Advanced Remote Monitoring and Operated Recon Device

Andrew LichensteinKevin Jadunandan

Thomas Kehr

Special Thanks

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Motivation

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Dragon Runner surveillance robot Extremely Durable Fast and lightweight platform ≈$32,000 per unit

Objectives: Fraction of the Price(< $2500) Maneuverability on all terrains Wireless Control/Video

iPhone Control

Hardware Block Diagram

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Specifications

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Physical

Length 18 in.

Width 14 in.

Height 10 in.

Weight 57 lb.

Power

Motor Battery 24V

Control Battery 12V

Communication

Video Frame Rate 30 fps

Operating Distance 100ft

LocomotionPeak Speed 6 mph

Wheel Size 10 in.

Motor RPM 252 rpm

Turn Radius 0°

Chassis

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Raw Material Selection

Suspension

Body Design

Component Mounting

Camera

Chassis: Raw Material Selection

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Aluminum Low-cost Light weight High cost of manipulation

Fiberglass Composite Extremely low cost Easily manipulated High Strength Experienced with fabrication Permeable to Radio frequencies

Fiberglass Carbon Fiber AluminumUltimate Strength (MPa) 3,450 5,650 40-50

Yield Strength (MPa) N/A N/A 15-20

Density (g/cm3) 2.57 1.75 2.7

Average Price ($/ft) 0.91 13.80 7.50

Carbon Fiber High cost High Strength Complex manipulation

Plastic Composite Extremely High Cost High StrengthLight WeightRequires Computer Generated Design

Chassis: Suspension

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Aluminum Frame – 1/8” Aluminum Sheet Provide mounting for components No metal on metal; rubber washers

Spring Suspension System 32 Springs 8 Motor Clamps

Chassis: Body Design

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Fiberglass-Composite Construction

Clam-Shell Design

Plug and Mold Fabrication

20”

7”

17”

Chassis: Component Mounting

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Camera Circuit Board and Motor Controller

Chassis: Polyurea

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Truck Bed Liner Rhino Liner, etc.

Extreme Durability 41 MPa Tensile Strength

Quick Reaction Time Build up Multiple Layers

Explosive and Ballistic resistance

Drive Train

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Geared Motor

Wheels and Locomotion

Drive Train: Motor Selection

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IG42 Geared Motor 24:1 Gear Ratio 24V DC 252 rpm 2300mA 10 kgf-cm Torque

4.8”

1.75”

Drive Train: Wheels and Locomotion

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Wheels Wheel + Tire 10” Diameter Custom Mounting Hardware

Wheel Speed Speed (fpm) = (Diameter of wheel (in) x π x rpm of

motor) /12 = (10” x π x 252) /12 = 659.7 ft/m = 7.59 mph

Power System

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Batteries

Charging Circuit

Control Battery

Drive Battery

Power System: Batteries

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NiMH Rechargeable Packs 24V 4500 mAHr

Drive Battery 12V 4000 mAHr

Control Battery

5" x 2" x 2"

10" x 2" x 2"

Power System: Charging Circuit

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DPDT Switch Toggles Between ON-OFF-Charge

Military Style Locking Connector

Power System: Control Battery

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Capacity = 4 AHr

Current Drain of system = 795mA

Estimated battery life ≈ 5 hrs

Component Current Draw

Operating Voltage

Power Consumption

XBee Pro 55ma 3.3V 0.18 Watts

Falcom FSA03 40ma 3.3V 0.132 Watts

PIC18F4520 200ma 5V 1 Watt

Wireless Camera

500ma 9V 4.5 Watts

Total 795ma 5.812 Watts

Power System: Drive Battery

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Battery Capacity= 4.5 AHr

Current Draw= 2300mA x 4 = 9.2 A

Battery Life = 29.3 minutes

Component Current Draw Operating Voltage

Power Consumption

IG42 Geared Motor 2300mA 24V 55.2Watts

Video System: Camera

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380-lines resolution

150-foot range (no obstacles)

900 MHz output frequency

Built-in microphone

Internal Hardware

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MCU

GPS

Communication

Motor Controller

Internal Hardware: MCU

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Features our group looked for in MCU: CPU Speed >= 4MIPS (10 MIPS)

Program Memory >= 16KB (32KB)

Internal Oscillator >= 4MHz (16MHz)

IO Pins >= 15 (30)

ADC >= 2 (15)

Program in C/C++ using MPLAB IDE

Temperature Range (-40 to 125 C)

PDIP

*PIC18F4520 Max Spec’s in ()

PIC18F4520

Internal Hardware: MCU

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Communication is the most essential part of our robot, we will need to be sending and receiving data from our Gateway to be able to control our robot. We will be using the hardware USART pins on the MCU, which allows us to send serial data reliably.

Our MCU will need to be data parse incoming GPS updates which come in the form of a string of characters. We will be emulating the hardware by emulating the hardware, using software USART.

Motor Control will be done by having two variables set , one for the left motors and one for the right motors. We will be sending a value of 0 to 255, which will tell which motor to move and how which direction it should spin the motor. This also will be using software USART.

Battery life and Temperature value will be done using AD Converters of the MCU, which takes voltage as inputs.

Communication: Options

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XBee vs. XBee Pro vs. Bluetooth Class 1

XBee XBee Pro Bluetooth Class 1

Indoor Range Up to 100ft

Up to 300ft

Up to 330 ft

Outdoor/LOS Up to 300ft

Up to 1 Mile

Up to 330 ft

Data Rate 250Kbps 250Kbps Up to 3 Mb/s

Unit Price $22.95 $37.95 $59.95

The Bluetooth was a bit to expensive and the regular XBee distance was a bit to small. This is why we chose the XBee Pro which was a good combination of both data rate and distance. We really only need 300 to 400 ft max for our application.

Internal Hardware: GPS

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We originally were looking at the Copernicus GPS Module that was sold on Sparkfun, but after talking with other sources they pointed out to me the Falcom FSA03 unit. Here are the details of the unit:

Copernicus FalcomCold Start 39 sec 29 sec

Hot Start 9 sec <1 sec

Antenna Not Included Attached

Update Rate 1Hz 4Hz

Channel 12 32

One of the best features of this chips is that it has a Sarantel helical antenna which lets you orient this GPS any way you would like , so you don’t have to make it point towards the sky.

Internal Hardware: Temperature Sensors

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The TMP35  outputs a voltage based off the current temperature around the sensor. Using the linear equation below, we can get the temperature on our microcontroller and motors.

Temp in °C = [(Vout in mV) - 500] / 10

Internal Hardware: Battery Life

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Using two simple voltage divider circuits to lower the voltage to a max of 5 volts, we check the battery voltage every other second. Knowing our fully charged voltage we can make an assumption on our remaining voltage as the voltage gets lower.

Communication: GPS Purpose

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The GPS’s main purpose was to be sending latitude and longitude to our microcontroller so that we could use this data with our iPhone application. The GPS sends NMEA(National Marine Electronics Association) data to our MCU; here is an example of what it looks like:

$GPGLL,4916.45,N,12311.12,W,225444,A,*1D

As you can see the data that is sent is not an easy to read format so our MCU will parse the data needed and send to a variable that will be sent out via XBee.

Geographic Lat & Lon

49o16.45

123o11.12

Time(UTC)

Data Active

Checksum

Motor Controller: Selection

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Originally we were thinking of creating our own motor controller using PNP BJTs but due to the fact we wanted stability and more features we decided to buy the Sabertooth 10A Dual Motor Controllers. One of the key features that we really liked as a group was that it is a regenerative motor driver, so when the robot stops or reverses it recharges the batteries with the wasted energy. It also has over current and thermal protection which means we won’t have to worry about damaging the motor controllers.

Motor Controller: Setup

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In our setup we will be using two motor controllers in parallel. So we will be using one pin on our MCU a Tx line that uses software USART that connects to the S1 ports on the motor controllers.

The Tx line on the MCU will transmit to both of the motor controllers S1 lines at the same time. We will be sending values of 0 to 255 to the motor controllers .

A value of 1 to 127 controls the left motors and a value of 128 to 255 controls the right motors

MCU Software Diagram

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RECEIVE THREAD SEND THREAD

DATA STRUCTURES

-Left Motor-Right Motor

-GPSLat-GPSLon

-BatteryLife

Board Design Prototype

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Created in EagleCAD

Screw Terminals make it easy to connect peripherals and stop wires from falling out

Custom PCB

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Using a flatbed plotter we make our own single sided PCBs for testing purposes. We can create 15 PCBs for less than $25.

Gateway / iPhone Interface

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Software applications

iPhone Application

Gateway Application

Last Minute Add-on: iPad App

Software Communication

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Software

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iPhone Application Primary controlling device

Touch based interface

Displays map with location of user and ARMORD

Software

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iPhone Application Written in Objective C

Apple’s object oriented version of C Runs all C code natively

Xcode IDE and Interface Builder Provides drag and drop UI design

Software: iPhone GUI

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Software: iPhone GUI

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Software: iPhone GUI

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Software: iPhone GUI

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Software: iPhone GUI

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Software: iPhone

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Software: iPhone

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Distance Calculation Uses latitude and longitude

Distance in miles = 3963.0 * arccos[sin(lat1) *  sin(lat2) +

cos(lat1) * cos(lat2) * cos(lon2 - lon1)]

Software: Gateway Application

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Purpose Wireless bridge between the iPhone and the ARMORD

Necessary because iPhone cannot easily connect to the XBee module

Communication Wi-Fi – iPhone XBee – Robot

Software: Gateway Application

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Requirements Wi-Fi connection COM port access

Options C# Java

Decision – C# Simple TCP Server and COM Port Access

Software: Gateway Application

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Software: Gateway Application

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iPad

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Control Scheme Turning - Accelerometer based

Forward/Reverse – Slider

“Steering Wheel”

iPad – Screenshot

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Software

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Packet Structure From iPhone To ARMORD

From ARMORD To iPhone

$ LEFT_MOTOR $ RIGHT_MOTOR

$ LATITUDE , LONGITUDE , MOTOR_BAT , MCU_BAT

TEMP ;

Video Transmission – Original Design

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Video is received by video capture card Computer broadcasts live stream over Wi-Fi iPhone plays live stream

Video Transmission – Original Design

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Problems For live video, iPhone only plays H264 video, with AAC

audio, encapsulated in an MPEG2-TS

Capture card software could not output proper video format

10 second video lag from camera to a computer watching the stream

Video Transmission – New Design

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Solution – External LCD Display Allows direct video feed from camera to display No processing on a computer to reduce video delay iPhone can now display more information on the

screenMapsGPS locationsDistanceBattery Life

Controller

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•Components 7” Standalone Monitor Ruggedized Grip and Frame AV Receiver 12V NiMH Battery

Video and Control up to 100 feet

Components attached to controller via aluminum bracket

Power supplied to AV Receiver and Monitor through 12V NiMH battery

Swivel mount to account for inversing camera orientation

Budget

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Part Name Quantity Price Total Cost

12V 2200mAHr NIMH 1 $23.90 $23.90 12V 4000mAHr NIMH 1 $53.60 $53.6024V 4500mAHr NIMH 2 $124.80 $249.60 Falcom FSA03 GPS 1 $59.95 $59.95 24V 252 RPM Geared Motor 5 $44.90 $224.50IPhone Grip 1 $25.50 $25.50 Sabertooth 10A Motor Controller 2 $79.99 $159.98 7 in. LCD 1 $79.99 $79.99 2.4GHz Mini Wireless Camera 2 $42.50 $85.00 900 MHz Mini Wireless Camera 1 $60.00 $60.00Truck Bed Liner 2 $9.95 $19.90 XBee Pro 3 $37.95 $113.85 XBee USB Explorer 2 $24.95 $49.90 XBee Breakout Board 1 $9.95 $9.95 PIC18F4520 3 $4.50 $13.50 Misc(Body, Copper Clad, Etc.) NA $400.00 $400.00

Developmental Tools NA $350.00 $350.00

Shipping/Handling NA $300.00 $300.00

Total $2429.14

Questions

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