IR Remote Control Switch Using CD4017 IC

          This is a simple IR(Infra Red) remote control switch based on IR sensor module, NE555 timer IC and CD4017 decade counter.The circuit was successfully tested and found free of errors.

         This is the schematic.

 Circuit Description

           The circuit was designed to be powered by a 5 v supply. Thus a 5 v relay is used to control the target circuit. You can use any kind of common IR sensor module which is used for TV or radio. So you can use that remote controller to control the relay.

          In response to the IR signals emitted  by the remote controller, the IR sensor module produces a train of electric signals. That is a digital signal. It is then fed to the pin no:2 of NE555. Operating as a mono stable multi vibrator, the NE555 circuit prevents all the digital signal from the IR sensor module passing to the pin no:14 of CD4017. Instead, NE555 is triggered with the very first falling edge of this digital signal. With thtis triggering, pin no:3 of NE555 goes high wich is last for a time duration determined by the R3 and C2 circuitry. It is around 500ms. For that time NE555 becomes insensitive to trigger signals.So NE 555 outputs a positive impulse keeping at least a gap of 500ms. Therefore whatever the frequency of triggering signal, once triggered, NE555 is unable to output a signal until 500ms is passed.

         Here CD4017 acts as a Flip-Flop. To improve the reliability of the circuit, an auto power on reset circuit has been built around T1 transistor. That is every time when  the circuit is powerd on, the circuit goes to the reset state. In the reset state the pin no:3 of CD4017 goes high lighting the LED1; the standby indicator. When the CD4017 is clocked once, pin no:3 goes low and pin no:2 goes high energizing the relay.If  another signal after 500ms clocks CD4017, again it goes to reset state. This operation goes on and on as long as IR signal is received.

Special Features

1. No multiple clocking of CD4017 per button click due to the circuitry based on NE555.
2. Reliable power on reset state maintained by the Auto Power On Circuitry.