main report rf robot

8/16/2019 Main Report Rf Robot

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The circuit of this project uses RF module to control DC motors through a motor

driver IC L293D. Transmission is enaled ! giving a lo" it to pin#$ %T&' active lo"(

of encoder )T#2&. The controls for motor are *rst sent to )T#2&. +ins #, and ##

%D,-D#( are used to control one motor "hile pins #2 and #3 %D2-D3( to control

another motor. The data signals of encoder )T#2& "or on negative logic. Therefore

a particular signal is sent ! giving a lo" it to the corresponding data pin ofencoder.

The parallel signals generated at transmission end are *rst encoded %into serial

format( ! )T#2& and then transferred through RF transmitter %$3$ /)0( at a aud

rate of around #-#, ps. The same signals are ac1uired ! RF receiver after "hich

it is decoded ! )T#2D. For more details' refer RF remote control.

ince the encoderdecoder pair used here "ors on negative logic' the decoded

signals are fed to an inverter %45T gate( IC 6$L,$. The proper %inverted( signals

are then supplied to L293D. L293D contains t"o inuilt )-ridge driver circuits to

drive t"o DC motors simultaneousl!' oth in for"ard and reverse direction.

The motor operations of t"o motors can e controlled ! input logic at pins 2 7 6

and pins #, 7 #8. Input logic ,, or ## "ill stop the corresponding motor. Logic ,#

and #, "ill rotate it in cloc"ise and anticloc"ise directions' respectivel!. Thus'

depending upon the signals generated at the transmission end' the t"o motors can

e rotated in desired directions.

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COMPONENTS:-

RF Module (Transmitter & Receiver)

The RF module, as the name suggests, operates at Radio Frequency. The corresponding

frequency range varies between 30 k! " 300 #!. $n this RF system, the digital data is

represented as variations in the amplitude of carrier wave. This kind of modulation is known as

%mplitude &hift 'eying (%&').

Transmission through RF is better than $R (infrared) because of many reasons. Firstly, signals

through RF can travel through larger distances making it suitable for long range applications.

%lso, while $R mostly operates in line*of*sight mode, RF signals can travel even when there is an

obstruction between transmitter " receiver. +et, RF transmission is more strong and reliable

than $R transmission. RF communication uses a specific frequency unlike $R signals which are

affected by other $R emitting sources.

This RF module comprises of an RF Transmitter and an RF Receiver. The

transmitter-receiver (T-R) pair operates at a frequency of 44 M!". %n RF transmitter

receives serial data and transmits it wirelessly through RF through its antenna connected at pin.

The transmission occurs at the rate of /'bps * /0'bps.The transmitted data is received by an RF

receiver operating at the same frequency as that of the transmitter. The RF module is often used

alongwith a pair of encoder-decoder. The encoder is used for encoding parallel data for

transmission feed while reception is decoded by a decoder. T/1*T/2, T0*T4, etc.

are some commonly used encoder-decoder pair $5s.

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Pin dia#ram :-

Pin $escri%tion:

RF Transmitter

Pin No Function Name

/ #round (06) #round

&erial data input pin 2ata

3 &upply voltage7 86 6cc

%ntenna output pin %+T

RF Receiver

Pin No Function Name

/ #round (06) #round &erial data output pin 2ata

3 9inear output pin7 not connected +5

&upply voltage7 86 6cc

8 &upply voltage7 86 6cc

#round (06) #round

: #round (06) #round


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4 %ntenna input pin %+T

'$:-

9;32 is a dual *bridge motor driver integrated circuit ($5).


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PN $*+R*M:-


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Pin $escri%tion:-

>in +o Function +ame

/ 1nable pin for


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!,R$+E CRC.T:-

This pro@ect and circuit finds a huge application in the area of robotics to control motor direction.

This circuit uses the basic concept of transistors as a switch. Transistor with proper biasing can

be used as switch, i.e. it can be used to toggle between the two states of a switch on or off. Thisconfiguration of transistor has been used in *bridge to drive a motor in both clockwise and

anticlockwise direction. This circuit derives its name from the 1nglish alphabet AB, which

closely resembles the circuit pictorially

The description of the circuit based pro@ect can be divided into two parts. The first part eplains

the concepts behind the working transistor as switch and the second part the function and

operation of Cridge.

$ESCRPTON OF ! R$+E CRC.T:-

/. Transistor as switchD*

The circuit diagram in the figure / shows the use application of transistor as a switch. =hen

there is no input on the base, the transistor is in the cut off region and acts as an open switch. %s

a result the 912 does not glow. =hen the base is given an input through a resistance

R/, the transistor gets biased and enters into saturation state, hence behaving like a closed

switch. %s a result the current starts flowing through the 912 and it starts glowing.. *bridgeD*

$n *bridge four npn transistors (C58:) are used in the switch mode configuration. The

emitter and collector of transistors T/ " T and of T3 " T are connected. The collector of T/"

T3 is connected to 655 and emitter of T" T is connected to ground. The base of T/ " T and

T " T3are connected through resistors. The motor is connected as shown in the figure. =hen

high signal (logic /) is given at % and low (logic 0) at C, the transistor T/ " T will behave as

closed switch andT " T3 will behave as open switch. %s a result of which the current will start

flowing from 6cc to T/ to motor to T to ground and motor will start running in one direction.

&imilarly if C is given high signal and % low, then the transistors T/" T are in the cut off state

and T and T3 are in the saturation state i.e., T/ " Tbehave as open switch and T " T3behave

as closed switch and motor rotates in other direction. =e should avoid giving either high or low

to both % " C simultaneously.

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CRC.T $*+R*M

2iagram / diagram


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Transistor C/40

C/40 is an +>+ bi*polar @unction transistor. % transistor, stands for transfer of resistance, is

commonly used to amplify current. % small current at its base controls a larger current at

collector " emitter terminals.

C/40 is mainly used for amplification and switching purposes. $t has a maimum current gain

of 400. $ts equivalent transistors are C584 and C58;.

The transistor terminals require a fied 25 voltage to operate in the desired region of its

characteristic curves. This is known as the biasing. For amplification applications, the transistor

is biased such that it is partly on for all input conditions. The input signal at base is amplified and

taken at the emitter. C58: is used in common emitter configuration for amplifiers. The voltage

divider is the commonly used biasing mode. For switching applications, transistor is biased sothat it remains fully on if there is a signal at its base. $n the absence of base signal, it gets

completely off.


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Pin $ia#ram:


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Resistor:-

Resistor is a passive component used to control current in a circuit. $ts resistance is given by the

ratio of voltage applied across its terminals to the current passing through it. Thus a particular

value of resistor, for fied voltage, limits the current through it. They are omnipresent inelectronic circuits.

The different value of resistances are used to limit the currents or get the desired voltage drop

according to the current*voltage rating of the device to be connected in the circuit. For eample,if an 912 of rating .36 and m% is to be connected with a supply of 86, a voltage drop of .:6

(86*.36) and limiting current of m% is required. This can be achieved by providing a resistor

of 80 connected in series with the 912.

Resistors can be either fied or variable. The low power resistors are comparatively smaller in

si!e than high power resistors. The resistance of a resistor can be estimated by their colour codes

or can be measured by a multimeter. There are some non linear resistors also whose resistance

changes with temperature or light. +egative temperature coefficient (+T5), positive temperature

coefficient (>T5) and light dependent resistor (92R ) are some such resistors. These special

resistors are commonly used as sensors. Read and learn about internal structure and working of

a resistor .

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Transistor 'N'''':-

'N'''' is an NPN 1T transistor. $t is used for general purpose low*power amplification and

switching applications. These are designed for high speed switching application at collector

current up to 400m%. $t provides useful current gain over a wide range of collector current. ?ther

features include, low leakage currents and low saturation voltage. 'N''''* is another variant

with improved characteristics.

The emitter leg of 'N'''' is indicated by a protruding edge in the transistor case. The base is

nearest to the emitter while collector lies at other etreme of the casing.


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S.MM*R2D*

=ireless remote controlled toy cars work on the concept eplained in this pro@ect.


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C 04S34:-

0434 is a +OT #ate C. $t consists of si inverters which perform logical invert action. The

output of an inverter is the complement of its input logic state, i.e., when input is high its output

is low and vice versa.

Pin $ia#ram:


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Pin $escri%tion:

Pin No Function

/$nput-output of /st inverter

3$nput-output of nd inverter

8$nput-output of 3rd inverter

: #round (06)

4?utput-input of th inverter

;

/0?utput-input of 8th inverter

//

/?utput-input of th inverter

/3

/ &upply voltage7 86 (.:8 * 8.8 6


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!T'E Encoder C

!T'E is an encoder inte#rated circuit of / series of encoders. They are paired with / series

of decoders for use in remote control system applications. $t is mainly used in interfacing RF and

infrared circuits. The chosen pair of encoder-decoder should have same number of addresses and

data format.

&imply put, T/1 converts the parallel inputs into serial output. $t encodes the / bit parallel

data into serial for transmission through an RF transmitter. These / bits are divided into 4address bits and data bits.

T/1 has a transmission enable pin which is active low. =hen a trigger signal is received on

T1 pin, the programmed addresses-data are transmitted together with the header bits via an RF or

an infrared transmission medium. T/1 begins a *word transmission cycle upon receipt of a

transmission enable. This cycle is repeated as long as T1 is kept low. %s soon as T1 returns to

high, the encoder output completes its final cycle and then stops.


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Pin $ia#ram:


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loc5 $ia#ram


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Pin $escri%tion:

Pin No Function

/

4 bit %ddress pins for input

3

8

:

4

; #round (06)

/0

bit 2ata-%ddress pins for input//

/

/3

/ Transmission enable7 active low

/8 ?scillator input

/ ?scillator output

/: &erial data output

/4 &upply voltage7 86 (.6*/6)

!T'$ $ecoder C


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!T'$ is a decoder inte#rated circuit that belongs to / series of decoders. This series of

decoders are mainly used for remote control system applications, like burglar alarm, car door

controller, security system etc. $t is mainly provided to interface RF and infrared circuits. They

are paired with / series of encoders. The chosen pair of encoder-decoder should have same

number of addresses and data format.

$n simple terms, T/2 converts the serial input into parallel outputs. $t decodes the serial

addresses and data received by, say, an RF receiver, into parallel data and sends them to output

data pins. The serial input data is compared with the local addresses three times continuously.

The input data code is decoded when no error or unmatched codes are found. % valid

transmission in indicated by a high signal at 6T pin.

T/2 is capable of decoding / bits, of which 4 are address bits and are data bits. The data

on bit latch type output pins remain unchanged until new is received.

Pin $ia#ram:


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Pin $escri%tion:


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Pin No Function

/

4 bit %ddress pins for input

3

8

:

4

; #round (06)

/0

bit 2ata-%ddress pins for outpu//

/

/3

/ &erial data input

/8 ?scillator output

/ ?scillator input

/: 6alid transmission7 active high

/4 &upply voltage7 86 (.6*/6)

loc5 dia#ram:-


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main report rf robot

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