The article discusses a simple IR remote control circuit which is configured for operating a DC motor in response to the switching made from a standard IR remote handset such as a TV remote or a DVD remote.

The connected motor can be moved either ways and also can be made to halt.

The circuit may be understood with the following explanations:

How it Works


As can be seen in the given circuit diagram, the sensor is any standard three pin IR sensor module which would typically respond to any TV IR remote handset.

When an IR (infra red) beam is focused at the sensor, the pin which is designated as the output becomes logic low. This situation persists as long as the beam remains focused at it.

The transistor T1 which is a PNP responds to this logic low signal and conducts switching the attached relay RL1.

The contacts instantly connect the instantaneous positive potential at the collector of the transistor to pin#14 of the IC1 which is wired as a flip flop circuit.

Assuming the initial logic sequence to be at pin#3 of the IC, the above triggering shifts the sequence to pin#2 of the IC, making it high.

This switches ON T2 and the corresponding relay RL2.

RL2 conducts and connects the particular wire of the motor to negative supply. Since the other terminal of the motor gets a positive from RL3, it starts moving on the set direction.

Now suppose, the sensor is given a subsequent trigger through the IR remote handset, the above process repeats and the output sequence shifts from pin#2 to pin#4 of IC1, which instantly switches ON T3 while switching OFF T2.

The above action reverts the relay connections forcing the motor to instantly flip its rotational direction .

With another subsequent trigger from the remote handset, the sequence bounces of back to pin#3, which is not connected to anything and results in switching off of the motor completely.

The inclusion of L1, C1 ensures that the circuits does not get influenced with spurious triggering of the sensor.

L1 can be experimented to get the optimal value so that it "grounds" only accidental stray external signals and not the actual IR signals from a remote control handset.




Parts List for the above IR (infra red) remote controlled motor circuit.


R1 = 100 ohms,
R2 = 1K
R3,R4,R5,R6,R7 = 10K

C1, C4,C6 = 100uF/25V
C2,C3, C7 = 0.22uF
C5 = 1000uF/25V
C6 = 0.22uF
L1 = 100mH choke
T1 = BC557
T2,T3 = BC547
D1---D7 = 1N4007
IC1= IC4017
IC2 = 7812
All relays = 12V/400 ohms/SPDT
sensor = TSOP1738

Motor = 12V Dc motor

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