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OPTICAL FIBRE CONTROL SYSTEM.

 

 

In this project we show that how we control the mulitpal control system using one wire system. To control one wire system is a smart control system. We can use the same technique for control upto 100  controls. There is only one wire between from transmitter and receiver circuit. We use this concept in control panels, remote control circuits.  Optical fibre control systems.

 

IN this project we use one DTMf generator circuit and one receiver circuit. DTMF generator circuit transmit the signal to the receiver circuit. Receiver circuit receive this signal and then control the electrical appliances circuit  with the help of the relay coil.

 

DTMF GENERATOR CIRCUIT.

From the dtmf generator circuit we generate a  dtmf tones from one dtmf generator circuit .

In the dtmf generator circuit we use ic um 91214  as a main dtmf signal generator.  We use total 12 switches as a input data to the um 91214 and output of the 91214 is connected to the neutral line through  .01 capacitor.

 

 

DTMF CODE GENERATOR CIRCUIT.

 

In this part of the  project we use one  dtmf generator ic. We use ic um 91214 ic to generate a dtmf code for different multiple switches,. All the the 12 switches are connecte4d to the  ic 91214 ic

we use only 12 keys from this  16 keys matrix.  We use  0 to 9  keys  and star and hash keys if we require a 12 input keys. But in our project we use only 10 keys for this project operation.

Pin no 6 of the um 91214 is connected to the positive power supply. On this pin we provide a 3 volt power supply so we connect a one zener diode , resistance and capacitor circuit to provide a zener regulation of 3 volt DC.  One crystal is connected to the pin no 3 and 4 of the ic um 91214. here we use 3.58 Mhz crystal as a main generator of  carrier frequency. All the switches are connected to the  um 91214 in the four rows and three  .coloum. All the switches are connected in the um 91214 in the matrix formation. Pin no 12, 13 and 14 is connected to the  coloum and pin no 15,16,17,18 is connected to the  coloum. Output signal is available on the pin no 7 of the  ic um 91214 . Output from the dtmf generator is now connected to the op-amp circuit and with the help of the op-amp circuit we get a light output. This light output is now sufficient to control optical fibre system. If we want to use a single wire system then instead of the optical fibre we use a single shield wire system.

 

 

Output of the optical fibre system is  now connected to the photodiode circuit. Photodiode convert this signal into  electrical signal and this signal is futner connected to the   8870 ic. This ic is dtmf decoder ic and dtmf decoder decode the signal and converted into bcd signal.. . Ic 8870 is a single chip dtmf  receiver incorporating switches capacitor filter technology and an advanced digital counting averaging alogorithm for period measuremen

 

 

 

 

 

 

Output  from the  8870 decoder is further connected to the ic 74154. Ic 74154 is bcd to decimal decoder

 

 

bcd from the  8870 is available on pin no 11,12,13,14 and this output is further connected to the pin no  20,21,22,23 of the  ic 74154. Pin no 18 and 19 of the ic 74154 is enable control of the circuit. In our project we connect a one npn transistor to this point. Collector of the npn transistor is connected to the  pin no 18 and 19 of the ic 74154 to provide a positive voltage on this point. Pin no 15 of the ic 8870 is a acknowledgement of the dtmf signal, when dtmf signal is available on the pin no 15 then  with the help of this dtmf signal we switch on the npn transistor and  further npn transistor provide a negative pulse to the pin no 18 and 19 of the ic 74154 and decimal signal is available on the  output pins. Here we use only 10 output of the ic..

 

 

 

Output  from the  8870 decoder is further connected to the ic 74154. Ic 74154 is bcd to decimal decoder.

 

bcd from the  8870 is available on pin no 11,12,13,14 and this output is further connected to the pin no  20,21,22,23 of the  ic 74154. Pin no 18 and 19 of the ic 74154 is enable control of the circuit. In our project we connect a one npn transistor to this point. Collector of the npn transistor is connected to the  pin no 18 and 19 of the ic 74154 to provide a positive voltage on this point. Pin no 15 of the ic 8870 is a acknowledgement of the dtmf signal, when dtmf signal is available on the pin no 15 then  with the help of this dtmf signal we switch on the npn transistor and  further npn transistor provide a negative pulse to the pin no 18 and 19 of the ic 74154 and decimal signal is available on the  output pins. Here we use only 10 output of the ic..

 

Output of the ic 74154 is active low. So to convert this  active low output in to active high we use  inverter ic. Here we use ic 4049 as a hex inverter and with the help of this hex inverter we convert the active low output in to active high output with the help of inverter logic

 

 

 

Output of the inverter is now positive  signal but output of the inverter is still in pulse form. To convert this pulse into  on/off signal we require a  flip flop  circuit . With the help of flip flop circuit we convert the pulse logic into high  or low logic with the help of flip flop circuit. Here we use  ic 4013 as a flip flop circuit. Output of the flip flop is further connected to the relay driver circuit.

 

 

ic 4013 is dual D type flip flop circuit. Pin no 14 is connected to the positive supply and pin no 7 is connected to the negative supply. Pin no 3 and 11 is the clock input pin . Data pin  os pin no 9 and pin no 5. Output signal is available on the pin no 13 and pin no 1 of the ic 4013 flip flop.

 

In this project we use total 5  ic 4013 as a relay driver circuit. With the help of this five flip flop we  control total 10 different electrical appliances with the help of the relay driver circuit.

 

If we want to control the relay with the help of flip flop then we use npn transistor between flip flop and relay circuit . Here transistor work as a switch and with the help of this transistor we switch on/off the relay coil

 

 

 

 

 

7805 REGULATED POWER SUPPLY. FOR RECEIVER CIRCUIT.

 

 

 

In the receiver circuit we use full wave rectifier with 7805 regulator circuit and in the transmitter circuit we use bridge rectifier circuit  with 5volt regulator to regulate the voltage. Two high value capacitor is connected before and after the regulator to reduce the  ripple factor  of power supply.

 

 

 

 

 

Text Box:  
Text Box:  
OPTICAL DETECTOR
GSM Control of Electric and Electronic devices

 

 

 

 

 

 


 

required:-

Ic 741 Op Amp

IC 7805 Voltage Regulator

Diode 4004 Pn diodes

IC 91214 DTMF encoder

Ic8870  DTMF decoder

9 v Transformer 50mA

Optical fiber Singal mode

Resistances- 10k,1k,4.7k,220k

Capacitors- 0.1microfarad,00.1 microfarad,1000f,470f

Cupper clad board

Fecl3 for PCB design

Software Required:-

Window os

OrCAD

MS word

 

 

 

Introduction:-

In this project we will learn about how to use Optical fiber for communication purpose. Optical fiber need not to introduce. Everybody although he/she may be from any field know about Optical. Optical fiber as we know a reliable, low cost, flexible, large bandwidth communication medium.

In this project we can control any electrical appliances through DTMF dialing circuit for remote purpose .  When we want to control any electrical appliances through DTMF dialing circuit. Now again we press the switch on/off code to on/off any electrical appliances. With the help of this code unit is on and base unit give a acknowledge pulse for on and off separately.

DTMF Encoder Circuit:- in this circuit we will use IC91214 for no of devices. We will add keyboard with this IC. Ethis IC have option to generate 16 different pulses with different frequencies. These dual tone multi frequencies can be decoded at receiver side with IC8870 . these IC are esily available in market. We will use LASER for data transmission.

1.                 DTMF DECODER

In dtmf decoder circuit we use ic 8870 ic. IC 8870 is a dtmf decoder ic. IC 8870  converts the dual tones to corresponding binary outputs.

 

DTMF SIGNALLING. Ac register signaling is used in dtmf telephones, here tones rather than make/break pulse are used fro dialing, each dialed digit is uniquely represented by a pair of sine waves tones. These tones ( one from low group for row and another from high group fro column) are sent to the exchange when a digit is dialed by pushing the key, these tone lies within the speech band of 300 to 3400 hz, and are chosen so as to minimize the possibility of any valid frequency pair existing in normal speech simultaneously. Actually, this minimisator is made possible by forming pairs with one tone from the higher group and the other from the lower of frequencies. A valid dtmf signal is the sum of two tones, one from a lower  group ( 697-940 Hz) and the other from a a higher group ( 1209-1663 Hz). Each group contains four individual tones.  This scheme allows 10 unique combinations. Ten of these code represent digits 1  through 9 and 0. . tones in DTMF dialing  are so chose that none of the tones is harmonic of  are other tone. Therefore  is no change of distortion caused by harmonics. Each tone is sent as along as the key remains pressed. The dtmf signal contains only one component from each  of the high and low group. This significaly simplifies decoding because the composite dtmf signal may be separated with band pass filters into single frequency components, each of which may be handled individually.

 

First ic of this section is ic 74154. IC 74154 is  bcd to decimal decoder. 74154 is active low ic. Pin no 20,21,22,23 is connected to dtmf decoder ic.

Pin no 18 and 19 of this ic is connected to the collector of one npn transistor Base of the npn transistor is connected to the pin no 15 of the ic 8870. When dtmf decoder decode the signal at that time pin no 15 is on for a time and acknowledge the signal. This signal is fed to the  base of NPN transistor through 1 kohm resistor. When this signal is coming then 74154 is on and gives a output.

 

Then output of 74154 is active low. We will use IC 74ls 74  or transistors to invert the active low output. After that we will use flip flop & SCRs or relays to control & to give 220v Ac to devices for switching purposes.

 

 

 

 

 

 

 

 

 

 

 

 

Applications:-

 

            Networking between Computers.

            Because of large bandwidth used for telephone,tv network & internet comm..

            Communication between Buildings

            For sensing purpose- its use as a senser

            For Security purposes- To protect house or lockers

            For Military equipments- Because its a secure data transmission syatem

            For Medical machines- used as a sensing device

            For lightening purpose in decoration