This
is the most popular IR Remote control circuit for home appliances like
lamp, fan, radio, tv etc to make the appliance turn on/off from a TV,
VCD or DVD remote control. It is very simple to build because of few
components and simple design.
The
circuit can activated from up to 10 metres. The 38kHz infrared (IR)
rays generated by the remote control are received by IR receiver module
TSOP1738 of the circuit. Pin 1 of TSOP1738 is connected to ground, pin 2
is connected to the power supply through resistor R5 and the output is
taken from pin 3. The output signal is amplified by transistor T1
(BC558).
The amplified signal is fed to clock pin 14 of decade
counter IC CD4017 (IC1). Pin 8 of IC1 is grounded, pin 16 is connected
to Vcc and pin 3 is connected to LED1 (red), which glows to indicate
that the appliance is ‘off.’ The output of IC1 is taken from its pin 2.
LED2 (green) connected to pin 2 is used to indicate the ‘on’ state of
the appliance. Transistor T2 (BC548) connected to pin 2 of IC1 drives
relay RL1. Diode IN 4148 acts as a freewheeling diode. The appliance to
be controlled is connected between the pole of the relay and neutral
terminal of mains. It gets connected to live terminal of AC mains via
normally opened (N/O) contact when the relay energises. you can use any
NPN transistor inplace of BC548. You can also use SL100 or any NPN
transistor lying around you.
The
delay depends on the C1 capacitor. Using higher value capacitor will
create more delay and using less value capacitor will switch the circuit
more than 2 times when you press a remote. Analyse the circuit by
placing the 10uf capacitor in place of C1 (100uf).
