Mini Documentation

8/8/2019 Mini Documentation

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1.1 Aim of the project:

The aim of the project is to design a robot which senses fire using fire

sensor .The robot is seamlessly operated utilizing a mobile handset. In order to

successfully execute a given task, control software is necessary that sends and

tracks appropriate orders to the robot. This project presents the design

principles of a general software framework capable to control any real time

robot without any set of feedback devices. A possible implementation of such

a general framework is provided together with experimental arrangement at a

minimal economy.

1.2 Hardware Requirements:

1. MICROCONTROLLER

2. HT9170B

3. ULN 2003

4. DPDT RELAYS

5. GARE MOTORS

6. MOBILE

7. FIRE SENSOR

1.3 Software Requirements:

TOOL: KEIL MICROVISION

LANGUAGE: EMBEDDED C

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1.4 Block Diagram:

Figure 1.1 Block diagram of Mobile Based Land Robot with Fire sensor.

2

DTMF

DECODE

R

HT9170B

GEAR

MOTOR2

GEAR

MOTOR1ULN2003

DRIVER

FIRE

SENSOR

POWER

SUPPLY

BUZZER

89S52


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1.5 Organization of the report:

The report totally consists of six chapters-

Chapter 1 gives the introduction,

Chapter 2 gives the details of hardware used,

Chapter 3 describes the realization of actual circuit,

Chapter 4 deals with the software development,

Chapter 5 gives the results and conclusions.

1.6 Conclusion:

Hence, this chapter gives a complete gist of the project details and the

technology implemented.

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2.1 Introduction:

In this chapter, all the hardware components that are used including the

microcontroller is explained elaborately. All the specifications and the internal

circuitry of the microcontroller including the functional features are explained

in detail so that the coding can be done accordingly.

2.2 Microcontroller-AT89S52:

The AT89S52 provides the following standard features: 8Kbytes of

Flash, 256 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, six-vectortwo-level interrupt architecture, a full duplex serial port, on-chip oscillator,

and clock circuitry. In addition, the AT89S52 is designed with static logic for

operation down to zero frequency and supports two software selectable power

saving modes. The Idle Mode stops the CPU while allowing the RAM,

timer/counters, serial port, and interrupt system to continue functioning. The

power down mode saves the RAM contents but freezes the oscillator,

disabling all other chip functions until the next hardware reset.

By combining a versatile 8-bit CPU with Flash on a monolithic chip,

the Atmel AT89S52 is a powerful microcomputer which provides a highly

flexible and cost effective solution to many embedded control applications.

2.2.1 Features of Microcontroller (8052):

Compatible with MCS-51 Products

8 Kbytes of In-System Re-programmable Flash Memory

Endurance: 1,000 Write/Erase Cycle

Fully Static Operation: 0 Hz to 24 MHz

Three-Level Program Memory Lock

256 x 8-Bit Internal RAM

32 Programmable I/O Lines

Three 16-Bit Timer/Counters

Eight vector two level Interrupt Sources

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Programmable Serial Channel

Low Power Idle and Power Down Modes

The Idle Mode stops the CPU while allowing the RAM,

timer/counters, serial port and interrupt system to continue functioning. ThePower Down Mode saves the RAM contents but freezes the oscillator

disabling all other chip functions until the next hardware reset.

2.2.2 Block Diagram of Microcontroller:

Figure 2.1 Block Diagram of 8052

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2.2.3 Pin Configuration:

Figure 2.2 Pin Diagram of 8052

2.2.4 Pin Description:

VCC

Pin 40 provides Supply voltage to the chip. The voltage source is +5v.

GND

Pin 20 is the grounded.

Port 0

Port 0 is an 8-bit open drain bidirectional I/O port from pin 32 to 39.

As an output port each pin can sink eight TTL inputs. When 1s are written to

port 0 pins, the pins can be used as high-impedance inputs. Port 0 may also be

configured to be the multiplexed low-order address/data bus during accesses to

external program and data memory. In this mode P0 has internal pull-ups.

Port 0 also receives the code bytes during Flash programming, and

outputs the code bytes during program verification. External pull-ups are

required during program verification.

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Port 1

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups from pin

1 to 8. The Port 1 output buffers can sink/source four TTL inputs. When 1s are

written to Port 1 pins they are pulled high by the internal pull-ups and can be

used as inputs. As inputs, Port 1 pins that are externally being pulled low will

source current (IIL) because of the internal pull-ups. Port 1 also receives the

low-order address bytes during Flash programming and 1program verification.

Port 2


21 to 28. The Port 2 output buffers can sink / source four TTL inputs. When 1s

are written to Port 2 pins they are pulled high by the internal pull-ups and can

be used as inputs. As inputs, Port 2 pins that are externally being pulled low

will source current (IIL) because of the internal pull-ups.

Port 2 emits the high-order address byte during fetches from external

program memory and during accesses to external data memory that uses 16-bit

addresses (MOVX @ DPTR). In this application it uses strong internal pull-

ups when emitting 1s. During accesses to external data memory that uses 8-bit

addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function

Register. Port 2 also receives the high-order address bits and some control

signals during Flash programming and verification.

Port 3


10 to 17. The Port 3 output buffers can sink / source four TTL inputs. When 1s

are written to Port 3 pins they are pulled high by the internal pull-ups and can

be used as inputs. As inputs, Port 3 pins that are externally being pulled low

will source current (IIL) because of the pull-ups.

Port 3 also serves the functions of various special features of the

AT89C51 as listed below:

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Table 2.1 Special Features of 89S52

Port 3 also receives some control signals for Flash programming and

programming verification.

RST

Pin 9 is the Reset input. It is active high. Upon applying a high pulse to

this pin, the microcontroller will reset and terminate all activities. A high on

this pin for two machine cycles while the oscillator is running resets the

device.

ALE/PROG

Address Latch is an output pin and is active high. Address Latch

Enable output pulse for latching the low byte of the address during accesses to

external memory. This pin is also the program pulse input (PROG) during

Flash programming. In normal operation ALE is emitted at a constant rate of

1/6 the oscillator frequency, and may be used for external timing or clocking

purposes.

If desired, ALE operation can be disabled by setting bit 0 of SFRlocation 8EH. With the bit set, ALE is active only during a MOVX or MOVC

instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable

bit has no effect if the microcontroller is in external execution mode.

PSEN

Program Store Enable is the read strobe to external program memory.

When the AT89S52 is executing code from external program memory, PSEN

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is activated twice each machine cycle, except that two PSEN activations are

skipped during each access to external data memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to

enable the device to fetch code from external program memory locations

starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is

programmed, EA will be internally latched on reset. EA should be strapped to

VCC for internal program executions. This pin also receives the 12-volt

programming enable voltage (VPP) during Flash programming, for parts that

require 12-volt VPP.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock

operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

2.2.5 Oscillator Characteristics:

XTAL1 and XTAL2 are the input and output, respectively, of an

inverting amplifier that can be configured for use as an on chip oscillator, as

shown in Figure 2.3. Either a quartz crystal or ceramic resonator may be used.

To drive the device from an external clock source, XTAL2 should be left

unconnected while XTAL1 is driven as shown in Figure 2.4.

Figure 2.3 Crystal Connections

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Figure 2.4 External Clock Drive Configuration

There are no requirements on the duty cycle of the external clock

signal, since the input to the internal clocking circuitry is through a divide-by

two flip-flop, but minimum and maximum voltage high and low time

specifications must be observed.

2.2.6 Programming Algorithm:

Before programming the AT89S52, the address, data and control

signals should be set up .To program the AT89S52, take the following steps.

1. Input the desired memory location on the address lines.

2. Input the appropriate data byte on the data lines.

3. Activate the correct combination of control signals.

4. Raise EA/VPP to 12 V for the high-voltage programming mode.

5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits.

The byte-write cycle is self-timed and typically takes no more than 1.5

ms. Repeat steps 1 through 5, changing the address and data for the entire

array or until the end of the object file is reached.

2.2.7 Data Polling:

The AT89S52 features Data Polling to indicate the end of a write

cycle. During a write cycle, an attempted read of the last byte written will

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result in the complement of the written data on PO.7. Once the write cycle has

been completed, true data are valid on all outputs, and the next cycle may

begin. Data Polling may begin any time after a write cycle has been initiated.

2.2.8Ready/Busy:

The progress of byte programming can also be monitored by the

RDY/BSY output signal. P3.4 is pulled low after ALE goes high during

programming to indicate BUSY. P3.4 is pulled high again when programming

is done to indicate READY.

2.2.9 Program Verify:

If lock bits LB1 and LB2 have not been programmed, the programmed

code data can be read back via the address and data lines for verification. The

lock bits cannot be verified directly. Verification of the lock bits is achieved

by observing that their features are enabled.

2.2.10 Chip Erase:

The entire Flash array is erased electrically by using the proper

combination of control signals and by holding ALE/PROG low for 10 ms. The

code array is written with all "1"s. The chip erase operation must be executed

before the code memory can be re-programmed.

2.2.11 Reading the Signature Bytes:

The signature bytes are read by the same procedure as a normal

verification of locations 030H, 031H, and 032H, except that P3.6 and P3.7

must be pulled to a

logic low. The values returned are as follows:

(030H) = 1EH indicates manufactured by Atmel

(031H) = 51H indicates 89C51

(032H) = FFH indicates 12 V programming

(032H) = 05H indicates 5 V programming.

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2.3 DTMF Receiver- HT9170B:

The HT9170B is a Dual Tone Multi Frequency (DTMF) receiver

integrated with digital decoder and band split filter functions as well as power-

down mode and inhibit mode operations. Such devices use digital counting

techniques to detect and decode all the 16 DTMF tone pairs into a 4-bit code

output.

Highly accurate switched capacitor filters are implemented to divide

tone signals into low and high group signals. A built-in dial tone rejection

circuit is provided to eliminate the need for pre-filtering.

2.3.1 Features:

Operating voltage: 2.5V~5.5V

Minimal external components

No external filter is required

Low standby current (on power down mode)

Excellent performance

Tristate data output for MCU interface

3.58MHz crystal or ceramic resonator

1633Hz can be inhibited by the INH pin

HT9170B:18-pinDIPpackage

2.3.2 Pin diagram:

Figure 2.6 DTMF Receiver

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Table 2.8 Pin Description

2.3.4 Block Diagram:

Figure 2.7 Block Diagram of Decoder IC

2.3.5 Functional Description:

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The HT9170B tone decoder consists of three band pass filters and two

digital decode circuits to convert a tone (DTMF) signal into digital code

output. An operational amplifier is built-in to adjust the input signal. The pre-

filter is a band rejection filter, which reduces the dialing tone from 350Hz to

400Hz. The low group filter filters low group frequency signal output whereas

the high group filter filters high group Frequency signal output. A zero-

crossing detector with follows each filters output hysteretic. When each signal

amplitude at the output exceeds the specified level, it is transferred to full

swing logic signal. When input signals are recognized to be effective, DV

becomes high, and the correct tone code (DTMF) digit is transferred.

Steering control circuit:

The steering control circuit is used for measuring the effective signal

duration and for protecting against drop out of valid signals. It employs the

analog delay by external RC time-constant controlled by EST. The EST pin is

normally low and draws the RT/GT pin to keep low through discharge of

external RC. When a valid tone input is detected, EST goes high to charge

RT/GT through RC.

When the voltage of RT/GT changes from 0 to VTRT (2.35V for 5V

supply), the input signal is effective, and the code detector will create the

correct code. After D0~D3 are completely latched, DV output becomes high.

When the voltage of RT/GT falls down from VDD to VTRT (i.e. when there is

no input tone), DV output becomes Low, and D0~D3 keeps data until a next

valid tone input is produced. By selecting adequate external RC value, theminimum acceptable input tone duration (TACC) and the minimum acceptable

inter-tone rejection (TIR) can be set. External Components (R, C) are chosen

by the formula.

TACC= TDP+TGTP;

TIR=TDA+TGTA;

Where,

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TACC: Tone duration acceptable time

TDP: EST output delay time (_L__H_)

TGTP: Tone present time

TIR: Inter-digit pause rejection time

TDA: EST output delay time (_H__L_)

TGTA: Tone absent time

2.3.7 Applications of Decoder:

Decoder can be used as,

PABX

Central office

Mobile radio

Remote control

Remote data entry

Call limiting

Telephone answering system

2.4 Relay Driver ULN 2003:

The ULN2803A is a high-voltage, high-current Darlington transistor

array. The device consists of eight NPN Darlington pairs that feature high-

voltage outputs with common-cathode clamp diodes for switching inductive

loads. The collector-current rating of each Darlington pair is 500 mA. The

Darlington pairs may be connected in parallel for higher current capability.

2.4.1 Features:

500-mA Rated Collector Current (Single Output)

High-Voltage Outputs . . . 50 V

Output Clamp Diodes

Inputs Compatible With Various Types of Logic

Relay Driver Applications

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Compatible with ULN2800A Series

2.4.2 IC Description:

Figure 2.9 Pin Diagram

Figure 2.10 Logic Diagram

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Figure 2.11 Schematic Diagram

2.4.3 Applications:

The applications include relay drivers, hammer drivers, lamp drivers,

display drivers (LED and gas discharge), line drivers, and logic buffers. The

ULN2803A has a 2.7-k series base resistor for each Darlington pair for

operation directly with TTL or 5-V CMOS devices.

2.5 Relays:

A relay is an electrically operated switch. Current flowing through the

coil of the relay creates a magnetic field which attracts a lever and changes the

switch contacts. The coil current can be on or off so relays have two switch

positions and they are double throw (changeover) switches.

2.5.1 DPDT Relay (DOUBLE POLE DOUBLE THROW):

Figure 2.13 Symbol of DPDT

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Figure 2.12 DPDT relay

2.5.2 Features of DPDT relays:

The features of the DPDT switches are as follows:

Can be used to isolate float switches from spiking voltage or

excessive current.

Avoids risk that spiking pump voltage will hurt float switches

Works with our 12 Volt Wall Transformer

Specifications:

o Coil voltage: 12VD

o Coil resistance: 160 Ohms

o Contact rating: 15A at 110VAC or 24VDC

2.5.2 SPST Relay (SINGLE POLE SINGLE THROW RELAY):

SPST Relays allow one circuit to switch a second circuit which can be

completely separate from the first. For example a low voltage battery circuit

can use a relay to switch a 230V AC mains circuit. There is no electrical

connection inside the relay between the two circuits; the link is magnetic and

mechanical.

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Figure 2.14 SPST relay

The relay's switch connections are usually labeled COM, NC and NO:

COM = Common, always connect to this, it is the moving part

of the switch.

NC = Normally Closed, COM is connected to this when the

relay coil is off.

NO = Normally Open, COM is connected to this when the

relay coil is on.

Connect to COM and NO if you want the switched circuit to be

on when the relay coil is on.

Connect to COM and NC if you want the switched circuit to be

on when the relay coil is off.

Figure 2.15 Circuit symbol of a relay

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The coil of a relay passes a relatively large current, typically 30mA for

a 12V relay, but it can be as much as 100mA for relays designed to operate

from lower voltages. Most ICs (chips) cannot provide this current and a

transistor is usually used to amplify the small IC current to the larger value

required for the relay coil.

Figure 2.16 Relay with Protection Diodes

2.5.3 Protection diodes for relays:

If the coil is energized with DC, a diode is frequently installed across

the coil, to dissipate the energy from the collapsing magnetic field at

deactivation, which would otherwise generate a spike of voltage and might

cause damage to circuit components

Relay coils produce brief high voltage 'spikes' when they are switched

off and this can destroy transistors and ICs in the circuit. To prevent damage

you must connect a protection diode across the relay coil.

Transistors and ICs (chips) must be protected from the brief high

voltage 'spike' produced when the relay coil is switched off. The diagram

shows how a signal diode (e.g. 1N4148) is connected across the relay coil to

provide this protection. Note that the diode is connected 'backwards' so that it

will normally not conduct. Conduction only occurs when the relay coil is

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switched off, at this moment current tries to continue flowing through the coil

and it is harmlessly diverted through the diode. Without the diode no current

could flow and the coil would produce a damaging high voltage 'spike' in its

attempt to keep the current flowing.

Relays and transistors compared:

Like relays, transistors can be used as an electrically operated switch.

For switching small DC currents (< 1A) at low voltage they are usually a

better choice than a relay. However transistors cannot switch AC or high

voltages (such as mains electricity) and they are not usually a good choice for

switching large currents (> 5A). In these cases a relay will be needed, but note

that a low power transistor may still be needed to switch the current for the

relay's coil! The main advantages and disadvantages of relays are listed below:

2.5.4 Advantages of relays:

Relays can switch AC and DC, transistors can only switch DC.

Relays can switch high voltages, transistors cannot.

Relays are a better choice for switching large currents (> 5A).

Relays can switch many contacts at once.

2.5.5 Disadvantages of relays:

Relays are bulkier than transistors for switching small currents.

Relays cannot switch rapidly (except reed relays), transistors

can switch many times per second.

Relays use more power due to the current flowing through their

coil.

Relays require more current than many chips can provide, so a low

power transistor may be needed to switch the current for the relay's coil.

2.6 Motors Helical Gear Motors:

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A unit which creates mechanical energy from electrical energy and which

transmits mechanical energy through the gearbox at a reduced speed is a Gear

motor.

A gear head and motor combination is to reduce the speed of the motor to

obtain the desired speed or torque.

Figure 2.17 Helical Gear Motor

Gear motors of all types and sizes include single / multiphase,

universal, servo, induction and synchronous types. DC gear motors are

configured in many types and sizes, including brushless and servo. A DC gear

motor consists of a rotor and a permanent magnetic field stator and an integral

gearbox or gear head. The magnetic field is maintained using either permanent

magnets or electromagnetic windings. DC motors are most commonly used in

variable speed and torque applications. A DC servomotor has an output shaft

that can be positioned by sending a coded signal to the motor. As the input to

the motor changes, the angular position of the output shaft changes as well.

Servomotors are generally small and powerful for their size, and easy to

control. Common types of DC servomotors include brushless or gear motor

types.

2.7 Fire Sensor:

In Fire sensor we have six pins. Three pins are shorted and

connected to vcc. On the other side middle pin is connected to ground and the

remaining two pins are shorted and connected to base of the transistor.

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Initially when sensor is not detecting smoke we have less than 0.7v at the base

of the transistor. If the base voltage is less than 0.7 then the transistor won t

conduct and the output at the collector is logic 1 i.e. +5v. When the sensor

detects smoke than the voltage at the transistor will be high and the transistor

starts conducting and voltage at the collector is logic 0. We will be connecting

the collector output to a buzzer by using one diode. This buzzer will be

ringing when it receives logic 0 i.e. when the sensor detects smoke. In the

transmitting side, the output of smoke sensor is connected to the

microcontroller P3.1 (second pin). Whenever there is no smoke this pin will

read logic 0 initially. When it detects smoke the pin will read logic 1. Then

microcontroller will send the data to the encoder by using port 1 first four

pins. To pin P1.0 we will send logic 1 and the remaining pins will be zero.

This data is send by the microcontroller to the encoder IC, which in turn

encodes the data. The encoded data is transmitted to the transmitter third pin.

From there it will transmit the data with a frequency of 433MHz.In receiving

side, the receiver receives the data and decodes the data by the decoder and

sends that data to the microcontroller. When ever the receiving side

microcontroller receives logic 1 at P1.0 it will make the buzzer on.

Fig: 2.18 Fire sensor

2.8 Conclusion:

The hardware components used with the microcontroller has been

clearly explained. The other hardware like the motors and their driving circuits

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are explained. The relays and the IC of DTMF technology have been

introduced in this chapter.

3.1 Introduction:

In this chapter, the entire circuitry of the project is shown. The design

parameters kept in mind while the circuits are being designed are clearly

explained. Also the chapter includes the main important part of any hardware

project i.e., a power supply, its circuit and its internal circuit components. On

the whole this chapter gives the circuits employed in the whole projects and

their interfacing.

3.2 Power supply:

There are many types of power supply. Most are designed to converthigh voltage AC mains electricity to a suitable low voltage supply for

electronics circuits and other devices. A power supply can by broken down

into a series of blocks, each of which performs a particular function. For

example a 5V regulated supply can be shown as below

Fig 3.1: Block Diagram of a Regulated Power Supply System

Similarly, 12v regulated supply can also be produced by suitable

selection of the individual elements. Each of the blocks is described in detail

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below and the power supplies made from these blocks are described below

with a circuit diagram and a graph of their output:

3.2.1 Transformer:

A transformer steps down high voltage AC mains to low voltage AC.

Here we are using a center-tap transformer whose output will be sinusoidal

with 36volts peak to peak value.

Fig: 3.2 Output Waveform of transformer

The low voltage AC output is suitable for lamps, heaters and special

AC motors. It is not suitable for electronic circuits unless they include a

rectifier and a smoothing capacitor. The transformer output is given to the

rectifier circuit.

3.2.2 Rectifier:

A rectifier converts AC to DC, but the DC output is varying. There are

several types of rectifiers; here we use a bridge rectifier.

The Bridge rectifier is a circuit, which converts an ac voltage to dc

voltage using both half cycles of the input ac voltage. The Bridge rectifier

circuit is shown in the figure. The circuit has four diodes connected to form a

bridge. The ac input voltage is applied to the diagonally opposite ends of the

bridge. The load resistance is connected between the other two ends of the

bridge.

For the positive half cycle of the input ac voltage, diodes D1 and D3

conduct, whereas diodes D2 and D4 remain in the OFF state. The conducting

diodes will be in series with the load resistance RL and hence the load current

flows through RL.

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For the negative half cycle of the input ac voltage, diodes D2 and D4

conduct whereas, D1 and D3 remain OFF. The conducting diodes D2 and D4

will be in series with the load resistance RL and hence the current flows

through RL in the same direction as in the previous half cycle. Thus a bi-

directional wave is converted into unidirectional.

Figure 3.3 Rectifier circuit

Now the output of the rectifier shown in Figure 3.3 is shown below in Figure

3.4

Figure 3.4 Output of the Rectifier

The varying DC output is suitable for lamps, heaters and standard

motors. It is not suitable for lamps, heaters and standard motors. It is not

suitable for electronic circuits unless they include a smoothing capacitor.

Smoothing:

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The smoothing block smoothes the DC from varying greatly to a

small ripple and the ripple voltage is defined as the deviation of the load

voltage from its DC value. Smoothing is also named as filtering.

Filtering is frequently effected by shunting the load with a capacitor. The

action of this system depends on the fact that the capacitor stores energy

during the conduction period and delivers this energy to the loads during the

no conducting period. In this way, the time during which the current passes

through the load is prolonging Ted, and the ripple is considerably decreased.

The action of the capacitor is shown with the help of waveform.

Figure 3.5 Smoothing action of capacitor

Figure 3.6 Waveform of the rectified output smoothing

3.2.3 Regulator:

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Regulator eliminates ripple by setting DC output to a fixed voltage.

Voltage regulator ICs are available with fixed (typically 5V, 12V and 15V) or

variable output voltages. Negative voltage regulators are also available

Many of the fixed voltage regulator ICs has 3 leads (input, output and high

impedance). They include a hole for attaching a heat sink if necessary. Zener

diode is an example of fixed regulator which is shown here.

Figure 3.7 Regulator

Transformer + Rectifier + Smoothing + Regulator:

Figure 3.8 Circuit for Regulated DC output

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3.3 Complete Circuit diagram employed:

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Figure 3.9 Complete Circuit Diagram Used.

3.3.1Circuit Description:

The main aim of the project is development of robot control using

mobile phone. Here we used DTMF IC to decode tones that are received from

the dialed phone into hex values (i.e. if you press 1 from the dialed phone the

receiver phone receives the tone and transfer to the DTMF IC HT 9170 B as

this IC converts into hex equivalent i.e. 0x01) which are parallels transferred

to the microcontroller port 1 lower bits.

In controller section we write an software program for two motors

defined below to move in different directions according to the values received

from the DTMF IC

We use two helical gear motors to rotate the two rear wheels, one for

each. These motors rotate the entire equipment in 4 directions: left, right,

forward and backward directions. We use 2,4,6and 8 from the dialed telephone

key pads for respective direction as the controller receives 0x02,0x04,0x06

and 0x08 from DTMF IC.

3.4 Project Implementation using DTMF Technology:

As the motors will on and off with help of the relays connected to the

different motors. As we know that relay acts as the switch to on/off the motor.

Relays DPDT used here to rotate helical gear motor in clock-wise as

well as anti-clock wise.

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All the relays used here operate for the 12v dc which microntroller

cannot be used to drive them. Hence we use driver IC ULN2003s to

drive the relays to on the appropriate motors.

The controller operates for 5v dc and driver IC operates for 12v dc.

3.5 Working description:

In our project, we have employed +5v and +12 v dc voltages. These dc

voltages have been obtained from the regular 230v ac power supply, the ac

signal has to be passed through the step down transformer, rectifier, filter and

regulators. In order to convert into dc we incorporated a bridge rectifier as its

efficiency is very high (approximately 100%) compared to other rectifier

circuit. A 12-0-12 step-down transformer decreases the voltage level of ac

signal from 230 V to 12V (ac).The filter eliminates the ripples and 78X series

regulators gives the constant dc.

The DTMF signal generated by the operators mobile, is transfered to the

decoders input through the head set. The corresponding signal which is

received will be decoded by HT9170B decoder and decoded output bits DB3,

DB2 , DB1, DB0 are given to the ports pin of the

microcontroller.DB3,DB2,DB1,DB0 are given to the P2.3,P2.2,P2.1,P2.0

respectively.

Corresponding to the input bits given to the controller, the controller generates

the bits according to the code program we have given and these bits are givento the driver IC. The driver IC output is given to both the relays and hence

controlling the motor action. Depending on the motors rotation (either clock or

counter clock) the land robot moves in the all four directions.

The smoke sensor senses the smoke and the output of the sensor circuit is

given to the P0.0 pin of controller. Then the buzzer which is connected to the

P0.7gets on and it gives the buzzer sound indicating the smoke.

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3.6 Conclusion:

This chapter has included the main important part of any hardware

project i.e., a power supply, its circuit and its internal circuit components. On

the whole this chapter has given the circuits employed in the whole projects

and their interfacing

4.1 Introduction:

This chapter gives the advantages and disadvantages of the project.

The various applications in which the project can be utilized and implementedare furnished in the chapter. Finally, the chapter is ended with the conclusion.

4.2 Advantages of Robot:

Quality:

Robots have the capacity to dramatically improve product quality.

Applications are performed with precision and high repeatability every

time. This level of consistency can be hard to achieve any other way.

Production:

With robots, throughput speeds increase, which directly impacts

production. Because robots have the ability to work at a constant speed

without pausing for breaks, sleep, vacations, they have the potential to

produce more than a human worker.

Safety:

Robots increase workplace safety. Workers are moved to supervisory

roles, so they no longer have to perform dangerous applications in

hazardous settings.

Savings:

Greater worker safety leads to financial savings. There are fewer

healthcare and insurance concerns for employers.Robot also offer

untiring performance which saves valuable time. Their movements are

always exact, so less material is wasted.

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4.3 Disadvantages of Robot:

Network:

As our robot is operated through mobile, sometimes network jam can

be a problem

Expense:

The initial investment of robots is significant, especially when business

owners are limiting their purchases to new robotic equipment. The cost

of automation should be calculated in light of a business' greater

financial budget. Regular maintenance needs can have a financial toll

as well.

Expertise:Employees will require training in programming and interacting with

the new robotic equipment. This normally takestime and financial

output.

4.4 Applications:

The applications of the Robot can broadly be classified in two

categories.

Fire Mishaps:

In the event of a fire accident it is better to send the robot, than to send

a human inside the affected area to, either search and rescue a person

or for surveillance purposes. The arm can also be equipped with a fire

extinguisher to put off the fire.

Bomb Detection:In the likely event of a bomb alert, this robotic arm can safely go,

detect and diffuse the bomb instead of a human being risking his life.

In Space Explorations as Land Rover:

Recent Chandryaan moon mission employs such robotic arms (a

complete version of the robot), to survey the geographical and

chemical composition of the surface of the Moon. NASA also has used

such robots in its survey of Mars. The collected samples from the

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surface are then transported back to the space shuttle, from where other

chemical tests are conducted, and results relayed back to Earth.

In Coal Mines:

In coal mines it is quite natural that Methane gas leaks occurs. Therobot can be equipped with a Methane gas sensor and warn the

presence of said gas, without exposing humans to the danger.

4.5 Conclusion:

The advantages and disadvantages explained earlier in this chapter

justify the significance of a mobile based robotic arm. The application areas

are also vast with the simplest of modifications. Since all we need is a mobile

call establishment to instruct the robot due to the cell phones unending and

cheap availability, this is highly feasible. The signals received at the robots

mobile is decoded with DTMF decoder which is easy to use. No heavy motors

are employed in the making of the robot, and thus it becomes very light

weight. The level of sophistication is quite low and hence its working is user

friendly.

Since this robot is highly flexible adding components to facilitate

application specific working yields a robot that has high use in vast areas. This

project can also be subjected to standardization and hence has a good future

scope.

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REFERENCES:

1. "The 8051 Microcontroller Architecture, Programming & Applications"by Kenneth J Ayala.

2. "The 8051 Microcontroller & Embedded Systems" by Mohammed Ali

Mazidi and Janice Gillispie Mazidi

3. "Power Electronics" by M D Singh and K B Khanchandan

4. "Linear Integrated Circuits" by D Roy Choudary & Shail Jain

5. "Electrical Machines" by S K Bhattacharya

6. "Electrical Machines II" by B L Thereja

7. www.8051freeprojectsinfo.com

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APPENDIX

SOURCE CODE:

#include

delay(unsigned char);sbit L_MOTORFORWARD=P1^0;

sbit L_MOTORBACKWARD=P1^1;

sbit R_MOTORFORWARD=P1^7;

sbit R_MOTORBACKWARD=P1^6;

sbit smoke =P0^0;

sbit buzzer=P0^7;

Void main()

{

L_MOTORFORWARD=0;

L_MOTORBACKWARD=0;

R_MOTORFORWARD=0;

R_MOTORBACKWARD=0;

buzzer=0;

while (1)

{

if(smoke==1)

{

buzzer=1;

delay(10);

}

else

{

buzzer=0;

}

//FORWARD

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if(P2==0xF2)

{

L_MOTORFORWARD=1;

R_MOTORFORWARD=1;

delay(250);

L_MOTORFORWARD=0;

R_MOTORFORWARD=0;

}

//LEFT

if(P2==0xF4)

{

L_MOTORFORWARD=1;

delay(250);

L_MOTORBACKWARD=0;

R_MOTORFORWARD=0;

R_MOTORBACKWARD=0;

}

//RIGHT

if(P2==0xF6)

{

R_MOTORFORWARD=1;

delay(250);

L_MOTORFORWARD=0;

L_MOTORBACKWARD=0;

R_MOTORBACKWARD=0;

}

//BACK

if(P2==0xF8)

{

L_MOTORBACKWARD=1;

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R_MOTORBACKWARD=1;

delay (250);

L_MOTORBACKWARD=0;

R_MOTORBACKWARD=0;

}

} //while

} //main

//DELAY

delay(unsigned char time)

{

unsigned char i,j;

for(i=0;i

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