Remote Control Circuit Using KT3170


Posted on Feb 6, 2014

This circuit is which enables switching on` and off` of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls. The circuit described here can be used to switch up to nine appliances (corresponding to the digits 1 through 9 of the telephone key-p


Remote Control Circuit Using KT3170
Click here to download the full size of the above Circuit.

ad). The DTMF signals on telephone instrument are used as control signals. The digit 0` in DTMF mode is used to toggle between the appliance mode and normal telephone operation mode. Thus the telephone can be used to switch on or switch off the appliances also while being used for normal conversation. The circuit uses IC KT3170 (DTMF-to-BCD converter), 74154 (4-to-16-line demulti-plexer), and five CD4013 (D flip-flop) ICs. The working of the circuit is as follows. Once a call is established (after hearing ring-back tone), dial 0` in DTMF mode. IC1 decodes this as 1010, ` which is further demulti-plexed by IC2 as output O10 (at pin 11) of IC2 (74154). The active low output of IC2, after inversion by an inverter gate of IC3 (CD4049), becomes logic 1. This is used to toggle flip-flop-1 (F/F-1) and relay RL1 is energized. Relay RL1 has two changeover contacts, RL1(a) and RL1(b). The energized RL1(a) contacts provide a 220-ohm loop across the telephone line while RL1(b) contacts inject a 10kHz tone on the line, which indicates to the caller that appliance mode has been selected. The 220-ohm loop on telephone line disconnects the ringer from the telephone line in the exchange. The line is now connected for appliance mode of operation. If digit 0` is not dialed (in DTMF) after establishing the call, the ring continues and the telephone can be used for normal conversation. After selection of the appliance mode of operation, if...




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Tune six metres on your two metre receiver
Panner Waveform Generator
H2 PWM Generators
Radio alarm clock
signal Can someone break down how this receiver works
555 ic linear ramp sawtooth
stepper motor driver circuit diagram
Binary Phase Shift Keying (BPSK) modulation using CD4016 with Simulated output waveform
FM Modulator Circuit
DZW75-48/5050II input circuit
The Sound Square
Voice remote control switch circuit
The PC CPU overheating language caution circuit diagram
Common mode signal of emitter-coupled differential amplifier circuit a



Top