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Data Communication Using Power Line

 

 

 

 

Objective:-

 

PLCC

Voice Communication using Powerline

 

 

 

Introduction:

Theory of circuit

Power line is used to transfer electric energy from electric generator to our daily electric equipments. Every building has power line, including our house does. If a building need electric energy, it should get connected to electric supplier (maintain by the state). We can figure it out that all of buildings are connected through this power line. So, we can say that we've already have a "network" before internet was launched.

The main function of power line is distributing electric energy. We can inject a new signal to power line, with our own need. FCC rule said that a range of frequency between 65kHz-75kHz at power line can be used to send data or signal. Here is enclosed our circuit which send audio signal encoded in FM mode through power line and a receiver to decode it from.

Electric power that run at power line has a shape of sinusoidol, in electrical ways it contain amplitude and frequency. First, injected signal may not annoying main signal, so we must send as small as possible on. But remember, there are always noises at the line. The point is, we must send a small signal but large enough compared to the noises. The second, use range permitted, that cause a modulation involved. In this case we use frequency modulation method with 70kHz as the carrier frequency.

Construction

Each component can be constructed at two PCB. One as the transmitter and the other as receiver. We can build more than one receiver. Tune potentiometer T1 at both transmitter and receiver to get the same frequency . We need oscilloscope to get the exact one. Then trim IF transformer to get best sinusoidal carrier. we use  IF transformer it frequency has shifted about 70kHz by capasitor parallel at.

Potentiometer T2 to set the amount of carrier level injected at power line. We can set it up by hearing the best sound quality. Just put an audio source at the transmitter and an earphone at the receiver.

IN this circuit we use two  circuit one is dtmf generator and second is operational amplifier. In the dtmf generator circuit we use ic um 91214 as a dtmf generator. Working voltage of this ic is 3.3 volt dc. So that we use one 3.3 volt zener diode as a regulator and provide a regulated power supply to this circuit. Output signal is available on the pin no 7 . this output signal is coupled to the input of the amplifier through selector switch. One 3.58 mhtz crystal is connected to the pin no 3 and 4 to give a carrier frequency to the circuit. IN this mode we use 3.58 mhtz crystal  as a main carrier source of the dtmf generator.

 

All the switches are connected to the input of the dtmf generator to provide a multiple signals. All the switches are connected in four rows and three coloum. When we press any key then one row and one coloum is activate automatically.

 

Data from the dtmgf generator is further connected to the pin no 2 of the ic 741 through capacitor .04 micro farad. Here capacitor block the dc voltage and pass only signal to the amplifier circuit. Pin no 6 is the output pin no of the ic 741. Pin no 3 is connected to zero voltage through voltage divider circuit. Here we use two 10 k ohm resistor as a voltage divider components. Two 10 k ohm resistor provide a zero reference voltage to the pin no 3 of the ic 741. Output of the ic 741 is further amplify by the two transistor circuit. Here we use one is npn and second is pnp transistor . Collector of the npn transistor is connected to the positive voltage and collector of the pnp transistor is connected to the negative voltage. Output of the transistor is available on the emitter point and this output voltage is connected to the laser diode through one current limiting resistor and one zener diode.

 

Analogue signal from condenser mike is also feeded to the input of the op-amplifier using selector switch. Condenser mike convert the sound signal into electrical singal and this signal is  coupled to the pin no 2 of the ic 741 through .04 microfarad capacitor. Resistor 10 k ohm provide a dc voltage to the condenser mike.

 

Gain of the amplifier or ap-amp is depend on the feedback connec mmmmted to the circuit. In this project we use one 10 k ohm resistor in series with the  100 k ohm variable resistor. With the help of this variable resistor we control the gain of the op-amplifier.

 

Now whatever we speak or  press the switch this data is  superimposed on the light of the laser. Laser respond this signal and then this signal is focus on the photodiode  in the line of sight.

 

 

In the receiver circuit we use one photodiode as a main sensor. Photodiode receive the  data in the light and then converted into electrical signal. This electrical signal is coupled to the pin no 2 of the ic 741 amplifier through .04 microcfarad capacitor. Pin no 3 is connected to the zero voltage. For zero voltage we connect two resistance one from the positive line and second from the negative line to the pin no 3 for a zero reference voltage. Output is available on the pin no 6 . Output signal which is available on the output pin is further amplify by the transistor circuit and then this signal is . Now signal  is connected to  speaker  through  capacitor in series circuit.

 

Testing

To test the circuit, plug the transmitter connector into the mains A.C . Turn on power to the amplifier through battery and the tune the receiver for maximum gain. Now turn on the both transmitter and receiver and make sure of the ferrite rod as the capacitor 104pf other end is having high voltage 220V A.C. Tune the transmitter and receiver for same frequency to lock the PLL  output to minimum distortion as sounded through speaker.

                                  To test communication between receiver and transmitter  simply  transmit through mic we get output  at the receiver speaker.

 

 

Parts List (PLCC):

Component

   Value

                     Description

       R1

1k

1/4 W resistor

C1-5

0.1uF

Capacitor (Ceramic)

U1

NE 565

RS-232 line driver

U2

BC 548

NPN TRANSISTOR

U3

2N2222

NPN TRANSISTOR

D1-2

1N4001

Power diode

P1

MIC

Photo-transistor

V1

SPEAKER

8 OHM

D1

OA 79

Diode

.

.

9V battery clip

.

.

DB-9 female connector with back shell.

.

.

2 m shielded 3-core cable.

.

.

Switch

Um91214

.

Dtmf encoder

8870

.

Dtmf decoder

 

 

 

 

 

IN this circuit we use two  circuit one is dtmf generator and second is operational amplifier. In the dtmf generator circuit we use ic um 91214 as a dtmf generator. Working voltage of this ic is 3.3 volt dc. So that we use one 3.3 volt zener diode as a regulator and provide a regulated power supply to this circuit. Output signal is available on the pin no 7 . this output signal is coupled to the input of the amplifier through selector switch. One 3.58 mhtz crystal is connected to the pin no 3 and 4 to give a carrier frequency to the circuit. IN this mode we use 3.58 mhtz crystal  as a main carrier source of the dtmf generator.

 

All the switches are connected to the input of the dtmf generator to provide a multiple signals. All the switches are connected in four rows and three coloum. When we press any key then one row and one coloum is activate automatically.

 

Data from the dtmgf generator is further connected to the pin no 2 of the ic 741 through capacitor .04 micro farad. Here capacitor block the dc voltage and pass only signal to the amplifier circuit. Pin no 6 is the output pin no of the ic 741. Pin no 3 is connected to zero voltage through voltage divider circuit. Here we use two 10 k ohm resistor as a voltage divider components. Two 10 k ohm resistor provide a zero reference voltage to the pin no 3 of the ic 741. Output of the ic 741 is further amplify by the two transistor circuit. Here we use one is npn and second is pnp transistor . Collector of the npn transistor is connected to the positive voltage and collector of the pnp transistor is connected to the negative voltage. Output of the transistor is available on the emitter point and this output voltage is connected to the laser diode through one current limiting resistor and one zener diode.

 

Analogue signal from condenser mike is also feeded to the input of the op-amplifier using selector switch. Condenser mike convert the sound signal into electrical singal and this signal is  coupled to the pin no 2 of the ic 741 through .04 microfarad capacitor. Resistor 10 k ohm provide a dc voltage to the condenser mike.

 

Gain of the amplifier or ap-amp is depend on the feedback connec mmmmted to the circuit. In this project we use one 10 k ohm resistor in series with the  100 k ohm variable resistor. With the help of this variable resistor we control the gain of the op-amplifier.

 

Now whatever we speak or  press the switch this data is  superimposed on the light of the laser. Laser respond this signal and then this signal is focus on the photodiode  in the line of sight.

In the receiver circuit we use one photodiode as a main sensor. Photodiode receive the  data in the light and then converted into electrical signal. This electrical signal is coupled to the pin no 2 of the ic 741 amplifier through .04 microcfarad capacitor. Pin no 3 is connected to the zero voltage. For zero voltage we connect two resistance one from the positive line and second from the negative line to the pin no 3 for a zero reference voltage. Output is available on the pin no 6 . Output signal which is available on the output pin is further amplify by the transistor circuit and then this signal is . Now signal  is connected to  speaker  through  capacitor in series circuit.

 

 

 

Applications:

 

Already Implemented In Bhakhra Nangal Dam.

DTMF signal Transmission.

Controlling devices .

Voice and Data transmission  using DTMF technology.

 

Uses:

Easy to implement

Reliable,

Low cost,

 

 

 

 

 

 

 

 

 

 

 

 

 

Planning

 

STEPS

TIME

RESPONSIBILTY

PROJECTS SELECTION

 

 

CIRCUIT AND THEORY ARRANGEMENT

 

 

CHECKING AVAILABILITY OF COMPONENTS

 

 

TESTING CIRCUIT

 

 

PCB DESIGN

 

 

COMPONENT INSERTION AND SOLDERING

 

 

TESTING

 

 

REWORK  OR TROOUBLE SHOOTING

 

 

 

Bibliography:

 

www.optoprojects.com/plcc.doc

www.ludhanaprojects.com/project.html

www.electrooptical.com/sensor.pdf