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