 9 10 X 2

Version 2 Changes 0 1 2 3 4 5 6 7 8 9 10 X 1

Summary and Conclusions 0 1 2 3 4 5 6 7 8 9 10 X 1

References 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix A: Individual Contributions 0 1 2 3 4 5 6 7 8 9 10 X 4

Appendix B: Packaging 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix C: Schematic 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix D: Top & Bottom Copper 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix E: Parts List Spreadsheet 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix F: Software Listing 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix G: User Manual 0 1 2 3 4 5 6 7 8 9 10 X 2

Appendix H: FMECA Worksheet 0 1 2 3 4 5 6 7 8 9 10 X 2

Technical Writing Style 0 1 2 3 4 5 6 7 8 9 10 X 5

CD of Website Image and Reports/Poster 0 1 2 3 4 5 6 7 8 9 10 X 2

TOTAL

Comments:


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TABLE OF CONTENTS

Abstract 1 1.0 Project Overview and Block Diagram 2 2.0 Team Success Criteria and Fulfillment 4 3.0 Constraint Analysis and Component Selection 5 4.0 Patent Liability Analysis 12 5.0 Reliability and Safety Analysis 17 6.0 Ethical and Environmental Impact Analysis 25 7.0 Packaging Design Considerations 29 8.0 Schematic Design Considerations 34 9.0 PCB Layout Design Considerations 40 10.0 Software Design Considerations 42 11.0 Version 2 Changes 50 12.0 Summary and Conclusions 51 13.0 References 53 Appendix A: Individual Contributions A-1 Appendix B: Packaging B-1 Appendix C: Schematic C-1 Appendix D: PCB Layout Top and Bottom Copper D-1 Appendix E: Parts List Spreadsheet E-1 Appendix F: Software Listing F-1 Appendix G: User Manual G-1 Appendix H: FMECA Worksheet H-1


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Abstract

Our project, GROVER (Ground-Roaming Offensive Vehicular Engagement Robot), is an

autonomous vehicle that is designed to look for moving heat-emitting targets and engage them

while patrolling a limited area and avoiding ground obstacles. Ultrasonic and passive IR sensors

are integrated with an off-shelf vehicle and AirSoft weaponry. The vehicle is controlled by a

Freescale (Motorola) 9S12C32 microcontroller and will “patrol” an area looking for human

targets to engage. Power is provided internally using batteries. Ultrasonic sensors are used for

obstacle avoidance and range-finding while passive IR sensors aid in the detection of human

targets. Once a human is detected, a high-torque servo is used to align the weapon with the

target.


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1.0 Project Overview and Block Diagram

GROVER is an autonomous vehicle designed to look for moving heat-emitting targets and

engage them while patrolling a limited area and avoiding ground obstacles. The block diagram

in Figure 1-1 shows that the Freescale MCU communicates with 9 separate external devices to

carry out GROVER’s duties. Two 7.2V rechargeable batteries are used in series, along with four

9V alkaline batteries to power the robot’s entire system.

Figure 1-1: GROVER Block Diagram


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Figure 1-2: Image of Final Project


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2.0 Team Success Criteria and Fulfillment

• An ability to detect a heat-emitting target – successfully demonstrated

• An ability to determine and display the number of engagements – successfully demonstrated

• An ability to fire the weapon – successfully demonstrated

• An ability to turn weapon to face target – successfully demonstrated

• An ability to avoid collisions with inanimate objects – successfully demonstrated


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3.0 Constraint Analysis and Component Selection

3.1 Constraint Analysis

3.1.1 Computation Requirements

The computational requirements of GROVER include the computation of a “time of

flight” for the ultrasonic sensor for measuring distance. This is done by activating an ultrasonic

ping and waiting for an echo to be received. Upon echo reception, the ultrasonic sensor informs

the microcontroller via a logic level indicator. By utilizing the microcontroller’s timer capture

feature, one can determine the distance of an object given that the frequency of the ping is

known.

The only other computation requirements of GROVER include the timing of software

delay loops. Several delays are used to create a meaningful sequence of events in the polling

software.

3.1.2 Interface Requirements

The bulk of this robot design will be located outside of the microcontroller with a large

number of interfaces. These interfaces include four PIR (Passive Infrared) sensors, one

ultrasonic sensor, an LCD with a shift register chip utilizing an SPI channel, a miniature

paintball gun, a servo, and two tank motors. Other than the SPI channel used for the LCD

interface, general purpose I/O channels will be used as control signals for each of the other

peripheral devices.

3.1.3 Power Supply

All components will receive power from batteries in order to keep GROVER mobile. A

combination of two 7.2 volt rechargeable RC batteries and four 9 volt alkaline batteries will be

used to provide the requisite voltage levels to each component. The electronic gun motor

requires 5 volts DC drawing about 1 amp of current. The two tank motors each require 3 volts

DC also drawing at least 1 amp per motor. The RF switch requires 12 volts DC, and the PIR

sensors each require 9 volts DC with small amounts of current draw. The servo, microcontroller,

and other PCB components require a 5 volt source. The motors will not all be operating at the

same time since the robot will stop traveling before engaging any targets. This will help reduce

the overall current requirements. The two 7.2 volt rechargeable batteries will be used in series to


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create a 14.4 volt source. This will be fed straight into the RF switch which has its own voltage

regulator. Two other switching voltage regulators will be used to step down the voltage to 5

volts. One regulator will be used for the lower current drawing components like the

microcontroller and the other PCB components. The other regulator will be used for the servo,

gun, and tank motors. The four 9 volt batteries will be used for the PIR sensors. Due to their

current draw, they each require their own 9 volt battery to operate correctly.

3.1.4 Packaging Constraints

The robot tank base is approximately 4.5” by 8” so our design is limited to a fairly small

area. The main packaging constraints include mounting the four PIR sensors to the sides of the

tank, the paintball gun to the servo, and finally distributing the weight of the batteries throughout

the tank. The PCB must also be designed very compactly to fit in the small spaces of the tank.

The size and efficiency of our design will be a major design constraint. The selected

components must be small enough and light enough for the tank motors to work properly without

losing balance.

3.1.5 Cost Constraints

A maximum estimate of $500 was set to be the spending limit of our design. None of the

components chosen were very expensive on their own, so this limit did not affect too many

design choices. The tank base turned out to be the most expensive component, but having a

strong working project platform is very important. Each component has been carefully selected

to keep costs low without sacrificing functionality.

3.2 Component Selection

3.2.1 Microcontroller

The interfacing capabilities of a candidate microcontroller far outweigh its computational

prowess for our project. Our microcontroller must be capable of controlling three motors (two

drive, one turret) using pulse width modulation. Furthermore, the chosen microcontroller must

also feature timers to record a “time of flight” for our ultrasonic sensors so that an object’s range

from the GROVER can be calculated. A means of communicating with our LCD is also

required. I/O pins for interfacing with our PIR sensors, Air Soft weaponry, and other small


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components must also be taken into consideration. Based upon these requirements, we chose the

Atmel ATmega32 and the Freescale MC9S12C32 for consideration.

The MC9S12C32 sports 32KB of Flash as does the Atmel offering [3] [1]. Both

microcontrollers are also capable of fulfilling the interfacing requirements of our project.

However, the Freescale chip allows for room to grow.

Max

I/O

Pins

Freq.

Max

(MHz)

PWM

(Channels)

Timers

(Channels)

ADC

(Channels)

SPI

MC9S12C32 33 25 6 8 (16-bit) 8 (10-bit) 1

ATmega32 32 16 4 2 (8-bit)

1 (16-bit)

8 (10-bit) 1

Table 3-1: Microcontroller Comparison

Both Freescale and Atmel offer development tools that allow for the use of C code in the

project [3] [1]. However, the Atmel IC is offered as a 40-pin DIP package for a reasonable

$8.28. A 32-pin DIP package of the MC9S12C32 is made available in the form of the

M68MOD912C32 [2]. For $24.95, the Freescale module comes with the requisite capacitors,

resistors, BDM header, and an RS232 IC. This package has the advantage of serving as a

development platform as well plugging into our PCB for use in the “end product.” The

ATmega32 DIP package is just the chip itself. Additional time and money would be needed to

bring the chip to the point where it could be used as a development platform.

Experience developing commercial software using the Metrowerks CodeWarrior IDE as

well as industry contacts should help mitigate the time and cost of development. Combined with

our group’s general familiarity with the HCS12’s instruction set and capabilities, the Freescale

microcontroller came out ahead of the Atmel.

3.2.2 Ultrasonic sensors

Two ultrasonic sensors were considered, the Devantech SRF04 and Devantech SRF08.

The SRF08 has twice the sensing range of SRF04, but requires an I2C bus connection [6] [7].

Further comparison can be found in Table 3-2 below.


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Devantech SRF04 Devantech SRF08

Cost $33.50 $56.00

Interface to the

microcontroller

A single input line for the

trigger pulse and a single

output line for the echo

pulse

I2C bus

Average current

consumption

50 mA max, typically 30

mA

275 mA max, typically 40

mA

Range Max: 3 m, Min: 3 cm Max: 6m, Min: ~ 1 cm

Table 3-2: Ultrasonic Comparison

The component selected was the SRF04 because it is cheaper, has a reasonable range to be used

in the design, and the interface is much simpler because it doesn’t require an I2C bus interface.

3.2.3 PIR sensors

The criteria used to select the PIR sensors were mainly the availability and ease of

interfacing with the microcontroller. Three alternatives were considered, the Heath/Zenith SL-

6030-WH5, Heath/Zenith SL-5408-WH, and Kitsrus K30 [10] [9] [8]. The Heath/Zenith PIR

sensors can be easily purchased from a local Wal-Mart or hardware store, while the Kitsrus K30

has to be ordered through an online retailer.


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Heath/Zenith SL-

5408-WH

Heath/Zenith

SL-6030-WH5

Kitsrus K30

Cost $9.99 $19.99 $20.95

Output form 110 VAC Half sine-wave

with about 3V

peak value

9V DC pulse

Power supply 110 VAC 3 VDC 9 VDC

Modifications needed

to interface with the

microcontroller

Need to remove the

relay, convert the

output to DC and

add DC power

supply

Need to make the

output in the form

of pulses

Reduce output

voltage from 9V to

about 5 V

Assembly needed minimal none full

Table 3-3: PIR Comparison

The PIR sensor that was chosen was the Kitsrus K-30 because of its ready to use output

for interfacing. The two other alternatives needed some extensive modifications to make them

ready for interfacing. The modifications needed for the Heath/Zenith SL-5408-WH PIR sensor

were considered too much and overshadowed the cost and easiness of purchase [9]. For the

Heath/Zenith SL-6030-WH5, the price was slightly cheaper, but the amount of effort needed to

modify the circuit to make it ready for interfacing was also considered too much [10]. The need

to assemble the Kitsrus PIR sensor was considered a very small nuisance because the assembly

process was well documented and the instructions included with the kit were very easy to follow

[8].

3.2.4 Robot base

There are many reasons we chose the Rogue ATR Robot Base over others [13]. The first

factor was the overall look and flexibility of the base. Our group chose the ATR Base over the

BLUE Base because of the solid rectangular base, tread system, dual gear motor, and dual H-

bridge [13]. Since our robot needs to be able to climb over obstacles to a certain degree, we

decided a treaded system would be better than a two 3” wheels [13]. The rectangular base also

gives our group more flexibility when fitting the paintball gun turret and servo because of the


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multiple levels and strong controller mounting standoffs. Although the Rogue ATR Robot Base

was a little more expensive than the Rogue Blue Robot Base, we believe the ATR is an excellent

choice for our project and we are very confident that it will meet all of our requirements.

3.2.5 LCD

The Hitachi LM044L and the OPTREX DMC20261A were the two alternatives

considered for the LCD. Both allow the use of the Hitachi HD44780A00 driver [11] [12].

Hitachi LM044L OPTREX DMC20261A

Cost $10.00 Free

# of characters displayed 20 chars x 4 lines 20 chars x 2 lines

Driver Hitachi HD44780A Hitachi HD44780A

Backlit no yes

Table 3-4: LCD Comparison

Both alternatives were quite similar, but we chose the OPTREX DMC20261A because it was

obtainable for free since a group member happened to have one handy. The OPTREX LCD also

has backlighting which presents a nicer look. While the Hitachi LCD can display more

characters, it was concluded that the 2 lines x 20 chars was sufficient.

3.2.6 Paintball gun

The main idea of this project is basically to use some sort of weapon to fire on heated

targets. Due to the size of the selected robot base, a smaller weapon must be used so that the

design is not too top heavy. Our initial idea involved the use of a semi-automatic CO2 powered

Spyder paintball gun. This weapon was readily available for our free usage, but the size and

weight of this weapon was a little too much for our project. The stepper motor required to rotate

the gun would have to be very large and powerful, and the robot base would have to be much

larger to compensate for the gun weight and firing power. Another setback of that choice was

that it was semi-automatic and not fully automatic. This meant that we would have to develop

some sort of mechanical device to rapidly pull the trigger of this gun. The size, weight, and

firing method factors pushed us in another direction.


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The next idea was to use an Airsoft electronic weapon. This weapon was a fully

automatic, battery powered machine gun that was capable of shooting 6 millimeter paintballs or

pellets very rapidly. Being electronic, the gun is much easier to fire on command successfully

without mechanical failure. The electronic interface also became more realistic and more useful

for our microcontroller. The gun also weighs less than one pound, does not require CO2, and is

only 12” in length. It is fairly cheap and can easily be cut down in size since it is made of

plastic. This Mini Electric Airsoft machine gun easily became the logical choice.


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4.0 Patent Liability Analysis

4.1 Results of Patent Search

Although there is no United States patents found that completely encompassed the

GROVER project, there were several patents for components of the GROVER project that may

be infringed upon. With the use of United States Patent and Trademark Office website [35] and

a previous ECE 477 project [36], the patents in Table 1.0 were found that may cause possible

infringement.

U.S. Patent

Number

Abstract

6,414,457

Filing Date:

16 Aug 00

An autonomous rolling robot is in the form of a hollow sphere containing at

least two sets of rotors. Each set of rotors includes a rotor mounted on a shaft

which is driven by a motor. All of the shafts are radially mounted within the

hollow sphere so that an extension of the shafts would intersect at the

geometric center of the sphere. The center of mass of the robot is also located

at the geometric center of the sphere. [30]

6,532,404

Filing Date:

1 Mar 02

System of guidance and positioning relative to a fixed station for an

autonomous mobile robot utilizing at least a directional infra-red beam emitted

by the fixed station, the mobile robot being provided with a directional system

of detection of infra-red emission connected to a microcomputer incorporated

in the said robot, the robot moving on a work surface in an essentially random

manner, the microcomputer including an algorithm able to control the return to

fixed station by displacement of the robot towards the direction of emission of

said infra-red beam, characterized in that the infra-red beam is a narrow

directional beam and in that the system of detection is located on a frame at the

center of rotation of the robot, oriented in the direction of movement of the

robot, precise positioning in the fixed station being carried out by rotation of

the machine around a vertical axis according to an algorithm based on the

detection of the narrow beam. [31]

6,339,735

Filing Date:

There is disclosed a utility robot for operating in multiple modes, in particular,

at least one autonomous mode and at least one manual mode. The robot is


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29 Dec 98 configured with a recognition system for recognizing a signal indicating the

particular mode in which to operate, and adjusts its control system accordingly.

Methods for operation of this utility, performing various tasks, such as lawn

mowing, vacuuming, floor cleaning and snow removing are also disclosed.

[32]

6,515,614

Filing Date:

11 Oct 01

An autonomous moving apparatus moving to a destination while detecting and

avoiding an obstacle includes a radar device for scanning a horizontal plane in

its traveling direction to thereby detect a position of an obstacle and an

obstacle sensor for detecting an obstacle in a space different from the scanning

plane of the radar device. The apparatus moves to the destination under such

control as to avoid the obstacle based on detection information from the radar

device and the obstacle sensor from a detection output provided by a specific-

configuration detecting element for detecting a present specific configuration

from scanning information by the radar device. By providing such a specific-

configuration detecting element that detects a specific configuration based on

the scan information by the radar device that can accurately know about

position information, it is possible to guess an obstacle having an upper

structure, thus providing efficient avoidance. [33]

6,539,284

Filing Date:

25 Jul 01

A robot for performing substantially autonomous movement includes a

processing device, a memory, and a mobility structure controlled by the

processing device. The processor directs the robot to move with any

predetermined safe area having a boundary and a reference point. Optionally,

the robot also exhibits features of social interactivity by accepting an input

from a human, selecting dynamic content from a data base wherein the

dynamic content is responsive to the input, and presenting the human with a

response corresponding to the dynamic content selection. [34]

Table 4-1: United States Patents researched for project GROVER [35]


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4.2 Analysis of Patent Liability

4.2.1 U.S. Patent 6,414,457 [30]

This patent relates to an autonomous rolling robot with rotors mounted on a shaft which

is driven by a motor. The GROVER project is also an autonomous robot with rotors driven by

two motors. The two robots differ in that the patent describes the robot as a “hollow sphere

containing at least two sets of rotors” and the GROVER project has multiple rotors driven by two

motors connected by a tank base. Though the two differ in shape and construction, this could be

an infringement under the doctrine of equivalents, but since there is so much prior art that is

similar it is highly unlikely.

4.2.2 U.S. Patent 6,532,404 [31]

This patent relates to the guidance and positioning of an autonomous robot. The

GROVER project uses both ultrasonic and passive infrared (PIR) sensors with a microprocessor

for the guidance and positioning. From the above patent, an infrared beam and microcomputer

are used in the guidance and positioning of the autonomous robot. Though it is difficult to

extract the exact meaning of what the patent is trying to convey, it seems that both autonomous

robots are using the same method for guidance and positioning, but again since there is prior art

this is probably not an issue.

4.2.3 U.S. Patent 6,339,735 [32]

This patent relates to the use of multiple modes, automatic and manual. Through the use

of an RF transmitter, the GROVER project has the ability to turn the autonomous robot on and

off for safety purposes. Because the GROVER is used as a weapon, there needs to be a mode

where the user can refill ammunition or just move the GROVER when necessary. Though the

patent describes multiples modes, this can be contested because the GROVER does not

necessarily have a “manual” mode, just an automatic and an off. With that said, this may be seen

as an infringement under the doctrine of equivalents because of the multiple modes, but two

modes would probably not make it an issue.


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4.2.4 U.S. Patent 6,515,614 [33]

This patent is similar to GROVER in the aspect of “autonomous moving apparatus

moving to a destination while detecting and avoiding an obstacle.” The GROVER uses

ultrasonic sensors to avoid obstacles and compute distances as it roams around a designated area.

The device described in the patent uses a “radar device” to avoid obstacles, but the patent does

not discuss the details of how this works. This could possibly be seen as an infringement under

the doctrine of equivalents because both devices are detecting and avoiding an obstacle through

some method of sensors, but due to the lack of detail on the patent it can be argued that

ultrasonic is not radar therefore not infringing upon this patent.

4.2.5 U.S. Patent 6,539,284 [34]

This patent relates to the use of a “robot for performing substantially autonomous

movement includes a processing device, a memory, and a mobility structure controlled by the

processing device” and “social interactivity.” The GROVER is an autonomous robot that uses

sensors and a microprocessor to detect and fire upon heat-emitting sources, including humans.

This could possibly be seen as infringement under the doctrine of equivalents because the

GROVER is using practically the same components with social interactivity. However, the

patent does describe the social interactivity as “input from a human,” and in the case of

GROVER, the input would be the human’s body heat. Although not entirely clear, there are

substantial similarities between the two devices for infringement.

4.3 Action Recommended to Avoid Infringement

In the case where there are possible infringement liabilities, a few things could be done.

First of all, before obtaining any licenses or paying any royalties, the GROVER project team

would look to the assistance of a patent lawyer. If the patent lawyer found that the infringement

liabilities were real, as stated above, the team would need to purchase any licenses or pay

royalties for any component that is used on the GROVER. For instance, a license would

probably need to be purchased for the use of PIRs and a microprocessor for the guidance and

positioning of the autonomous robot [33]. The other alternative, if the team is not able to

purchase a license or the owner is not willing to sell, would be to design GROVER in a way that

accomplishes the same task but with out infringing on the particular patent. For instance, instead


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of having multiple modes, GROVER could possibly be in automatic mode without an alternate

mode. Although this is not efficient, it is possible and it eliminates the need for that particular

patent [32].


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5.0 Reliability and Safety Analysis

5.1 Reliability Analysis

The following components were determined to be most likely to fail based on the

operating temperature and the amount of current produced/consumed:

1. Freescale 9S12C32 microcontroller [28]

2. Linear Tech LT 1374-5 switching regulator [41]

3. Linear Tech LT 1376-5 switching regulator [40]

4. 4N28 phototransistor output optocoupler [42]

5.1.1 Freescale 9S12C32 Microcontroller Reliability Analysis

5.1.1.1 Assumptions

Variable Value Assumption / Explanation

C1 0.28 16-bit CMOS microprocessor [28] [39]

EA 0.35 eV VHSIC CMOS [39]

TJ 125º C Maximum operating temperature for the microprocessor [28] [39]

πT 3.1 Values corresponding to device’s EA & TJ [39]

C2 0.13 Based on 28 functional pins and nonhermetic surface mount package

[39]

πE 4.0 Ground Mobile installation [39]

πQ 1.0 Assumed as class B [39]

πL 1.0 Assume first production date the same as original datasheet release date

(01/25/2003) so years in production > 2 years [28] [39]

Table 5-1: Assumed values for reliability analysis of Freescale 9S12C32 microcontroller

5.1.1.2 Calculations

The predicted number of failures every 106 hours is calculated using the following formula:

λλλλp = (C1 πT + C2 πE) πQ πL Failures / 106 hours

For Freescale 9S12C32, using the values assumed above, the number of failures every 106 hours

is:

λλλλp = 1.388 Failures / 106 hours

Therefore the mean time to failure (MTTF) is


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MTTF = 1 / λλλλp

= 1 / (1.388 x 10-6)

= 7.205 x 105 hours

5.1.2 Linear Tech LT 1374-5 Switching Regulator Reliability Analysis

5.1.2.1 Assumptions


C1 0.040 Linear CMOS with 301-1000 transistors [39]

EA 0.65 eV Linear MOS [39]

TJ 125º C Maximum operating temperature for the regulator [41] [39]

πT 58 Values corresponding to device’s EA & TJ [39]

C2 0.0025 Based on 6 functional pins and nonhermetic surface mount package

[39]



πL 1.0 Assume first production date the same as datasheet copyright date

(1998) so years in production > 2 years [41] [39]

Table 5-2: Assumed values for reliability analysis of Linear Tech LT 1374-5 switching

regulator




For Linear Tech LT 1374-5, using the values assumed above, the number of failures every 106

hours is:




= 1 / (2.33 x 10-6)

= 4.292 x 105 hours


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5.1.3 Linear Tech LT 1376-5 Switching Regulator Reliability Analysis

5.1.3.1 Assumptions


C1 0.040 Linear CMOS with 301-1000 transistors [39]

EA 0.65 eV Linear MOS [39]

TJ 125º C Maximum operating temperature for the regulator [40] [39]

πT 58 Values corresponding to device’s EA & TJ [39]

C2 0.0025 Based on 6 functional pins and nonhermetic DIP package [39]



πL 1.0 Assume first production date the same as datasheet copyright date

(1995) so years in production > 2 years [40] [39]

Table 5-3: Assumed values for reliability analysis of Linear Tech LT 1376-5 switching

regulator




For Linear Tech LT 1376-5, using the values assumed above, the number of failures every 106

hours is:




= 1 / (2.33 x 10-6)

= 4.292 x 105 hours


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5.1.4 4N28 Phototransistor Output Optocoupler Reliability Analysis

5.1.4.1 Assumptions


λλλλb 0.013 Phototransistor output, single device [39]

TJ 100º C Maximum operating temperature [42] [39]

πT 6.6 Value corresponding to device’s TJ [39]


πQ 8.0 Plastic [39]

Table 5-4: Assumed values for reliability analysis of 4N28 phototransistor output

optocoupler



λλλλp = λλλλb x πT x πx x πQ Failures / 106 hours

For 4N28, using the values assumed above, the number of failures every 106 hours is:




= 1 / (5.4912x 10-6)

= 1.8211 x 105 hours

5.1.5 Conclusion of System Reliability

The limiting factor of the reliability analysis is the 4N28 output optocoupler. Its MTTF

value of 1.8211 x 105 hours is the shortest of the four analyzed components. The optocoupler,

however, is not the limiting factor of the system’s reliability. The system’s reliability is limited

by the mechanical parts that are used in the system. Mechanical parts, such as the rubber treads,

motors, and AirSoft gun, have been determined to have a lifespan of 1 to 2 years. Consequently,

mechanical parts will fail sooner than the electronic components. Higher durability mechanical

components should be substituted when GROVER is manufactured to mitigate this factor. Easy

access to spare parts should be provided to the customer as well as a 3 year warranty to cover

initial breakdown of mechanical parts.


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5.2. Failure mode, Effects and Criticality Analysis (FMECA)

5.2.1 Major Functional Blocks

For the failure mode, effects, and criticality analysis (FMECA), the design has been

divided into 7 major functional blocks; chip power supply, motors power supply, microcontroller

and interface headers, PIR interfaces, LCD interface, H-Bridge and servo motor interfaces and

gun interface.

5.2.1.1 Chip Power Supply (Block A)

The chip power supply block contains a switching regulator, a few capacitors and diodes

and an inductor. The power supply can supply up to 1.25 A of current.

Figure 5-1: Schematic of functional block A (chip power supply)

5.2.1.2 Motors Power Supply (Block B)

The motors power supply block contains a switching regulator, a few capacitors and

diodes and an inductor. The power supply can supply up to 4.25 A of current.

Figure 5-2: Schematic of functional block B (motors power supply)


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5.2.1.3 Microcontroller and interface headers (Block C)

This block contains the Freescale 9S12C32 microcontroller unit (MCU) that is embedded

in a 32-pin DIP module. This block also contains interface headers to the MCU module.

Figure 5-3: Schematic of functional block C (MCU)

5.2.1.4 PIR interfaces (Block D)

This is the PIR sensors interface to the chip. The input voltage from the PIR sensors is

divided using a voltage divider.

Figure 5-4: Schematic of functional block D (PIR interfaces)

5.2.1.5 LCD interface (Block E)

This block contains a shift register to shift data to be displayed on the LCD. This block

also contains the necessary circuitry to supply power, data and command to the LCD module.


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Figure 5-5: Schematic of functional block E (LCD interface)

5.2.1.6 H-Bridge and Servo motor interfaces (Block F)

This block contains interfaces to the H-bridge and servo motor

Figure 5-6: Schematic of functional block F (H-bridge and servo interfaces)

5.2.1.7 Gun interface (Block G)

This block contains a 4N28 opto-isolator, a TIP 122 Darlington transistor, a diode, and a

couple resistors.


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Figure 5-7: Schematic of functional block G (gun interface)

5.2.2 FMECA Worksheet

For the FMECA worksheet, two criticality levels, high level and low level, for types of

failures in the output of the design have been determined. A failure rate λ smaller than 10-9 has

been deemed necessary for failures with “high” level of criticality. This criticality level is given

to a failure that can possibly cause injury to the user, unpredictable robot actions, permanent

damage to the microcontroller and other discrete components and/or lost of user control over the

robot’s actions. Failure rate λ between 10-9 and 10-4 has been assigned for “low” level of

criticality. This criticality level is given to a failure that can cause the robot not functioning

properly but does not cause bodily injury to the user and/or the robot just not functioning at all.

The FMECA worksheet can be found in Appendix H.


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6.0 Ethical and Environmental Impact Analysis

6.1 Ethical Impact Analysis

During GROVER’s design process, system safety and predictability were deemed

primary concerns. Due to GROVER’s stated objective of interacting with humans in an

aggressive fashion, improper use could result in serious injury. Secondary to safety, the

product’s lifespan was also given a great deal of thought. GROVER was designed to have a

minimal failure rate and maximum durability. Much of the design process for both durability

and safety is synergistic in nature. A durable product is less prone to failure and a product less

likely to fail is safer. Thoughtful design not only spares the company of possible legal expenses,

it also pays dividends in customer satisfaction and brand loyalty.

6.1.1 Safety Concerns

As an ethically-conscious design team, our primary concern is the safety of our

customers. Countless hours have been spent to ensure that the system will not cause injury to the

user in normal operation or in the event that a failure occurs.

One concern is the possibility that the system could go to an unpredictable state due to a

software bug, a damaged sensor or other component, or a combination of failures. This concern

was addressed by adding an RF “kill-switch.” If the system were to go into an erroneous state,

power to GROVER can be cut off from a distance by depressing a button on the key-fob. While

this addition adds to the cost of production, ensuring customer safety is considered more

valuable.

Another safety concern is that the munitions fired from GROVER’s weaponry may cause

injury to the user. By affixing warning labels on the robot and in the user manual, users are

informed of the potential danger and advised of actions they should take to minimize their risk.

Warning labels will state that those using GROVER should always wear protective eyewear and

a regulation paintball chest protector. This will not be hard to enforce since GROVER’s

intended use is in paintball arenas. Paintball arenas require that participants wear protective

gear or sign a waiver prior to entering the arena.

The possibility of electric shock from exposed electrical components or stripped wires

was also contemplated during GROVER’s design. By using covered connection headers to

connect the interfaced components to main PCB and using electrical tape, heat shrink, or wire


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caps to cover exposed connections, this concern was mitigated. As an extra safety precaution,

warning labels will be affixed to the robot and in the user manual. The warning labels shall warn

the user of the danger of electric shock if the packaging of GROVER is opened or if wires

become exposed.

6.1.2 Product Lifespan

An ethical organization should not sell products that have an unreasonably short lifespan

or a particularly high occurrence of failure. In keeping with this philosophy, the design team has

done extensive testing and analysis of possible failure modes. A Safety and Reliability Analysis

report, including an FMECA (Failure Mode, Effect, and Criticality analysis) worksheet, was

completed by team members. From the report, most critical failures can be identified. Since the

product is currently in its development stage, the MTTF (Mean Time-To-Failure) values of the

critical components are not as high as one would like them to be. Through the analysis of current

components failures, improvements can be made to ensure the end product will have a markedly

longer lifespan.

6.2 Environmental Impact Analysis

As responsible designers, we must be cognizant of the potential hazards associated with

not only GROVER’s normal usage, but also the environmental ramifications associated with its

manufacture and disposal.

6.2.1 Product Manufacture

GROVER’s design utilizes a number of printed circuit boards (PCBs) throughout its

structure linked to a common main board. The main board, as well as the H-bridge, ultrasonic

range finder, RF switch, and the four PIR sensors, constitutes a potential environmental hazard.

During the various stages of PCB manufacturing, a number of hazardous by-products are

generated. Industrial wastewater and treatment residues, spent process baths, acids used for

cleaning equipment, copper sulfate crystals, and re-flow oil constitute the typical waste generated

by PCB manufacturers [18]. While elimination of all wastes is unrealistic, certain actions can be

taken by both board designers and manufacturers to minimize waste. If GROVER were to go

into mass production, many of the through-hole and dual-in-line package (DIP) components


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could be replaced with their surface mount technology (SMT) equivalents. SMT parts allow for

closer contact area of chip leads compared to through-hole components. By using SMT parts

when possible, the PCB needs to be only 35 to 60 percent as large as a board designed with

through-hole components [19]. Efforts by manufacturers can also help to curb waste. Material

substitution, such as abrasives and non-chelated cleaners for conventional halogenated solvents

for board preparation, and reusing/recycling the various rinses and baths employed during

manufacture, can lead to a significant reduction in generated waste [19].

6.2.2 Normal Use

During normal use, GROVER presents minimal environmental concerns. GROVER’s

principle source of power is a pair of 7.2-Volt nickel-metal-hydride batteries. Nickel-metal-

hydride is considered to be environmentally friendly [20]. Although the main derivative is

nickel, which is considered semi-toxic, each battery contains also contains electrolyte, which is

hazardous in large amounts. The sum total of electrolyte present in two batteries is of little

concern. GROVER’s PIR sensors, however, utilize a 9-Volt alkaline battery. Alkaline batteries

contain a strong alkali, potassium hydroxide electrolyte [21]. If the alkaline battery were to be

damaged or mishandled, it is possible for the potassium hydroxide to leak out of the battery. In

the event that the electrolyte comes into contact with the skin or eyes, severe chemical burns can

result [21]. By providing proper handling instruction for the batteries in the instruction manual,

as well as encouraging battery recycling, GROVER’s potential environmental hazard is

negligible.

6.2.3 Disposal

GROVER’s greatest impact on the environment occurs after its operational life has drawn

to a close. Although the customer is ultimately responsible for determining how the unit is

disposed, as a company one can offer information and incentives to encourage the customer to

make an environmentally responsible decision.

Since the bulk of PCBs consist of materials that classify them as hazardous or “special”

waste, it is important that they be properly disposed. Each of GROVER’s PCBs can be

processed to recover raw materials such as silver, lead, copper, and gold [22]. If this process

were handled by the manufacturer, the reuse of materials could lower production costs.


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The two nickel-metal-hydride batteries, while considered to be environmentally friendly,

should be recycled. During the recycling process, nickel-metal-hydride batteries produce enough

nickel to pay for the recycling process [20]. As both environmentally and economically friendly,

users should be encouraged to recycle these batteries through the use of stickers on the batteries

themselves. Furthermore, a list of recycling centers should be included in the product

documentation.

Since 1993, alkaline batteries produced in the United States contain no added mercury

and are essentially mercury-free [23]. Alkaline batteries can therefore be safely disposed of with

normal household waste. However, it is important not to dispose of a large quantity of batteries

in a group. Since disposed batteries are often not completely “dead,” a large grouping of used

batteries increases the risk that “live” batteries could come into contact with one another,

creating safety risks [24]. At this time, “proven cost-effective and environmentally safe

recycling processes are not yet universally available for alkaline batteries [24].”

GROVER’s recognizable blue base is made out of aluminum. “Although aluminum is

less than one percent of the nation's municipal solid waste stream, it remains one of the most

valuable recyclable materials [25].” With a majority of GROVER’s components recyclable, it

makes sense for the manufacturer to accept the entire GROVER assembly as recyclable material.

Those customers who recycle their GROVER should be rewarded with a coupon good towards

future purchases. In addition to being an environmentally friendly policy, it would also serve as

a marketing tool to elicit repeat customers.


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7.0 Packaging Design Considerations

7.1. Commercial Product Comparison

7.1.1 Foster-Miller Talon Robot

The Foster-Miller Talon Robot is the military version of our robot GROVER. The Talon

robot is 22.5 inches wide, 34 inches long, and between 11 to 62 inches tall depending on whether

the robotic arm is stretched or not [17]. The Talon can be fitted with a variety of devices and

weapons depending on the mission. The most common interfaces are the robotic arm, the night

vision camera, and an M16 riffle [17]. The Talon is tread driven with the peripherals mounted

on top of the robot similar to those of GROVER. The robot is controlled by an RF based

operator control unit (OCU) and powered using a lead acid battery located inside the chassis of

the treaded base [17].

Figure 7-1: Foster-Miller Talon Robot and the Operator Control Unit


-30-

As shown in Figure 7-1, the Talon is controlled based on the vision recorded by the

camera mounted on a robotic arm on top of the robot base. This will create a liability for the

system because the robotic arm is not as sturdy as other parts of the robot so it can easily be bent

or broken. The robotic arm, which sticks up from the robot base, will limit the robot’s

movement inside small channels or openings.

The usage of an RF based OCU both has positive and negative sides. On the positive

side, the OCU will give more control over the robot’s actions. This is very important because

the robot might be equipped with destructive weaponry and for safety purposes it is common

sense to not leave the decision of firing the weapon to a computer. The negative side is that the

RF signal could be blocked making it impossible to control the robot allowing it to be lost or

destroyed. For GROVER, we take care of the imperfections of the Talon by using sensors

mounted on the robot base’s sides for object avoidance while not using an RF based radio control

or camera. Based on the sensors’ inputs to our system, the microcontroller on board will make a

decision on which direction it needs to go. Because our robot is only equipped with a paintball

gun, gun fire control is not as crucial as the Talon’s, so decision to fire based on sensor inputs is

enough. As a safety feature, we have added an RF transmission based on/off switch for easy

power shutdown.

Another good aspect of the packaging is the usage of treads to drive the Talon robot.

This will allow the robot to explore harsh terrains with little or minimal difficulty. This is why

we are using a tread driven robot base. A treaded robot base also allows for easier turning and

drive control. Like the Talon, we also put our circuitry and power supplies inside the robot

base’s chassis for protection.


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7.1.2 Roomba Robotic Floor Vacuum

The Roomba is a commercial example of our project minus the weapon attachment and

vacuum capabilities. A 16-bit processor from Freescale Semiconductor powers the new

generation of Roomba floor vacuums and the advanced power system NiMh battery pack lasts a

full two hours [15]. The physical dimensions of the Roomba are 4 ¼” H x 13 ½” Diam and

weighs 7 ½ lbs [14]. This is approximately the same weight as GROVER.

Figure 7-2: Roomba Discovery SE Robotic Floor Vacuum

Roomba uses four sensors to navigate. These sensors include the Wall Following Sensor,

a Cliff Avoidance Sensor, a Virtual Wall Sensor and the bumper of the Roomba is a contact

sensor. The three non-contact sensors send invisible light in front of them and the robot

navigates by sensing the light’s reflections [16]. A positive aspect of the Roomba is that it is

compact and weighs very little. This is one aspect we are hoping to achieve with the GROVER.

Another aspect of the Roomba which will go in our design is the use of a remote control to

power the robot on/off. The Roomba however is dependent upon the remote control whereas our

design is only used in emergency instances.


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7.2 Grover Illustrations

o See Appendix B.

7.3 Materials List

Material Quantity Purpose

Plastic Wall Socket Mounts 2 Turret Shell

Medium Sized L Brackets 3 Support servo for turret

Small Sized L Brackets 12 Mounting LCD/Batteries

Aluminum Standoffs 30 Mounting PIR Sensors/Ultrasonics

Expanding Tank Area

Mounting Hardware (Nuts,

Bolts)

50 Mounting Sensors/Components

Holding tank together

Table 7-3: Materials List

7.4 Tooling Requirements

Since the tank base has been already constructed from a kit, the main factor for building

GROVER is the construction of the turret. We will be using a dremel saw bit to cut down the

Airsoft gun size. We will reduce its length from 12.5 inches to about 9 inches. We will also

remove the handle and trigger so that it fits nicely in the turret case. We will use the dremel to

also cut the plastic casing for the turret to hold the gun. Holes will need to be drilled through the

metal tank plates to mount each sensor. Other than that, no special tools will be required for the

construction of GROVER.


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7.5 Component List With Estimate of Packaging Weight and Cost

Table 7-4: Estimate of Packaging Weight and Cost

Part Unit Cost Quantity Final Cost Total Weight

(Max Estimate)

Micro-Controller $24.95 1 $24.95 1 oz

PIR Motion

Detector

$20.95 4 $83.80 4 oz

H-Bridge $ 0.00 1 $ 0.00 2 oz

Ultrasonic Range

Finder

$33.50 1 $33.50 2 oz

Robot Base $139.95 1 $139.95 24 oz

Robot Extra Level

Kit

$29.95 1 $29.95 3 oz

LCD $0.00 1 $0.00 2 oz

Airsoft/Paintball

Gun

$18.50 1 $18.50 14 oz

RF switch $45.95 1 $45.95 2 oz

Servo $23.00 1 $23.00 4 oz

Gun Mount $20.00 1 $20.00 6 oz

PCB $0.00 1 $0.00 3 oz

Alkaline Batteries $4.00 4 $16.00 8 oz

7.2v 2100mAh

NiCD Battery Pack

$31.99 2 $63.98 25 oz

Miscellaneous

Mounts, Wires,

Small Components

$15.00 1 $15.00 4 oz

Total: $514.58 104 oz (6.5 lbs)


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8.0 Schematic Design Considerations

8.1 Theory of Operation

8.1.1 M68MOD912C32

The M68MOD912C32 module contains a Freescale 9S12C32 microcontroller, an RS232

transceiver circuit, an 8-MHz crystal oscillator, a PLL circuit, a local 5V low-dropout 100 mA

regulator, a standard 6-pin BDM connector, and an on-chip serial monitor [2]. The Freescale

microcontroller will be the “brain” of the robot and based on sensor input, it should be able to

assert the proper control signals to the peripherals to achieve its goal.

The microcontroller will be integrated with four PIR (passive IR) sensors to detect

moving heat emitting objects. Upon target detection, the microcontroller will receive a 5V pulse.

Four general purpose I/O (Input/Output) pins, AN0 to AN3, will be used to receive the outputs

from the sensors.

An LCD will be interfaced to the microcontroller utilizing the microcontroller’s SPI

capability. For this, four pins of the microcontroller will be used. Pin PM5 will be used to supply

SCK to the shift register. Three general purpose I/O pins, PM2 to PM4, will be used to supply

the SDO, Enable, R/W (read/write), and RS (Register Select) bits to the LCD module.

An additional four general purpose I/O pins, PT0 to PT3, will be used as output pins to

the H-bridge to drive the direction of the robot. The output pins shall output 5V or 0V pulses

depending on the direction the robot is driven to. Pin PT4 will be used to output pulses, regulated

by the built-in PWM, to the servo to rotate the gun turret, while pin PM0 will be used as a

general purpose I/O pin to supply 5V to the gun’s switch to start firing the weapon.

The robot will also be equipped with an ultrasonic sensor for obstacle avoidance. The

ultrasonic will be interfaced through pins PT6 and PT7. Pin PT7 will output trigger pulse to the

sensor, while pin PT6 will receive the input from the ultrasonic sensor. The microcontoller’s

built-in timer-capture function will calculate how long it takes for an echo to be received. Using

the speed of sound and the “time of flight” of the pulse, one can calculate the distance of the

object.

The microcontroller will be supplied with 8 MHz oscillator which means the internal

clock speed will be 4 MHz [2]. This clock speed is chosen because the module was built with

that speed and the speed was deemed adequate for our application. The power source of the


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microcontroller will come from the switching power regulator at 5V. This is an optimal voltage

because most of our peripherals will also be supplied using that level.

8.1.2 Power supply components

8.1.2.1 Generic 7.2V NiCad rechargeable batteries

Two generic RC batteries will be connected in series as the main power supply. Because

of the series connection, the power supply input voltage will be 14.4 V. This voltage will then be

stepped down using various switching regulators to fulfill the various voltage requirements of the

circuit.

8.1.2.2 Linear Tech LT 1376-5 Switching Regulator Step Down Converter

This regulator will be used to supply the M68MOD912C32, the ultrasonic sensor, the

LCD and the H-bridge circuit with 5V. This regulator is capable of supplying up to 1.25A and

can take an input voltage from 6 to 25 Volts. This switching regulator is preferred over a linear

regulator because of its efficiency, which can be close to 90% [40]. The voltage and current

supplied by this regulator is sufficient for the microcontroller module and its input range readily

accepts the 14.4 V supplied by the batteries. This regulator can also supply enough current to

drive the LCD and various chips on the PCB (such as the 74HC164 and the 4N28 optical

isolator). Because a switching regulator is used, external components need to be used to help

regulate the voltage, as shown in Figure 8-1.

Figure 8-1: Implementation of the step down Buck converter using the LT 1376-5


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8.1.2.3 Linear Tech LT 1374-5 Switching Regulator Step Down Converter

This regulator will be used to supply the drive motors, the gun motor, and the servo with

5V. The power supplies for the motors were separated to reduce noise and electro-magnetic

interference to sensitive chips and microcontroller. This regulator is capable of supplying up to

4.25A and can take an input voltage from 6 to 25 Volts [41]. This switching regulator is

preferred over a linear regulator because of its efficiency. The Voltage and Current supplied by

this regulator is sufficient for the motors and its input range can readily accept the 14.4 V

supplied by the batteries. Because a switching regulator is used, external components need to be

used to help regulate the voltage, as shown in Figure 8-2.

Figure 8-2: Implementation of the step down Buck converter using the LT 1374-5

8.1.2.4 Additional external batteries

An off-shelf 9V batteries will be used to power the PIR sensors. They will connected

directly to the components they are powering

.


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8.1.3 Peripherals

8.1.3.1 Devantech SRF04 Ultrasonic sensor

The ultrasonic sensor will be interfaced through pins PT6 and PT7. Pin PT7 will output

trigger pulse to the sensor that should be held high for at least 10 µs to signify that the sensor is

triggered. Pin PT6 will receive the input from the ultrasonic sensor and the built in timer will

calculate the time of the input pulse is held high [6]. Based on how long the pulse, the distance of

the object can be known. The pins will be connected to the sensor through a header. The

ultrasonic sensor’s power will be regulated by the LT 1376-5 converter.

8.1.3.2 PIR sensors

The microcontroller will be integrated with four PIR (passive IR) sensors to detect heat

emitting moving objects. Four general I/O (Input/Output) pins, AN0 to AN3, will be used to

receive the inputs from the sensors, which are connected through the header. The PIR sensor will

output 9V pulse when a heat emitting moving target is detected [8]. Because the microcontroller

can only take up to 5V pulse, a voltage divider is used. Resistors with the values 1kΩ and 1.2 kΩ

will be used as the voltage divider.

Vout = (Rbelow/(Rup+Rbelow)) * Vin

5 = (Rbelow/(Rup+Rbelow)) * 9

Rbelow/(Rup+Rbelow) = 5/9

1.2 kΩ / (1kΩ + 1.2 kΩ) ≈ 5/9

The PIR sensors will be powered using an external 9V battery. The voltage divider circuit

is shown in Figure 8-3.

Figure 8-3: PIR voltage divider circuit


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8.1.3.3 LCD

The LCD will be interfaced to the microcontroller utilizing the SPI capability of the

microcontroller. For this, four pins of the microcontroller will be used. A shift register,

74HC164, will be used to register data to be displayed on the LCD. Pin PM5 will be used to

supply SCK to the shift register. Four general I/O pins will be used to supply SDO to the shift

register, Enable signal, R/W (read/write) bit and RS (Register Select) bit to the LCD module[12].

These pins are PM2 to PM4. The LCD will be connected to the PCB by a 7x2 header. Both the

LCD and the shift register powers are regulated by the LT 1376-5 converter.

8.1.3.4 Servo

Pin PT4 will be used to output pulses regulated by the built-in PWM to the servo to rotate

the gun turret [43]. The servo’s power will be regulated by the LT 1374-5 converter.

8.1.3.5 Paintball Gun

Pin PM0 will be used as a general purpose I/O pin to switch the gun to start fire. The

gun’s motor will be optically isolated using the 4N28 optical isolator. The optical isolator’s

power will be regulated by the LT 1376-5 converter while the gun’s motor will be regulated by

the LT 1374-5 converter.

8.1.3.6 Drive Motors and H-Bridge

Four general purpose I/O pins, PT0 to PT3, will be used as output pins to the H-bridge to

drive the direction of the [44]. The drive motors will be connected and powered through the H-

bridge. The power supply to the drive motors will be regulated by the LT 1374-5 converter,

while the H-bridge’s power will be regulated by the LT 1376-5 converter.

8.2 Documentation for Circuit Design

8.2.1 OrCAD schematic

o See Appendix C-1

8.2.2 OrCAD design rule check report

o See Appendix C-2


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8.2.3. OrCAD bill of materials report

o See Appendix C-3


-40-

9.0 PCB Layout Design Considerations

9.1 PCB Layout Design Considerations:

9.1.1 Board Size

The robot tank base is approximately 4.5” by 8” so the design is limited to a fairly small

area. The dimensions of the board are 4.25” by 5.575” and drill holes have been placed on the

design using a printout and the tank base. Board size was not as much of a challenge as it is was

for some groups because the GROVER board only has about 50 components and using a 32-pin

microcontroller module made routing and placement much easier.

9.1.2 Component Placement

Because of the small number of components and relatively large board space, component

placement was quite simple. Some consideration came into play with the power supplies for the

motor and the microcontroller. A main consideration was keep the diodes and capacitors as

close to the components as possible without causing difficult and unneeded routing problems.

None of the components were placed on the bottom of the board because there was no need for

this. If the design became tight on space placing parts on the bottom of the board would be

essential.

9.1.3 Signal Routing

For our PCB, signal routing was dependent upon current needs for each component. For

the majority of the routing on the PCB a 12 mil connection was used except for power and

ground routing in which 50 mil was used. One component to notice is the voltage regulator for

the motor power in which 50 mil routing was needed for 4 of the 8 pins. However this became

tricky because the pins are so close together, so 50 mil was used up to the pin and then changed

to 40 mil which is still enough to handle the current needs. All together, 19 vias were used in the

final routing of the board.

9.1.4 Footprints

Choosing footprints was probably the most tedious part of the layout process. For each

part a measurement of the component was taken and then the appropriate footprint was found

using the OrCAD library. The group had about 80% of the parts in hand, so most of the


-41-

footprints were found. However, one or two parts were created using the OrCAD Layout library

tool. Once the footprints were found for each component, the parts there were in hand were

placed on a 1 to 1 ratio printout to double check size and pin placement was correct. With the

use of parts in hand, data sheets, and printout measurements, all footprints were found to fit

properly.


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10.0 Software Design Considerations

The lack of extensive library use combined with our team’s experience writing assembly

using Motorola’s instruction set led us to choose assembly as the language we would write our

application code in. Metrowerks’ CodeWarrior IDE (integrated development environment) [26]

belies the true complexity associated with the MC9S12C32 memory model and generates

suitable startup code for the microcontroller. In addition, CodeWarrior’s generated include file

[27] associates mnemonics with all of the memory-mapped registers and ports allowing

programmers to write code more efficiently.

10.0.1. Memory Model

The memory of the MC9S12C32 consists of 32 kilobytes of Flash EEPROM (erasable in

512-byte sectors) and 2 kilobytes of RAM. As shown in Table 10-1., 2 kilobytes of the Flash

memory is occupied by the Serial Monitor, which leaves approximately 30K for our program to

reside in. Since our program is implemented in assembly and does not have extensive library

overhead, the program size limitation should not constitute a design constraint.

10.0.2. Memory Map

Addresses $0000 through $FFFF of the MC9S12C32 map as follows [28]:

Address Range Maps to:

$0000 - $03FF 1K Register Space

$0400 - $07FF Unused

$0800 - $0FFF 2K RAM

$1000 - $3FFF Unused

$4000 - $7FFF 16K Lower Block of Flash

$8000 - $BFFF 16K Middle Block of Flash

$C000 - $FFFF 16K Upper Block of Flash

- $F780 - $F7FF User-defined Interrupt Vectors

- $F800 - $FFFF Protected (Serial Monitor)

Table 10-1: MC9S12C32 Memory Map


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While the MC9S12C32 has 32K of physical Flash memory, there is 48K of addressable space.

Both the upper and lower Flash address blocks map to physical memory, while the 16K middle

block of flash maps to either the lower or upper block. Both the register space and the RAM are

mappable to any 2K boundaries. The use of Metrowerks’ CodeWarrior IDE resolves memory

mapping issues allowing the programmer to focus attention on application code.

10.0.3. Startup Code

Startup code is automatically generated by the CodeWarrior IDE. By selecting an

MC9S12C32 stationary, CodeWarrior automatically creates the appropriate memory map,

interrupt vectors, and I/O device mapping as well as an entry point for our application code [27].

10.0.4. Organization of Embedded Application Code

The application code is organized in the form of a polling loop (shown in Figure 10-1.).

Coming out of reset, GROVER goes through its initialization routines and resets all of its

variables. A 10 second delay allows those who do not wish to be seen as a potential target to get

out of GROVER’s range. GROVER then enters its main polling loop. If any of the perimeter

PIR sensors have been triggered, GROVER halts its drive motors and begins turning its turret

towards the target (based on which perimeter sensor was triggered). As the turret is turning,

GROVER polls its narrow focus PIR sensor located on the turret. If the turret PIR sensor is

triggered, GROVER knows that the target is directly in front of the weapon. GROVER stops the

turret and fires a 5-shot burst at the target. The engagement flag is set and GROVER returns to

its main polling loop.

If, while searching for a target, the turret has reached its maximum turning potential and

the target has not been located, GROVER resets its turret to the forward position. GROVER

then engages the drive motors to rotate the entire vehicle 90 degrees in the direction of the target

and returns to the main polling loop to reevaluate the PIR perimeter sensors given its new field

of vision.

In the event that only the forward perimeter PIR sensor is triggered, GROVER uses a

modified searching sweep shown in Figure 10-2. By quickly checking only the area not covered

by the side-mounted PIR sensors, GROVER can locate and engage targets that may be slightly


-44-

askew with the front of the vehicle. Since the two side sensors can clearly indicate to GROVER

the direction in which to turn its turret, they have priority over the front sensor.

When the area is void of targets, GROVER is free to roam. Using an ultrasonic range

finder, GROVER checks to make sure no obstacles lay in its immediate path. If the path is clear,

GROVER will update its engagement display, reset the turret to the forward position, and engage

its drive motors forward. GROVER then returns to polling the perimeter PIR sensors and

ultrasonic sensors.

When an obstacle is detected in GROVER’s immediate path, GROVER disengages both

drive motors to avoid a collision. The vehicle is then rotated 90 degrees to the right and returns

to the polling loop. The drive motors will automatically be engaged if the new path is clear and

there are no potential targets in the area by virtue of the polling loop.

The polling loop will continue until power is turned off by the RF remote or GROVER is

out of ammo. Whenever GROVER fires its weapon, the ammo count is updated to reflect the

spent munitions. If, after firing, the ammo quantity is zero, GROVER will halt and wait to be

reloaded and reset.

10.1. Software Design Narrative

GROVER’s application code consists of seven basic modules: Grover, Ultrasonic, H-

Bridge, PIR, Servo, AirSoft, and LCD. Each module contains the necessary initialization and

program code for its namesake component with the Grover module tying everything together.

10.1.1. Grover

The Grover module contains the main polling loop, grover_loop. Coming out of reset,

the application entry point is grover. It is here that all components (ultrasonic range finder, h-

bridge, PIR sensors, servo, and AirSoft gun) are initialized and variables reset. A 10 second

delay is then called for those who wish to escape GROVER’s sensor range. GROVER then

enters grover_loop and begins searching for targets. The microcontroller will remain in this loop

until it is powered down or GROVER runs out of ammunition.


-45-

10.1.2. Ultrasonic

The ultrasonic module consists of the ultrasonic initialization code as well as routines for

determining object distance. u_sonic_init properly sets the trigger pulse pin as an output and the

echo reception pin as an input. The timer subsystem is also initialized by a call to tim_ini and an

initial value for the trigger pulse output is set. Determining an object’s distance, as well as

taking any needed action, is handled by the u_sonic_ping subroutine.

The ultrasonic sensor requires that its input line, be held low (logic “0”) and then brought

high (logic “1”) for a minimum of 10µs to trigger a sonic pulse. The pulse is generated on the

falling edge of this trigger input. A start time, based on the microcontroller’s free running

counter, is stored to variable tm_start on this falling edge. A falling edge on the echo line, is

indicative of echo reception (or a timeout occurring) and the free running counter’s time is stored

to tm_end on this edge. By subtracting tm_start from tm_end, one can determine the time-of-

flight of the ultrasonic pulse (the longer the time-of-flight, the greater the object’s distance). If

the distance is within one foot, the subroutine motor_halt is called to stop the vehicle in order to

avoid a collision. GROVER can then turn to search for an obstacle free path.

10.1.3. H-Bridge

The H-Bridge module consists of initialization code as well as routines for controlling the

movement of Grover. General purpose output pins PT0 – PT3 provide signals to the H-Bridge as

to the motor/direction pairs to activate. The functions motor_halt, motor_forward, motor_right,

and motor_left set pins PT0-PT3 to attain the desired result as summarized in Table 10-2.

Stop Forward Right Turn Left Turn

PT0 0 1 1 0

PT1 0 0 0 1

PT2 0 1 0 1

PT3 0 0 1 0

Function motor_halt motor_forward motor_right motor_left

Table 10-2: H-Bridge Configuration Signals


-46-

In addition to setting the motors to turn GROVER, motor_right and motor_left call delay

loops to only enable the motors long enough to make an approximately 90-degree turn.

motor_forward and motor_halt simply set PT0 – PT3 appropriately and return.

10.1.4. PIR

The PIR module contains initialization code and polling routines for GROVER’s various

PIR sensors. pir_poll checks each of the three perimeter PIR sensors input ports sets the lower

three bits of variable pir_data to correspond to the values read. The value in variable pir_airsoft

is set based on the polling of the turret mounted narrow-range PIR sensor called by pir_poll_t.

A logic “1” signal indicates that a target has been detected. The main polling loop code

in the Grover module interprets pir_poll, while pir_airsoft is read by a Servo module subroutine

so that it knows when a target is lined up with the weaponry and to stop rotating the turret.

10.1.5. Servo

Initialization code as well as routines to incrementally change the turret’s position is

contained in the servo module. By altering the duty cycle sent to the servo’s input using the

HC(S)12’s timer module, the position of the servo (and consequently the turret) is changed.

servo_rst resets the turret so that it faces forward. servo_right and servo_left, incrementally

move the servo in fifteen degree increments in their respective directions. After the servo has

moved each increment, pir_poll_t is called to determine whether or not the turret is aligned with

its target. If it is, the servo holds its position and the weapon is fired. Otherwise, the servo

continues incrementing until it reaches its limit. At that time servo_rst is called and GROVER is

rotated 90 degrees in the direction the turret was traveling when it reached its limit. The

subroutine then returns to grover_loop so that the target’s position can be reevaluated.

10.1.6. AirSoft

The AirSoft module consists of an initialization routine and a firing routine. The

initialization routine, airsoft_init, properly configures the data direction register and sets an

initial value to the output port. The firing routine, airsoft_fire, fires a five shot burst and updates

the remaining ammunition variable, ammo.


-47-

10.1.7. LCD

The LCD module consists of the initialization routine for the LCD as well as subroutines

to update the LCD’s display. LCD_init initializes the LCD so that it will be ready for 8-bit

parallel communication with the microcontroller. PTM_init initializes the data direction registers

of Port M so that those pins may be used for SPI communication with the shift register. After

calling PTM_init, LCD_init completes the initialization process as shown in Figure 10-3.

Several other routines in the LCD module help display information on the LCD. SPIgen

generates a clock cycle and a data cycle for the SPI transmission based on the data in the variable

SPI_data. After each transmission, the data is shifted left by one and stored back in SPI_data for

the next transmission. SPI_send sends 8 bits of data through the SPI by calling SPI_gen for each

bit. send_E generates the enable pulse, E, for the LCD to signify the start of a data write

operation.

For displaying non-whitespace characters on the LCD, functions have been written to

display individual characters as well as full words. Individual character functions can display

characters such as ‘G’, ‘A’, ‘R’, ‘’, etc. while full word functions display messages such as

‘PWR ON’, ‘GROVER ARMED’, etc.

For generating white space characters, functions for displaying space, backspace, new

line, etc. were written. cursor_reset returns the LCD’s display cursor to its original position

while clear_disp clears the LCD.


-48-

10.2. Software Documentation

10.2.1 Flowcharts

Figure 10-1: Program Flow


-49-

Figure 10-2: Center Sweep

10.2.2. Listing

o See Appendix F


-50-

11.0 Version 2 Changes

• All parts surface mount

Design the PCB so that as many parts as possible can be surface mounted to make

PCB more compact.

• Bigger…better…base!

Utilize a bigger and sturdier base for the robot, so more space is available for

batteries and other peripherals.

• Fiberglass shell

Utilize fiberglass to make a better outer shell so the robot is more durable and

aesthetically more pleasant.

• Secondary control through internet

Design and add a secondary control option through wireless internet connections.

• Remotely fire gun with key fob

Design and add gun fire control using the key fob.

• Fit more to main PCB

Place and route the PCB more compactly so more peripheral circuitry such as the

H-bridge or PIR sensors could fit on the PCB.


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12.0 Summary and Conclusions

12.1 Accomplishments This semester we accomplished the complete design of an autonomous robot named

GROVER from scratch. We were able to come up with a block diagram, design a schematic,

and create a layout to form our own printed circuit board. We researched and ordered all of the

necessary parts and created a working circuit board with a microcontroller and power supplies.

Although this entire process was new to us, our circuit design turned out to be very successful.

We were able to write software to have the microcontroller communicate with 9 peripheral

devices. GROVER was able to avoid obstacles using ultrasonic sensors and detect targets

utilizing passive infrared sensors. We were able to put together a robot that had a small mind of

its own. We met all of our success criteria and therefore created an excellent project.

12.2 Lessons Learned This semester we learned several important lessons while completing our project. One

major lesson involved making sure components meet the required specifications. We found this

out quickly while working with our switching regulator circuit. This was our first experience

working with power supply designs, so we didn’t know exactly what we were doing. We placed

the parts on the PCB and tested the power supply and it seemed to work until we tested it with

the gun motor. It turns out that the inductor used as the regulator choke was only rated for 150

mA. The problem was that we were drawing almost 1 A through it at the time of explosion.

After the smoke screen cleared, we took a look at the datasheet and realized that the rating was a

little low. We won’t ever forget this lesson.

Another lesson we learned is to use consistent colors when creating wire connections for

different components. To be more specific, power and ground should be clearly marked and

kept the same color throughout the project. On at least one occasion, the colors got mixed up

and circuits were destroyed. In the end, it pays to take a little extra time to organize the wires

and keep track of what they mean. This saves a lot of headaches later on.

The biggest lesson that we learned was that teamwork can really make a project easier.

Having teammates to talk to and double check work is a very important aspect of a successful

design. This project would be very difficult for one person to do alone in a semester. Working


-52-

together and listening to each other’s ideas was very important in our project. Mistakes were

caught early causing a lot less suffering in the end.


-53-

13.0 References

[1] “ATmega32 Product Card” [Online Document], Available HTTP:

http://www.atmel.com/dyn/products/product_card.asp?part_id=2014

[2] “M68MOD9S12C32 Product Summary Page” [Online Document],

Available HTTP:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=M68MOD912C32&

parentCode=MC9S12C32&nodeId=01624684492994

[3] “MC9S12C32 Product Summary Page” [Online Document], Available HTTP:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC9S12C32&nodeI

d=01624684492994

[4] “Rolling Code 2-Channel UHF Remote Control Data Sheet” [Online Document],

Available HTTP: http://info.hobbyengineering.com/specs/DIY-k157v2.pdf

[5] “Stepper Motor Data Sheet” [Online Document], Available HTTP:

http://info.hobbyengineering.com/specs/PX-27964.pdf

[6] “Devantech SRF04” [Online Document], Available HTTP:

http://info.hobbyengineering.com/specs/devantech-srf04-tech.pdf

[7] “Devantech SRF08” [Online Document], Available HTTP:

http://info.hobbyengineering.com/specs/devantech-srf08-tech.pdf

[8] “PIR Sensors: Kitsrus K30” [Online Document], Available HTTP:

http://info.hobbyengineering.com/specs/DIY-k30.pdf

[9] ”Heath/Zenith SL-5408-WH” [Online Document], Available HTTP:

http://12.153.20.71/heath/mainProduct.asp?page=security&type=Motion+Sensing+Securi

ty+Lighting&model=SL-5408


-54-

[10] “Heath/Zenith SL-6030-WH5” [Online Document], Available HTTP:

http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?prod_id=16173

1&cm_mmc=1hd.com2msn-_-product_feed-_-D27X-_-161731

[11] “LCD: Hitachi LM044L” [Online Document], Available HTTP:

http://www.datasheetarchive.com/datasheet/pdf/17/170557.html

[12] “OPTREX DMC20261A” [Online Document], Available HTTP:

http://www.ece.unh.edu/courses/ece649/documentation/axiom/lcd_Dmcman_full.pdf

[13] “Product Web Page for Rogue ATR and Blue Base Robots” [Online Document],

Available HTTP: http://www.hobbyengineering.com/rogue.html

[14] “Roomba Reference (Height and Weight)” [Online Document], Available HTTP:

http://www.hammacher.com/publish/71545.asp?source=google&keyword=roomba&cm_

ven=NewGate&cm_cat=Google&cm_pla=Roomba%20%20&cm_ite=roomba#

[15] “Roomba Reference (General)” [Online Document], Available HTTP:

http://www.pcworld.com/news/article/0,aid,116854,00.asp

[16] “Roomba Reference (Sensors)” [Online Document], Available HTTP:

http://www.realestatejournal.com/housegarden/toolsgadgets/20021105-mossberg.html

[17] “Foster-Miller Talon brochure” [Online Document], Available HTTP:

http://www.foster-miller.com/literature/documents/TALON_Brochure.pdf

[18] “Fact Sheet: Printed Circuit Board Manufacturers” [Online Document], Available HTTP:

http://es.epa.gov/techinfo/facts/vdwm/va-fs6.html


-55-

[19] “Guides to Pollution Prevention – The Printed Circuit Board Manufacturing Industry”

[Online Document], Available HTTP: http://www.p2pays.org/ref/02/01050.pdf

[20] “Recycling Batteries” [Online Document], Available HTTP:

http://www.batteryuniversity.com/partone-20.htm

[21] “Fact Sheet: Disposal of Alkaline Batteries” [Online Document], Available HTTP:

http://es.epa.gov/techinfo/facts/pro-act5.html

[22] “Printed Circuit Board Recycling” [Online Document], Available HTTP:

http://p2library.nfesc.navy.mil/P2_Opportunity_Handbook/2_II_8.html

[23] “Household Battery Fact Sheet” [Online Document], Available HTTP:

http://www.dec.state.ny.us/website/dshm/redrecy/battery.htm

[24] “Battery Disposal” [Online Document], Available HTTP:

http://www.duracell.com/care_disposal/disposal.asp?id=62&

[25] “Aluminum Recycling” [Online Document], Available HTTP:

http://www.anchoragerecycling.com/alumfact.htm

[26] “CodeWarrior Development Studio for Freescale HC(S) 12 Microcontrollers.”

Metrowerks. Available HTTP:

http://www.metrowerks.com/MW/Develop/Embedded/HC12/Default.htm

[27] “mc9s12c32.inc” Generated by [26].

[28] “MC9S12 Family Device User Guide V01.11” [Online Document], Available HTTP:

http://www.freescale.com/files/microcontrollers/doc/data_sheet/9S12C128DGV1.pdf


-56-

[29] “OPTREX DOT MATRIX CHARACTER LCD MODULE USER’S MANUAL”

[Online Document], Available HTTP:

http://www.optrex.com/SiteImages/LitCentral/Dmcman_full.pdf

[30] “Autonomous Rolling Robot,” [Online Document], Available HTTP:

http://patft.uspto.gov/netahtml/srchnum.htm patent # 6,414,457

[31] “Mobile Robots and their Control System,” [Online Document], Available HTTP:


[32] “Method for Operating a Robot,” [Online Document], Available HTTP:


[33] “Autonomous Moving Apparatus having Obstacle Avoidance Function,” [Online

Document], Available HTTP: http://patft.uspto.gov/netahtml/srchnum.htm patent #

6,515,614

[34] “Socially Interactive Autonomous Robot,” [Online Document], Available HTTP:


[35] “United States Patent and Trademark Office” [Website], Available HTTP:

http://www.uspto.gov

[36] “ECE 477 Group 1 Project Autonomous Robot” [Online Document], Available

HTTP: http://shay.ecn.purdue.edu/~dsml/ece477/Webs/S03-Grp01/index.html

[37] “Motorola AN1259” [Online Document], Available HTTP:

http://shay.ecn.purdue.edu/%7Edsml/ece477/Homework/Spr2005/AN1259.pdf


-57-

[38] “Designing for Reliability, Maintainability, and safety” [Online Document], Available

HTTP:

http://shay.ecn.purdue.edu/~dsml/ece477/Notes/PDF/4-Mod10_ref.pdf

[39] “MILITARY HANDBOOK: RELIABILITY PREDICTION OF ELECTRONIC

EQUIPMENT” [Online Document], Available HTTP:

http://shay.ecn.purdue.edu/~dsml/ece477/Homework/Spr2005/Mil-Hdbk-217F.pdf

[40] “Linear Tech LT 1376-5 Switching Regulator Step Down Converter Datasheet” [Online

Document], Available HTTP:

http://www.linear-tech.com/pc/downloadDocument.do?navId=H0,C3,P1544,D2896

[41] “Linear Tech LT 1374-5 Switching Regulator Step Down Converter Datasheet” [Online

Document], Available HTTP:

http://www.linear-

tech.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1042,C1032,C1064,P1620,D

5227

[42] “4N28 Phototransistor Output Optocoupler Datasheet” [Online Document], Available

HTTP:

http://www.fairchildsemi.com/ds/4N/4N28.pdf

[43] “Parallax #900 servo” [Online Document], Available HTTP:

http://info.hobbyengineering.com/specs/PX-900-00005F.pdf

[44] “Low Cost H-Bridge datasheet” [Online Document], Available HTTP:

http://shay.ecn.purdue.edu/~477grp7/LCHB-100.pdf


-A1-

Appendix A: Individual Contributions A.1 Contributions of Joel Stubbs:

This semester we were given the challenge of a very open ended project to complete.

This, like many other classes at Purdue, involved the cooperation and development of a team of

people. At the start of the semester, we put together a team that we thought could work well

together and complete any task that needed to be accomplished. Throughout the semester, we

each obtained roles in the group and worked on things that we were interested in. I was chosen

to be team leader and had the opportunity to organize and lead the team as well as participate in

each part of the design and testing process. Aside from taking a leadership role, a few of my

project contributions are listed below.

One major contribution I made to our team involved the research, development, and

testing of the initial software prototyping and communication for the ultrasonic module and the

servo. I knew that it would take some time to get back into the routine of writing assembly and

communicating with the microcontroller. Early in the semester, I borrowed one of the old

Motorola 68HC12 development boards to work with. I tested some old code from EE362 and

relearned some assembly language. After I became familiar with it again, I researched how the

ultrasonic module worked. I learned about the special communication and timing of the system.

I then wrote some software to test the measurement of distances from objects. I did the same

thing with the servo. I found out that it needed a 1.5 ms pulse to face forward and used pulses

plus or minus 0.5 of that to change to other directions. I again wrote some test software and

tested the operation of the servo. Both of these were in working order for when we needed them

later on in the semester.

Another major contribution I made involved the development and testing of the gun opto-

isolator circuit. This is something that I was very interested in. The firing of the gun was crucial

to our project’s success. Therefore, this was done almost immediately after receiving the AirSoft

machine gun in the mail. I looked through some old EE362 notes and found a circuit used to

control a motor. This circuit involved an active low output pin from the microcontroller. An

optical isolator was used to isolate the output pin from the motor. This circuit also contained an


-A2-

arc suppression diode to keep any current spikes from damaging the circuit. This circuit turned

out to work very well for firing the automatic electric machine gun.

Some other major contributions involved populating the PCB with components, helping

debug hardware and software, and developing packaging. The PCB was something that we put

together as soon as we received it. We were in the lab the night that it arrived and were able to

solder it together in a very timely fashion. I was also in charge of creating all of the wire

harnesses for each interface connection. This was a very tedious job especially when some of

the connections required the crimping of 16 wires on both ends. Having bad wire connections

was something we didn’t need to deal with, so I made sure that every single wire in each bus was

connected very tightly. I performed continuity tests on each wire after the creation of each bus.

These busses made it very easy to connect each component to its corresponding header on the

PCB.

Once the main software started being developed, it was time to start completing the

packaging. I was able to contribute key ideas to the packaging scheme and I started building up

temporary packaging for testing purposes. We didn’t have all of the mounting hardware at first,

so we pulled together some stuff from around the lab to test the servo, ultrasonic, and gun

software. To test all of these together, we had to have somewhat of a working package for the

robot. I assisted in debugging the software with Andrew once we had working packaging put

together.

Overall, I think each team member played an important role in our project. Everybody

contributed their part and I think the tasks were pretty evenly divided. I think everybody worked

very well together and that made it pretty easy to pull together a working project. After

demonstrating all of our success criteria, I feel that we had a very successful team and that

everybody deserves an ‘A’.


-A3-

A.2 Contributions of Stan Miller: This past semester I have really enjoyed ECE 477 because of the freedom you are

allowed in creating your project. I believe Team GROVER did an outstanding job working

together and getting everything done ahead of schedule. Below is an overview of what I feel I

contributed to the group this past semester.

My main focus this semester was the printed circuit board and overall packaging design.

I was the only electrical engineer in the group so my contributions to software design and testing

would be minimal. I wanted to make sure I was putting in my fair share of work in the hardware

and packaging areas and I feel I accomplished that. For the printed circuit board I spent a

majority of my time finding/creating footprints, untangling “rubber bands”, placing the parts

where they would work the best, and finally routing. This process took a total of about 50 man

hours included the other team members’ time. I designed 3 different boards because the first two

had fatal errors and it was just easier to start over. Overall, our board was fairly simplistic, but I

put a fair amount of time into this part of the design.

The contribution that I had the most fun with this semester was the overall packaging of

GROVER. To start off I built the motors that moved the tank. I ended up having to build the

motor 2 different ways because we first built it for high-speed, low-torque, but as the project

moved on and weight was added, I had to go back and rebuild for higher torque. I was also in

charge of mounting the servo, the gun, and the turret, which was just 2 wall mounts screwed

together. At the end of the project we needed to fix the center of gravity so using L-brackets I

mounted the batteries to the side of the tank and the PIR 9-volt batteries to the top. I also

dropped a level down and mounted the LCD to the top level using 4 L-brackets and made it more

user-friendly.

I was also tasked with the Patent Liability Analysis which consisted of finding patents

using the United States Patent and Trademark Website. I found patents that our project possibly

infringed upon either literally or through the doctrine of equivalents.

I thoroughly enjoyed my time with Team GROVER and I believe we did an overall

outstanding job this semester. I have learned a lot and hope to keep designing in the future.


-A4-

A.3 Contributions of Andrew Parcel:

With the exception of the LCD module, I wrote, commented, tested, and debugged the

final application software. This consists of the main polling loop as well as the servo, ultrasonic,

PIR, H-bridge, and AirSoft modules. Based on the preliminary interfacing work done with Joel

on the evaluation board, I modified the code to work with our HC(S)12 derivative and added

functionality. For instance, during our preliminary work, we were able to determine the extent to

which we could turn the servo left and right. I took this knowledge and created the algorithms

for incrementally stepping the servo and looking for the presence of targets. If the servo’s limit

was reached without having found a valid target, GROVER would reset its turret, turn its base 90

degrees in the last known direction of the target, and re-evaluate its perimeter sensors to find the

target.

Having designed the overall program flow and written the overwhelming majority of the

application code, completion of the Software Design Consideration homework wasn’t overly

challenging. I wrote the Ethical and Environmental Analysis homework and contributed heavily

in group assignments (proposals, presentations, user manual, final report) as well. I also served

as an unofficial editor, offering grammatical corrections and phraseology suggestions to other

members in my group.

During our first integration test, we found that the PIR sensors were too sensitive for their

intended use. In addition, when a target was detected by the sensor, it would output a logic ‘1’

signal for 6-8 seconds. Having to constantly wait to ensure we were using up-to-date data before

firing was unacceptable. I came up with fixes for both problems. In our final design,

GROVER’s PIR sensors were susceptible to “body mass,” but not lights or hands. Also, the

length of the asserted PIR output was reduced to less than a second. This shifted the burden of

acquiring up-to-date data to software, which was preferable. Furthermore, I soldered and helped

place the PIR sensor mounted inside the AirSoft gun.

I was also heavily involved with the preliminary packaging. I handled the placement of

the perimeter PIR sensors and ultrasonic sensor. I worked with Joel on determining the best


-A5-

placement of the H-bridge and RF switch. Joel, Edwin, and I also worked on getting the board

populated in one night.

Early in the semester, I created the team’s website and designed the associated

graphics/logos. In lieu of programs such as FrontPage and Dreamweaver, I used the same type

of program I created my first web page on in 1996 to create the team’s website: a text editor. In

addition to creating basic lab notebooks for the team members to use, I also wrote a Python script

to generate printable views of the notebooks. Edwin and I shared photographing duties. We

each took pictures of GROVER documenting the evolution from individual components and a

bare circuit board to a complete and functional system.


-A6-

A.4 Contributions of Edwin Tjandranegara:

My contributions to this project varied vastly across different disciplines and knowledge.

I was in charge of the project schematic design, software design and interfacing of the LCD and

shift register, reliability and safety analysis, and H-bridge and PIR sensors interfacing. I also

helped Andrew with his webmaster duties.

Due to my circuit design responsibilities, I was the person responsible for selecting power

supply chips and designing the power supply circuitry. I’m very proud of my schematic design.

It only underwent two revisions and both revisions are just minor additions to the schematic.

Since I created and designed the schematic, it only made sense if I was involved largely in

selecting and ordering components. I was also able to help Stan in creating and matching layout

footprints with the actual components.

I was also responsible for interfacing the MCU with the shift register/LCD in order to

display data on the LCD. Although never formally assigned this task, I decided to do it to ease

Andrew’s burden in writing the software. I had initially planned to only start the software and

let others build upon my work, but the more I tried to do it, the more fun I had. I ended up

finishing the entire LCD module. I also created a few subroutines that Andrew could call to

display data to the LCD.

I was the person in charge of initially interfacing the H-bridge and the PIR sensors. I also

assembled all five PIR sensors. I helped Andrew maintain and update the website as well. I had

a lot of fun doing this because I learned how to use Macromedia Dreamweaver. I also did a lot

of other chores like editing the demo clips, created presentation slides, and cleaning up the

workbench whenever we were done for the day.

I definitely learned a lot of new things regarding circuit design and electronic design in

general by taking this class. I am sure that the new skills I gained from this class will be very

useful in the future.


B-1

Appendix B: Packaging

Figure B-1: Final Packaging of GROVER – Front/Side View


B-2

Figure B-2: Final Packaging of GROVER – Top View


C-1

Appendix C: Schematic C-1 OrCAD schematic

Figure C-1: OrCAD Schematic of GROVER


C-2

C-2 OrCAD design rule check report

Checking Pins and Pin Connections

--------------------------------------------------

Checking Schematic: SCHEMATIC1

--------------------------------------------------

Checking Electrical Rules

Checking for Unconnected Nets

Checking for Invalid References

Checking for Duplicate References

Reporting Ports

Reporting Off-Page Connections

Reporting Globals

0

Checking Visible Unconnected Power Pins

Check Bus width mismatch

C-3 OrCAD bill of materials report

GROVER - Schematic Revised: Thursday, March 03, 2005

ECE477SP05 - GRP7 Revision: 1v0

ECE477 Group 7 Sp 2005

Purdue University - West Lafayette, IN

Bill Of Materials March 3,2005 14:06:06 Page1

Item Quantity Reference Part

______________________________________________

1 2 C4 0.01 uF

C5 0.01 uF

2 1 C6 22 uF

3 1 C7 1.5 nF

4 1 C8 0.27 uF

5 2 C9 100 uF, 10V Solid Tantalum

C13 100 uF, 10V solid tantalum

6 1 C10 33 uF


C-3

7 1 C11 3.3 nF

8 1 C12 0.1 uF

9 1 D2 MBRS330T3

10 1 D3 CMDSH3

11 1 D4 1N4001

12 1 D5 1N5818

13 1 D6 1N914

14 2 D7 LED

D9 LED

15 2 J1 HEADER for debug

J2 HEADER for debug

16 1 J3 VIN

17 4 J6 HEADER to PIR

J7 HEADER to PIR

J8 HEADER to PIR

J9 HEADER to PIR

18 2 J11 Battery

J17 Battery

19 1 J12 Gun Battery

20 1 J14 Header Gun

21 1 J15 CAN HEADER

22 1 J16 5V, 4.25A

23 1 J18 5V, 1.25A

24 1 J19 HEADER 7X2

25 1 J20 DIPSOC-16x2

26 1 J21 HEADER to Servo

27 1 J22 HEADER to Hbridge

28 1 J23 HEADER to Usonic

29 2 L2 10 uH

L3 10 uH

30 1 Q1 TIP122

31 5 R1 1K

R3 1K

R5 1K

R7 1K

R17 1K

32 5 R2 1.2K

R4 1.2K

R6 1.2K

R8 1.2K

R13 1.2K

33 1 R12 2.2K

34 1 R16 220

35 1 R18 10K

36 1 SW1 RESET

37 1 SW2 SW KEY-SPST

38 1 U3 74HC164

39 1 U5 LT1374-5/SO

40 1 U6 4N28

41 1 U7 LT1376/SO8

42 1 W1 JUMPER1


D-1

Appendix D: PCB Layout Top and Bottom Copper

Figure D-1: Top layer of PCB


D-2

Figure D-2: Bottom layer of PCB


E-1

Appendix E: Parts List Spreadsheet

Part Vendor Part Number Unit Cost Quantity Final Cost

Micro-Controller Motorola M68MOD912C32 $24.95 1 $24.95

PIR Motion Detector

Kitsrus K30 $20.95 4 $83.80

H-Bridge Rogue Robotics LCHB $0.00 1 $ 0.00

Ultrasonic Range Finder

Devantech SRF04 $33.50 1 $33.50

Robot Base Rogue Robotics RT-ATR $139.95 1 $139.95

Robot Extra Level Kit

Rogue Robotics RT-XLV $29.95 1 $29.95

LCD Optrex Corporation

DMC20261A $0.00 1 $0.00

Airsoft/Paintball Gun

KTC 210910 $18.50 1 $18.50

RF switch Kitsrus K157-A $45.95 1 $45.95

Servo Parallax Inc JR NES-537 $23.00 1 $23.00

30V Schottky Diodes

Central Semi 610-CMDSH-3

$0.66

1 $0.66

Switching regulator

Linear Tech LT1376-5 $4.35 1 $4.35

Switching regulator

Linear Tech LT1374-5 $5.00 1 $5.00

8-Bit SIPO Shift Reg

ST 5V Logic

511-M74HC164

$0.71

1 $0.71

10 uH inductor API Delevan 2474-13L $2.70 1 $2.70

BR/BK/BK/SL 10UH inductor

J.W. Miller 77F100K $0.55 1 $0.55

DIODE SCHOTTKY 30V 3A SMC

Central Semi MBRS330T3OSCT-ND

$0.34

1 $0.34

OPTOCOUPLER TRANS-OUT 6-DIP

National Semi 4N28-ND $0.52 1 $0.52

TRANS NPN DARL 100V 5A

National Semi TIP122FS-ND $0.60 1 $0.60


E-2

TO-220

Resistors, Capacitors, switches and misc. Diodes

- - - - $30.00

Batteries & Chargers

- - - - $50.00

Total $544.53

Table E-1: Major Components Spreadsheet


F-1

Appendix F: Software Listing ;*****************************************************************

;*****************************************************************

;* GROVER *

;*****************************************************************

;*****************************************************************

; export symbols

XDEF Entry ; export 'Entry' symbol

ABSENTRY Entry ; for absolute assembly:

; mark this as application entry

; point

; include derivative specific macros

INCLUDE 'mc9s12c32.inc'

ROMStart EQU $4000 ; absolute address to place

; code/constant data

ORG RAMStart

;**************************************************************

; Variables

;**************************************************************

start_tm fdb 2 ; echo start time

end_tm fdb 2 ; echo end time

pir_data rmb 1 ; perimeter pir trigger data

pir_airsoft rmb 1 ; turret pir trigger data

ammo rmb 1 ; ammo count

engage rmb 1 ; engagement count

e_flag rmb 1 ; engagment flag

SPI_data rmb 1

BIN_data rmb 1

ORG ROMStart

Entry:

;**************************************************************

;* Grover Project Code *

;**************************************************************

;bra Test

grover

lds #$0FFF ; initialize stack pointer

ldaa #$00 ; disable cop watchdog

staa COPCTL

; initializations

jsr motor_init ; initialize h_bridge

jsr servo_init ; initialize servo

jsr u_sonic_init ; initialize ultrasonic sensor

jsr pir_init ; initialize pir sensors

jsr airsoft_init ; initialize air_soft

jsr LCD_init ; initialize lcd display

jsr LCD_power ; display power on message

; reset variables

movb #$00,engage ; reset engagement count

movb #$00,e_flag ; reset engagement flag

movb #20t,ammo ; reset ammo count

movb #$00,pir_data ; reset perimeter pir flag

movb #$00,pir_airsoft ; reset turret pir flag

; reset turret


F-2

jsr servo_rst ; make sure gun is facing forward

; pause for 10 seconds

jsr delay2_5s

jsr delay2_5s

jsr delay2_5s

jsr delay2_5s

grover_loop

nop ; poll pir sensors 26 times

ldx #$1A ; load x with 26

poll_loop

jsr delay20ms ; 20ms delay

jsr pir_poll ; poll pir sensors

ldaa pir_data

lbne target_det ; if sensors report a target, branch

dbne x,poll_loop ; if x != 0, continue pir polling loop

jsr u_sonic_ping ; otherwise, check for obstacles

lbra grover_loop ; continue infinite loop

target_det

jsr motor_halt ; if target detected, stop moving

ldaa pir_data ; check whether or not the right-side

anda #%00000100 ; pir sensor was triggered and

bne target_right ; branch to target_right if true

ldaa pir_data ; check whether or not the left-side


bne target_left ; branch to target_left if true

ldaa pir_data ; check whether or not the center


bne target_center ; branch to target_center if true

lbra grover_loop ; otherwise, branch back to the main loop

target_right

jsr servo_right ; start looking for the target on the right

jsr delay20ms ; pause 40ms before returning to the main loop

jsr delay20ms

lbra grover_loop

target_left

jsr servo_left ; start looking for the target on the left


jsr delay20ms

lbra grover_loop

target_center

jsr center_sweep ; start center sweep


jsr delay20ms

lbra grover_loop

;**************************************************************

;* Test Loops *

;**************************************************************

;* FOR DEVELOPMENT PURPOSES ONLY *

;**************************************************************

Test

lds #$0FFF ; initialize stack pointer

ldaa #$00 ; disable cop watchdog

staa COPCTL


jsr LCD_init

jsr LCD_power

jsr delay2_5s

nop


F-3

jsr airsoft_init ; initialize airsoft gun

nop

jsr airsoft_fire ; fire a 5-shot burst

jsr delay2_5s

jsr delay2_5s

jsr delay2_5s

jsr delay2_5s

Test_loop

jsr servo_right ; move servo right to left

jsr delay2_5s

jsr delay2_5s

jsr servo_left

jsr airsoft_fire

jsr delay2_5s

jsr delay2_5s

nop

bra Test_loop

stop

;**************************************************************

;* AirSoft *

;**************************************************************

;* Pin: PM0 - active low output to gun *

;**************************************************************

;--------------------------------------------------------------

; airsoft_init

;--------------------------------------------------------------

; Description: Sets the data direction of PM0 to output and

; sets PM0's initial value to 1

;--------------------------------------------------------------

airsoft_init

pshd

pshc

ldaa #%00111101 ; set PM0 as output

oraa DDRM

staa DDRM

;PREDATOR CODE FIX!

ldaa #%00000001 ; set PM0's initial value

oraa PTM ; to 1

staa PTM

pulc

puld

rts

;--------------------------------------------------------------

; airsoft_fire

;--------------------------------------------------------------

; Description: Fires a 5-shot burst from the AirSoft gun

;--------------------------------------------------------------

airsoft_fire

pshd

pshc

ldaa PTM ; fire gun

anda #$FE

staa PTM

jsr delay2_5s ; wait about 5 seconds

jsr delay2_5s ; (equivalent to 5 shots)

ldaa PTM ; cease fire

oraa #$01

staa PTM

ldaa ammo ; update the ammo count

suba #$05

staa ammo

ldaa ammo ; check whether or not GROVER


F-4

suba #$00 ; is out of ammo

beq out_of_ammo

movb #$FF, e_flag ; set engagement flag

pulc

puld

rts

out_of_ammo

nop ; if out of ammo, display reload

jsr cursor_reset ; message and enter infinite loop

jsr Disp_POWER_ON_STNBY

i_loop nop

bra i_loop

stop

;--------------------------------------------------------------

; airsoft_test

;--------------------------------------------------------------

; Description: Initializes the AirSoft gun and fires 5-shot

; bursts followed by 10 seconds of cease fire in

; a loop

;--------------------------------------------------------------

airsoft_test

jsr airsoft_init

airsoft_test_l

jsr airsoft_fire ; fire a 5-shot burst

jsr delay2_5s ; wait about 10 seconds

jsr delay2_5s

jsr delay2_5s

jsr delay2_5s

bra airsoft_test_l

;**************************************************************

;* PIR Sensors *

;**************************************************************

;* Pin: AN0 - PIR 1 input - Left Side *

;* AN1 - PIR 2 input - Front *

;* AN2 - PIR 3 input - Right Side *

;* AN3 - PIR 4 input - Turret *

;**************************************************************

;--------------------------------------------------------------

; pir_init

;--------------------------------------------------------------

; Description: Sets the data direction of AN00 - AN03 as

; inputs and clear pir_data and pir_airsoft

;--------------------------------------------------------------

pir_init

pshd

pshc

ldaa #$F0 ; set AN0 - AN3 as inputs

anda DDRAD

staa DDRAD

movb #$FF,ATDDIEN

movb #$00,pir_data ; clear pir_data

movb #$00,pir_airsoft ; clear pir_airsoft

pulc

puld

rts

;--------------------------------------------------------------

; pir_poll

;--------------------------------------------------------------

; Description: Poll PIRs 1, 2, and 3 and store the data in

; bits 0, 1, and 2 of the variable pir_data

;--------------------------------------------------------------

pir_poll


F-5

pshd

pshc

ldaa PTAD ; get PIR data from PIRs

anda #$07 ; 1, 2, and 3 and store in

staa pir_data ; pir_data

pulc

puld

rts

;--------------------------------------------------------------

; pir_poll_t

;--------------------------------------------------------------

; Description: Poll the PIR sensor on the turret and store the

; data in bit 3 of the variable, pir_airsoft

;--------------------------------------------------------------

pir_poll_t

pshd

pshc

ldaa PTAD ; get PIR data from PIR 4

anda #$08 ; and store in pir_airsoft

staa pir_airsoft

pulc

puld

rts

;**************************************************************

;* Servo *

;**************************************************************

;* Pin: PT4 - Output duty cycle to control servo rotation *

;* *

;**************************************************************

;--------------------------------------------------------------

; servo_init

;--------------------------------------------------------------

; Description: Sets the data direction of PT4 as an output and

; initialize the value to 0

;--------------------------------------------------------------

servo_init

pshd

pshc

ldaa #$10 ; set PT4 as an output

oraa DDRT

staa DDRT

ldaa PTT ; set PT4 to 0

anda #$EF

staa PTT

pulc

puld

rts

;--------------------------------------------------------------

; servo_rst

;--------------------------------------------------------------

; Description: Resets the servo so that it is facing forward

;--------------------------------------------------------------

servo_rst

pshx

pshy

pshc

ldx #20t

servo_rst_l


oraa #$10

staa PTT

jsr delay1_5ms ; keep PT4 high for 1.5ms


F-6


anda #$EF

staa PTT

jsr delay20ms

dbne x,servo_rst_l

pulc

puly

pulx

rts

;--------------------------------------------------------------

; servo_right

;--------------------------------------------------------------

; Description: Turns the turret left until a target is

; detected or the turning limit is reached.

;

; If a target is detected, call airsoft_fire.

;

; If the turning limit is reached, call servo_rst

; and turn GROVER 90 degrees to the right and

; return

;--------------------------------------------------------------

servo_right

pshx

pshy

pshc

ldd #1755t ; initial time value

servo_right_i

ldx #10t

addd #240t

pshd

puly

pshd

servo_right_l


oraa #$10

staa PTT

pshy

jsr delay_turn

puly


anda #$EF

staa PTT

jsr delay20ms

dbne x,servo_right_l

; poll turret pir sensor 10 times

; if a target is detected, branch to airsoft_fire

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms


F-7

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

; if the servo's limit is reached, branch

; to the right servo limit routine

puld

pshd

subd #3195t

beq servo_limit_r

; otherwise, continue executing the servo

; stepping routine

puld

lbra servo_right_i

servo_limit_r

nop ; reset the turret to the

jsr servo_rst ; forward position

nop

jsr motor_right ; turn GROVER 90 degrees to

nop ; the right

puld

pulc

puly

pulx

rts

servo_fire

jsr airsoft_fire ; fire the gun

jsr servo_rst ; reset the turret to the

nop ; forward position

puld

pulc

puly

pulx

rts

;--------------------------------------------------------------

; servo_left


F-8

;--------------------------------------------------------------

; Description: Turns the turret right until a target is

; detected or the turning limit is reached.

;


;

; If the turning limit is reached, call servo_rst

; and turn GROVER 90 degrees to the left and

; return

;--------------------------------------------------------------

servo_left

pshx

pshy

pshc


servo_left_i

ldx #10t

subd #219t

pshd

puly

pshd

servo_left_l


oraa #$10

staa PTT

pshy

jsr delay_turn

puly


anda #$EF

staa PTT

jsr delay20ms

dbne x,servo_left_l



ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD


F-9

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

; if the servo's limit is reached, branch

; to the left servo limit routine

puld

pshd

subd #900t

beq servo_limit_l

; otherwise, continue executing the servo

; stepping routine

puld

lbra servo_left_i

servo_limit_l



nop

jsr motor_left ; turn GROVER 90 degrees to

nop ; the left

puld

pulc

puly

pulx

rts

;--------------------------------------------------------------

; center_sweep

;--------------------------------------------------------------

; Description: Turns the turret right approximately 30 degrees,

; resets the turret, and then turns the turret

; left approximately 30 degrees. All the while,

; it is looking for a target

;


;

; If sweep completes without locating a target,

; call servo_rst and return

;--------------------------------------------------------------

center_sweep

nop

sweep_right

pshx

pshy

pshc


sweep_right_i

ldx #10t

addd #240t

pshd


F-10

puly

pshd

sweep_right_l


oraa #$10

staa PTT

pshy

jsr delay_turn

puly


anda #$EF

staa PTT

jsr delay20ms

dbne x,sweep_right_l



ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms


F-11

; if the sweep's right limit is reached, branch

; to the sweep right limit routine

puld

pshd

subd #2235t

beq sweep_limit_r

; otherwise, continue executing the sweep

; stepping routine

puld

lbra sweep_right_i

sweep_limit_r



jsr sweep_left

puld

pulc

puly

pulx

rts

sweep_left

pshx

pshy

pshc


sweep_left_i

ldx #10t

subd #219t

pshd

puly

pshd

sweep_left_l


oraa #$10

staa PTT

pshy

jsr delay_turn

puly


anda #$EF

staa PTT

jsr delay20ms

dbne x,sweep_left_l



ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms


F-12

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

ldaa PTAD

anda #$08

lbne servo_fire

jsr delay20ms

jsr delay20ms

; if the sweep's right limit is reached, branch

; to the sweep right limit routine

puld

pshd

subd #1776t

beq sweep_limit_l

; otherwise, continue executing the sweep

; stepping routine

puld

lbra sweep_left_i

sweep_limit_l



puld

pulc

puly

pulx

rts

;--------------------------------------------------------------

; servo_test

;--------------------------------------------------------------

; Description: Initializes the servo and moves it from left to

; right in a loop

;

; NOTE: Must disble target acquisition and turning code

; in servo_left and servo_right to use

;--------------------------------------------------------------

servo_test


jsr servo_rst ; move servo to the front

nop

servo_test_l

jsr servo_left ; increment servo to the left

nop


F-13

jsr servo_right ; increment servo to the right

nop

bra servo_test_l

;**************************************************************

;* Ultrasonic Sensor *

;**************************************************************

;* Pin: PT6 - input - Echo *

;* PT7 - output - Trigger *

;**************************************************************

;--------------------------------------------------------------

; u_sonic_init

;--------------------------------------------------------------

; Description: Initializes the timer and sets the data

; direction of PT7 to output, PT6 to input, and

; sets PT7's initial value to 0

;--------------------------------------------------------------

u_sonic_init

jsr tim_ini ; initialize timer subsystem

ldaa #$80 ; set PT7 as an output

oraa DDRT

staa DDRT

ldaa #$BF ; set PT6 as an input

anda DDRT

staa DDRT


anda #$7F

staa PTT

rts

;--------------------------------------------------------------

; u_sonic_ping

;--------------------------------------------------------------

; Description: Determines the distance of an object. If an

; object is in GROVER's immediate path, it halts

; the vehicle and spins it 90 degrees to the

; right and returns. If the path is clear, it

; updates the engagement count, clears the

; engagement flag, and turns the motors on for

; forward movement before returning

;--------------------------------------------------------------

u_sonic_ping

pshd

pshc

ping_loop

jsr delay2_5s

movw #$0000,start_tm ; clear start time

movw #$0000,end_tm ; clear end time


oraa #$80

staa PTT

jsr delay11us ; wait for 11 microseconds


anda #$7F

staa PTT

ping_wait1

ldaa PTT

anda #$40

cmpa #$40

bne ping_wait1

ldd TCNT

std start_tm

ping_wait2

ldaa PTT

anda #$40


F-14

cmpa #$00

bne ping_wait2

ldd TCNT

std end_tm

subd start_tm

cpd #$04dd

lbls ping_object

; check if engagement flag set

; if true, increment engagement count

; and clear flag

jsr back_space

ldaa e_flag

beq no_update

ldaa engage

adda #$01

staa engage

staa BIN_data

jsr send_num

no_update

movb #$00, e_flag

jsr motor_forward ; engage motors forward

nop

pulc

puld

rts

ping_object

jsr motor_halt ; turn off motors

jsr delay2_5s ; allow for robot to come to a

; halt

jsr motor_right ; turn robot 90 degrees right

pulc

puld

rts

;**************************************************************

;* Motors/H-Bridge *

;**************************************************************

;* Pin: PT0 - output - Motor 1 Forward *

;* PT1 - output - Motor 1 Reverse *

;* PT2 - output - Motor 2 Forward *

;* PT3 - output - Motor 2 Reverse *

;**************************************************************

;--------------------------------------------------------------

; motor_init

;--------------------------------------------------------------

; Description: Sets the data direction of PT0 - PT3 to output

; and sets their initial values to 0

;--------------------------------------------------------------

motor_init

pshd

pshc

ldaa #$0F ; set PT0-PT3 as outputs

oraa DDRT

staa DDRT

ldaa PTT ; set PT0-PT3 to 0

anda #$F0

staa PTT

pulc

puld

rts

;--------------------------------------------------------------

; motor_halt


F-15

;--------------------------------------------------------------

; Description: Turns off Motor 1 and Motor 2

;--------------------------------------------------------------

motor_halt

pshd

pshc

ldaa PTT

anda #$F0 ; kill both motors

staa PTT

pulc

puld

rts

;--------------------------------------------------------------

; motor_forward

;--------------------------------------------------------------

; Description: Turns on Motor 1 Forward and Motor 2 Forward

;--------------------------------------------------------------

motor_forward

pshd

pshc

ldaa PTT ; set both motors forward

anda #$F0

oraa #$FA

staa PTT

pulc

puld

rts

;--------------------------------------------------------------

; motor_left

;--------------------------------------------------------------

; Description: Turns Grover approximately 90 degrees to the

; right

;--------------------------------------------------------------

motor_left

pshd

pshc

ldaa PTT ; set motor 1 forward and

anda #$F0 ; motor 2 reverse

oraa #$F9

staa PTT

jsr delay2_5s ; wait approximately 5 seconds

nop

jsr delay2_5s

nop

jsr motor_halt ; stop both motors

pulc

puld

rts

;--------------------------------------------------------------

; motor_right

;--------------------------------------------------------------

; Description: Turns Grover approximately 90 degrees to the

; left

;--------------------------------------------------------------

motor_right

pshd

pshc

ldaa PTT ; set motor 1 reverse and

anda #$F0 ; motor 2 forward

oraa #$F6

staa PTT

jsr delay2_5s ; wait approximately 5 seconds

nop


F-16

jsr delay2_5s

nop

jsr motor_halt ; stop both motors

pulc

puld

rts

;**************************************************************

;* Timer Initialization *

;**************************************************************

tim_ini

movb #$80,TFLG2

movb #$80,TSCR1 ; Enable timer

movb #$00,TCTL1 ; disable capture

movb #$00,TCTL2

movb #$00,TCTL3

movb #$00,TCTL4

movb #$00,TIE

movb #$02,TSCR2 ; Set prescale factor to 8, enable

rts ; counter reset after OC7

;**************************************************************

;* LCD Stuff *

;**************************************************************

;* *

;**************************************************************

LCD_power

pshc

jsr wait15ms

jsr wait15ms

jsr Disp_POWER_ON_ARMED

jsr new_line

jsr Disp_ENG

ldaa #$00

staa BIN_data

jsr send_num

pulc

rts

LCD_test_loop

jsr back_space

ldaa #$00

staa BIN_data

jsr send_num

jsr wait15ms

jsr wait15ms

jsr back_space

ldaa #$01

staa BIN_data

jsr send_num

jsr wait15ms

jsr wait15ms

bra LCD_test_loop

stop

Disp_POWER_ON_ARMED

jsr Disp_PWR_ON

jsr arrow

jsr Disp_GROVER_ARMED

rts

Disp_POWER_ON_STNBY

jsr Disp_PWR_ON

jsr arrow


F-17

jsr Disp_RELOAD_STNBY

rts

;--------------------------------------------------------------

; word display functions

;--------------------------------------------------------------

Disp_PWR_ON

jsr letter_P

jsr letter_W

jsr letter_R

jsr colon

jsr space

jsr letter_O

jsr letter_N

rts

Disp_GROVER_ARMED

jsr letter_G

jsr letter_R

jsr letter_O

jsr letter_V

jsr letter_E

jsr letter_R

jsr space

jsr letter_A

jsr letter_R

jsr letter_M

jsr letter_E

jsr letter_D

rts

Disp_RELOAD_STNBY

jsr letter_R

jsr letter_E

jsr letter_L

jsr letter_O

jsr letter_A

jsr letter_D

jsr space

jsr letter_S

jsr letter_T

jsr letter_N

jsr letter_B

jsr letter_Y

rts

Disp_ENG

jsr letter_E

jsr letter_N

jsr letter_G

jsr colon

jsr space

rts

;--------------------------------------------------------------

; char functions

;--------------------------------------------------------------

letter_P

ldaa #%01010000 ;send P

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E


F-18

jsr wait15ms

rts

letter_W

ldaa #%01010111 ;send W

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_R

ldaa #%01010010 ;send R

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_O

ldaa #%01001111 ;send O

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_N

ldaa #%01001110 ;send N

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_E

ldaa #%01000101 ;send E

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_G

ldaa #%01000111 ;send G

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E


F-19

jsr wait15ms

rts

letter_V

ldaa #%01010110 ;send V

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_A

ldaa #%01000001 ;send A

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_M

ldaa #%01001101 ;send M

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_D

ldaa #%01000100 ;send D

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_L

ldaa #%01001100 ;send L

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_S

ldaa #%01010011 ;send S

staa SPI_data

jsr SPI_send

jsr wait15ms


F-20

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_T

ldaa #%01010100 ;send L

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_B

ldaa #%01000010 ;send L

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

letter_Y

ldaa #%01011001 ;send L

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

send_num

jsr bin2disp

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

arrow

ldaa #%01111110 ;send arrow

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

space

ldaa #%00100000 ;send :space

staa SPI_data


F-21

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

colon

ldaa #%00111010 ;send colon

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%00001000

oraa PTM

staa PTM

jsr send_E

jsr wait15ms

rts

back_space

ldaa #%00010000 ;send backspace

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

jsr wait15ms

rts

new_line

ldaa #%11000000 ;send new line

staa SPI_data

jsr SPI_send

jsr wait15ms

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

jsr wait15ms

rts

;**************************************************************

;* LCD *

;**************************************************************

;* Pin: PM5 - SCK *

;* PM4 - Data *

;* PM3 - RS *

;* PM2 - E *

;* *

;**************************************************************

PTM_init

psha

ldaa #%00111100

oraa DDRM

staa DDRM

pula

rts

; synthetic SPI: load data you want to push data you want to SPI_data


F-22

; (8bit)with format: 765432310

;--------------------------------------------------------------

; SPI Stuff

;--------------------------------------------------------------

SPI_send

pshx

pshy

psha

ldx #8t

loop

jsr SPIgen

dbne x, loop

pula

puly

pulx

rts

SPIgen

pshd

pshy

ldaa SPI_data

psha

lsla

staa SPI_data

pula

lsra

lsra

lsra

anda #%00010000

oraa #$01

staa PTM

jsr clkdelay

ldaa #%00100000

oraa PTM

staa PTM

jsr clkdelay

nop

nop

puly

puld

rts

clkdelay

pshx

pshy

pshc

ldy #1t

loopo

dbne y,loopo

pulc

puly

pulx

rts

;--------------------------------------------------------------

; LCD Initialization

;--------------------------------------------------------------

LCD_init

jsr wait15ms ;wait for 15ms



ldaa #%00110000 ;send 1st init command

staa SPI_data

jsr SPI_send


F-23

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

jsr wait15ms ;wait for 15 ms

ldaa #%00110000 ;send 2nd init command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

jsr wait15ms

ldaa #%00110000 ;send 3rd init command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

ldaa #%00111100 ;send funct set command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

ldaa #%00001000 ;send disp off command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

ldaa #%00000001 ;send clear disp command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

ldaa #%00000110 ;send entry mode set command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

ldaa #%00001100 ;send disp on command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

send_E

jsr wait15ms

ldaa #%00000100

oraa PTM

staa PTM

jsr wait15ms

ldaa #%11111011

anda PTM

staa PTM

jsr wait15ms


F-24

rts

;--------------------------------------------------------------

; Convert binary to display

;--------------------------------------------------------------

bin2disp

psha

ldaa BIN_data

oraa #%00110000

staa SPI_data

pula

rts

;--------------------------------------------------------------

; Scroll display

;--------------------------------------------------------------

scroll_disp

ldaa #%00011000 ;send scroll to left command

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

jsr wait15ms

jsr wait15ms

jsr wait15ms

rts

;--------------------------------------------------------------

; Function to return cursor to original position

;--------------------------------------------------------------

cursor_reset

ldaa #%10000000 ;send cursor reset

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

rts

;--------------------------------------------------------------

; Function to return cursor to original position

;--------------------------------------------------------------

clear_disp

ldaa #%00000001 ;send clear LCD

staa SPI_data

jsr SPI_send

ldaa #%11110111

anda PTM

staa PTM

jsr send_E

rts

;==============================================================

; Delay Loops

;==============================================================

;--------------------------------------------------------------

; 11us Delay

;--------------------------------------------------------------

delay11us

pshx

pshy

pshc


F-25

ldy #1t

loopo11us

ldx #10t

loopi11us

dbne x,loopi11us

dbne y,loopo11us

pulc

puly

pulx

rts

;---------------------------------------------------------------

; 2.5s Delay

;--------------------------------------------------------------

delay2_5s

pshx

pshy

pshc

ldy #400t

loopo5s

ldx #2665t

loopi5s

dbne x,loopi5s

dbne y,loopo5s

pulc

puly

pulx

rts

;--------------------------------------------------------------

; 1.5ms Delay

;--------------------------------------------------------------

delay1_5ms

pshx

pshy

pshc

ldy #1t

loopo1_5ms

ldx #1995t

loopi1_5ms

dbne x,loopi1_5ms

dbne y,loopo1_5ms

pulc

puly

pulx

rts

;--------------------------------------------------------------

; 20ms Delay

;--------------------------------------------------------------

delay20ms

pshx

pshy

pshc

ldy #2t

loopo20ms

ldx #26661t

loopi20ms

dbne x,loopi20ms

dbne y,loopo20ms

pulc

puly

pulx

rts

;--------------------------------------------------------------


F-26

; Turn Increment Delay

;--------------------------------------------------------------

delay_turn

pshx

pshc

loopi_inc

dbne y,loopi_inc

pulc

pulx

rts

;--------------------------------------------------------------

; 0.5ms Delay

;--------------------------------------------------------------

delay_5ms

pshx

pshy

pshc

ldy #1t

loopo_5ms

ldx #900t

loopi_5ms

dbne x,loopi_5ms

dbne y,loopo_5ms

pulc

puly

pulx

rts

;--------------------------------------------------------------

; 0.5ms Delay

;--------------------------------------------------------------

wait0_5ms

pshx

pshy

pshc

ldy #1t

loopo0_5ms

ldx #900t

loopi0_5ms

dbne x,loopi0_5ms

dbne y,loopo0_5ms

pulc

puly

pulx

rts

;--------------------------------------------------------------

; 4.5ms Delay

;--------------------------------------------------------------

wait4_5ms

psha

ldaa #7t

loop4_5ms

bsr wait0_5ms

dbne a, loop4_5ms

pula

rts

;--------------------------------------------------------------

; 15ms Delay

;--------------------------------------------------------------

wait15ms

psha

ldaa #4t

loop15ms


F-27

bsr wait4_5ms

dbne a, loop15ms

pula

rts

;**************************************************************

;* Interrupt Vectors *

;**************************************************************

ORG $FFFE

fdb Entry ; Reset


G-1

Appendix G: User Manual

GROVER Description

GROVER is the first robot ever to be used as an autonomous rogue agent in a paintball

arena. GROVER is designed to randomly patrol any sized area. This battery powered robot

travels on two rotating treads, similar to those of a tank, and includes a rotating turret that detects

heat-emitting targets by the use of PIR (Passive Infrared) sensors. The robot is capable of

obstacle avoidance using ultrasonic sensors and will travel in a straight obstacle free path until a

target is detected. Upon obstacle detection, the robot will halt, randomly face a new direction

and continue forward on its destruction path. Upon target detection, GROVER will stop and fire

an automatic weapon in the direction of the detected heat. An LCD screen will display the

number of engagements that GROVER has encountered during play. As a safety feature, the

referee of the game will be able to control a remote RF emergency shut-off switch. This can be

used after GROVER wipes out the entire floor of players and starts coming after the referees.

GROVER will provide a huge twist to the game of paintball and will keep everybody on the

move.


G-2

GROVER Illustration

GROVER was designed to be a very highly autonomous vehicle. Therefore, there are

few controls in the system. As seen in Figure G-1 below, a standard ON/OFF toggle switch is

located behind the gun. This can be used to keep GROVER out of trouble when game play is not

desired. There is also an RF remote shut-off switch that can be used in emergencies or to keep

GROVER stable while trying to find him. The RF receiver is connected to the power supply

system and will completely disable GROVER when the larger button is held down. The

ammunition magazine is located at the very top of GROVER and can hold approximately 100

rounds of ammo.

Figure G-1: GROVER


G-3

There is an LCD screen on the back end of GROVER for the display of the engagement

count. There are also 4 PIR sensors located on GROVER. One sensor is located on the front,

one is located on each side, and one narrow beam sensor is located just above the gun barrel.

The obstacle detection ultrasonic sensor is located on the front of GROVER as well. There are

also several batteries located on the robot. There is a 7.2V rechargeable RC battery located on

both sides of GROVER. There are also three 9V batteries located on the top tank deck for

powering the three lower PIR sensors. One 9V battery is also located in the turret for powering

the PIR sensor located in the gun. Each battery is easily accessible for changing or charging.


G-4

GROVER Setup

CAUTION: Failure to follow the instructions contained in this manual may result in injury to the user or to other persons. SAFETY GLASSES: Always wear safety glasses when operating GROVER. Step 1: Unpack GROVER Carefully remove all items from the box. Remove all packaging material. Step 2: Install the NiMH Batteries Insert one (1) 7.2V NiMH battery into each of the battery docking bays with the battery cables facing rearward. Once the batteries are secure, connect the battery cables to the battery receptacles at the rear of the robot. NOTE: Charge the batteries

for 14-16 hours before initial use.

Warning: Always check that GROVER’s power switch is in the downward position (OFF) before connecting the batteries.

Step 3: Install the 9V Batteries Connect 9V batteries to each of GROVER’s four (4) sensors.


G-5

Step 4: Load GROVER Load GROVER’s magazine with either 6mm plastic AirSoft pellets or 6mm paintballs. CAUTION:

Do not overfill magazine.


G-6

GROVER Use

Once you have followed the GROVER setup instructions on page 5, you are ready to go. Due to the autonomous nature of GROVER, the user-interface is simple to understand and very easy to use.

Interface 1: On/Off Switch To turn the device on, press the switch forward. To turn the device off, pull the switch back. NOTE:

Switch is shown in the off position in the picture at the right.

Interface 2: Remote Control To reset the device, press and release the top button (bigger button). To shut the device down, press and hold the top button (bigger button).


G-7

Interface 3a: LCD When the LCD reads “GROVER ARMED” this indicates that the device is activated and ready to fire after a sensor is triggered. CAUTION:

Proper safety procedures should be followed at this time.

Interface 3b: LCD When the LCD reads “RELOAD STNBY” this indicates that the device is out of ammo and needs to be filled in order to continue. CAUTION:

Although empty, caution should still be exercised to prevent injuries.

Interface 4: Reload Magazine As in step 4 or GROVER setup, load GROVER’s magazine with either 6mm plastic AirSoft pellets or 6mm paintballs. To resume action, reset GROVER as shown in Interface 2. CAUTION:

Do not overfill magazine. Overfilling may cause gun to jam.


G-8

Troubleshooting

The following section contains troubleshooting tips. If the problem persists, contact our customer service. See the Product Support Information section of this user manual for our customer service department contact information. GROVER does not turn on:

• Make sure the batteries are properly connected and fully charged.

• Make sure there is power to the main board by checking the two power indicator LEDs found in the mid section of GROVER. If they are off and the batteries are properly connected and charged, contact technical support.

• Make sure the remote RF switch button is not being held down. The LCD is not displaying anything:

• Make sure there is power to the main board by checking the two power indicator LEDs found in the mid section of GROVER. If they are off and the batteries are properly connected and charged, contact technical support.

• Make sure the LCD is properly and tightly connected to the main board. LCD contrast is too bright or too dark: Adjust the LCD contrast by adjusting the potentiometer in the main board using a small flat-head screwdriver. Make sure there is no power to the main board when you are doing this by setting the main power switch to “OFF”. LCD is displaying foreign or incorrect characters: There is some problem with the LCD or microcontroller. Contact technical support. This problem can only be serviced by a certified technician. LCD is not displaying the correct number of engagements: There is some problem with the microcontroller. Contact technical support. This problem can only be serviced by a certified technician. GROVER does not detect target:

• Make sure the batteries of the PIRs are properly connected and fully charged.

• The PIRs need a warm up period of about 2 minutes after the batteries are connected to properly detect targets.

GROVER does not align gun: There is some problem with the servo or microcontroller. Contact technical support. This problem can only be serviced by a certified technician.


G-9

GROVER does not align gun properly with the target:

• Make sure the battery of the gun PIR is properly connected and fully charged.

• The PIR needs a warm up period of about 2 minutes after the battery is connected to properly detect targets.

GROVER suddenly stops moving:

• Check the LCD and see if it is displaying “PWR: ON->RELOAD STNBY”. This means that GROVER is out of ammunition and needs to be reloaded. After the ammunition has been reloaded, reset GROVER.

• Make sure the remote RF switch button is not being held down.

• Make sure the batteries are properly connected and fully charged. GROVER does not move: There is some problem with the H-bridge or microcontroller. Contact technical support. This problem can only be serviced by a certified technician. GROVER does not turn or drive forward properly: Check the treads to make sure they are not loose. If they are, refit the treads. The RF remote does not disconnect power:

• Make sure you are in the RF remote’s range.

• Replace the RF remote’s battery.

• Make sure you are pressing the larger button on the remote. GROVER does not detect and avoid obstacles: There is some problem with the ultrasonic sensor or microcontroller. Contact technical support. This problem can only be serviced by a certified technician.


G-10

Product Support Information If you have read the operation manual and require further product support you can contact us using the information below.

GROVER Product Support Mail: GROVER Support Centre

465 Northwestern Ave. West Lafayette, IN 47907-2035 United States of America

URL: shay.ecn.purdue.edu/~477grp7 E-Mail: [email protected] Phone: 1-800-SHOOT-ME (1-800-746-6863) Fax: 1-765-743-0484

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bad

connec

tion

from

the

MC

U t

o

the

h-b

rid

ge

The

robot

wil

l not

move

in a

ce

rtai

n d

irec

tion

Obse

rvat

ion

Low

EC

E 4

77 F

inal

Rep

ort

Spri

ng 2

005

H

-3

C-4

R

obot

does

not

alig

n g

un

Soft

war

e fa

ilure

, dam

aged

MC

U,

dam

aged

ser

vo,

bad

connec

tion

from

the

MC

U t

o

the

serv

o

The

robot

wil

l not

alig

n g

un i

n

the

dir

ecti

on o

f th

e ta

rget

Obse

rvat

ion

Low

C-5

R

obot

does

not

fire

gun

Soft

war

e fa

ilure

, dam

aged

MC

U,

dam

aged

gun

inte

rfac

e ci

rcuit

, bad

connec

tion

from

the

MC

U t

o

the

gun i

nte

rfac

e ci

rcuit

The

robot

wil

l not

fire

the

gun

at t

he

targ

et

Obse

rvat

ion

Low

C-6

R

obot

does

not

dis

pla

y d

ata

on

the

LC

D

Soft

war

e fa

ilure

, dam

aged

MC

U,

dam

aged

LC

D

inte

rfac

e ci

rcuit

, bad

connec

tion

from

the

MC

U t

o

the

LC

D i

nte

rfac

e

The

robot

wil

l not

dis

pla

y d

ata

on t

he

LC

D

Obse

rvat

ion

Low

D-1

P

IR h

igh l

evel

in

put

to t

he

MC

U >

5 V

Volt

age

div

ider

dam

age

Per

man

ent

dam

age

to t

he

MC

U

Obse

rvat

ion

Hig

h

May

cau

se e

xce

ssiv

e hea

t dis

sipat

ion o

r ev

en f

ire

to t

he

com

ponen

ts

E-1

N

o d

ata

input

to

the

LC

D m

odule

S

oft

war

e fa

ilure

, dam

aged

MC

U,

dam

aged

74H

C164

shif

t re

gis

ter,

bad

co

nnec

tion

No d

ata

wil

l be

dis

pla

yed

on t

he

LC

D

Obse

rvat

ion

Low

EC

E 4

77 F

inal

Rep

ort

Spri

ng 2

005

H

-4

E-2

L

CD

pow

er =

0

V

Dam

aged

chip

pow

er s

upply

, bad

co

nnec

tion f

rom

th

e ch

ip p

ow

er

supply

No p

ow

er t

o t

he

LC

D

Obse

rvat

ion

Low

E-3

L

CD

pow

er >

5

V

Dam

aged

chip

pow

er s

upply

P

erm

anen

t dam

age

to t

he

LC

D m

odule

Obse

rvat

ion

Hig

h

May

cau

se e

xce

ssiv

e hea

t dis

sipat

ion o

r ev

en f

ire

to t

he

com

ponen

ts

F-1

M

oto

rs p

ow

er =

0 V

D

amag

ed c

hip

pow

er s

upply

, bad

co

nnec

tion f

rom

th

e m

oto

rs p

ow

er

supply

No p

ow

er t

o t

he

moto

rs

Obse

rvat

ion

Low

G-1

N

o s

ignal

to t

he

gun

Dam

age

to U

6, D

4,

Q1, S

oft

war

e fa

ilure

, dam

aged

M

CU

, bad

connec

tion

the

gun w

ill

not

fire

O

bse

rvat

ion

Low

G-2

G

un

conti

nuousl

y

firi

ng

Dam

age

to 4

N28,

Q1

The

gun w

ill

conti

nuousl

y f

ire

Obse

rvat

ion

Hig

h

Conti

nuous

unst

oppab

le s

hots

ca

n c

ause

bodil

y

inju

ry t

o t

he

use

r

Tab

le H

-1:

FM

EC

A W

ork

shee

t

Documents

ECE 477 Final Report Spring 2005 - College of …...ECE 477 Final Report Spring 2005 -iii- TABLE OF CONTENTS Abstract 1 1.0 Project Overview and Block Diagram 2 2.0 Team Success Criteria