Simple Infrared (IR) Remote Control Circuit

The article teaches how to build a circuit that can control fans, TVs and lights with any remote control.

An old remote control that is lying around the house can also be used.

This is a fun do-it-yourself project that makes this electronics hobby much simpler.

What is a Infrared IR Remote Control Circuit:

An electronic circuit known as an infrared IR remote control circuit allows a device and a remote control unit to communicate via infrared signals.

Televisions, DVD players, stereo systems and other electrical gadgets are controlled using an infrared remote control.

The remote control units infrared transmitter and the controlled devices infrared receiver generally make up the circuit.

Let us explore the complex layout and functioning of this modern technology.

Circuit Working:

Parts List:

The decade counter IC 4027 and the timer IC 555 are the essential parts that power this circuit’s working.

Also we can capture infrared rays from the remote control using the IR sensor TSOP1736.

The SPDT relay which functions as an electromechanical switch is essential for creating and breaking load circuits in power supplies.

When powered by a 9V DC source the circuit functions effectively.

The positive regulator IC 7805 is used to simultaneously control this power source to 5V and supply it directly to the relay.

The timer IC and the counter IC are then both supplied with the regulated 5V supply.

The TSOP1736 sensor generates a spike signal at 36KHz when the remote controls infrared rays hit it.

The timer IC 555 uses this spike signal as a trigger input.

The timer integrated circuit generates a pulse output at pin 3 in reaction to this trigger.

By adjusting the values of components R5 and C4 one can modify the pulses duration and duty cycle.

The decade counter IC 4027 receives the pulse output from the timer IC.

At pin 1 this counter IC then generates a set output.

The Q1 transistor is activated by this set output which then connects the relay and starts the power supply to the load.

Furthermore, the resistor and capacitor R5 and C4 are adjusted to fine-tune the duration and duty cycle of the pulse output from the timer IC.

Ensuring that the pulse duration is at least one second is crucial.

The action continues if the IR sensor keeps receiving infrared radiation while the counter outputs are set.

But when the counter output goes to reset the relay disconnects the load from the power source since the Q1 transistor is inactive.

Formulas and Calculations:

For an astable multivibrator circuit measuring the oscillation frequency (f) needs to provide the values of the timing components i.e resistors and capacitors whose formulas are mentioned below:

Calculate the approximate time constant (τ):

τ = (R5 + R4) * C4

τ = (1000Ω + 1000Ω) * 10uF = 20 x ^10-3 s (or 20 ms)

Estimate the half-cycle time (t_half):

t_half = 0.693 * τ

t_half = 0.693 * 20 ms = 13.86 ms

Estimate the oscillation frequency (f):

f = 1 / (2 * t_half)

f = 1 / (2 * 13.86 ms) = 36.1 Hz

Note:

Transistor saturation times, component limits and non-idealities can cause the actual oscillation frequency to differ much from this estimate.

For correct frequency calculations its essential to use advanced methods of analysis or circuit simulation tools.

How to Build:

Follow the below mentioned steps for building Simple Infrared (IR) Remote Control Circuit

• Identify and gather all the necessary components as listed above.
• Make sure the transistor type you choose meets the needs of your particular application.
• The PCB should have the timer IC 555 decade counter IC 4027, IR sensor TSOP1736, SPDT relay, transistor Q1 and positive regulator IC 7805 placed on it.
• As shown in the circuit diagram connect the parts with jumper wires.
• The timer IC 555 is adjusted with pulse duration and duty cycle by connecting resistors R5 and capacitors C4.
• To obtain the required pulse qualities experiment with various resistor and capacitor values.
• Connect the IR sensors output TSOP1736 to the proper timer IC 555 input.
• Connect the decade counter IC 4027 to the timer IC 555s output.
• Wire transistor Q1s base to the decade counter ICs output.
• Connect the load to the relay and the relay to transistor Q1s collector.
• Fine tune the circuit by modifying the values of resistors and capacitors to reach the desired performance.
• Use an infrared remote control to test the circuit by pointing it at the infrared sensor and see how the connected load reacts.
• After the circuit functions correctly think about putting the parts onto a protoboard for a more long term configuration.
• If necessary cover the circuit in a suitable housing to shield it from the elements.
• Once the work is complete make sure all connections are safe.

Note:

• Do not forget to go through the datasheets of each component for pin configurations and other details.

Conclusion

Using IR technology this simple infrared IR remote control circuit offers a practical way to remotely operate household appliances.

By knowing the connections between parts and how they work together users can adjust the pulse characteristics to meet their own needs while still having a dependable and adaptable home automation system.

References

Wireless Infrared Remote Controller for Multiple Home Appliances

Datasheet TSOP1736