Simple Infrared (IR) Remote Control Circuit

This article shows you how to build a circuit that lets you control your appliances like lamps, TVs, fans with any remote control.

You can use an old remote you have lying around the house.

This is a fun project that makes using your electronics even more convenient.

What is a Infrared IR Remote Control Circuit:

An infrared IR remote control circuit is a type of electronic circuit that enables communication between a remote control unit and a device through infrared signals.

Infrared remote control is commonly used for various applications including controlling electronic devices such as televisions, DVD players, audio systems, and more.

The circuit typically consists of an IR transmitter in the remote control unit and an IR receiver in the controlled device.

Let us look into the comprehensive construction and operational details of this cutting edge system.

Circuit Description:

Parts List:

The fundamental components driving the functionality of this circuit are the timer IC 555 and the Decade counter IC 4027.

Additionally, we employ the IR sensor TSOP1736 to capture infrared rays from the remote control.

Acting as an electro mechanical switch the single pole double throw SPDT relay plays a pivotal role in making and breaking the load circuit within the power supply.

The circuit operates efficiently on a 9V DC power supply.

This power source is directly channeled to the relay and simultaneously regulated to 5V using the positive regulator IC 7805.

The regulated 5V supply is then distributed to both the timer IC and the counter IC.

When the IR rays from the remote control fall on the TSOP1736 sensor, it generates a spike signal at 36KHz.

This spike signal serves as a trigger input for the timer IC 555.

In response to this trigger the timer IC produces a pulse output at pin 3.

The duration and duty cycle of this pulse can be adjusted by manipulating the values of the components R5 and C4.

The pulse output from the timer IC is directed to the decade counter IC 4027.

This counter IC in turn, produces a set output at pin 1.

This set output activates the Q1 transistor subsequently connecting the relay and initiating the flow of power to the load.

Crucially, the duration and duty cycle of the pulse output from the timer IC can be fine tuned by adjusting the values of the resistive and capacitive components R5 and C4.

It is essential to ensure that the pulse duration is at least 1 second.

In the event that the IR sensor continues to receive infrared rays during the counter outputs set condition the operation persists.

However, once the counter output switches to reset, the Q1 transistor is deactivated causing the relay to disconnect the load from the power supply.

Formulas and Calculations:

For an astable multivibrator circuit, determining the oscillation frequency (f) requires considering the values of the timing components (resistors and capacitors) which calculation is mentioned below:

1. Calculate the approximate time constant (τ):

τ = (R5 + R4) * C4 (assuming R5 and R4 are in series with C4)

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

2. Estimate the half-cycle time (t_half):

t_half = 0.693 * τ (considering voltage levels mentioned in assumptions)

t_half = 0.693 * 20 ms = 13.86 ms

3. Estimate the oscillation frequency (f):

f = 1 / (2 * t_half) (as frequency is the reciprocal of the time for one cycle)

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

Note:

The actual oscillation frequency may vary significantly from this approximation due to non idealities, transistor saturation periods and component tolerances.

Using more sophisticated analytical techniques or circuit simulation tools are frequently required for precise frequency determination.

Construction Steps:

• Identify and gather all the necessary components as listed above.
• Ensure the correct type of transistor is selected based on your specific application requirements.
• Place the timer IC 555 decade counter IC 4027, IR sensor TSOP1736, SPDT relay, transistor Q1, and positive regulator IC 7805 on the PCB.
• Connect the components using jumper wires adhering to the circuit diagram.
• Connect resistors R5 and capacitors C4 to the timer IC 555, allowing for the adjustment of pulse duration and duty cycle.
• Experiment with different resistor and capacitor values to achieve the desired pulse characteristics.
• Connect the output of the IR sensor TSOP1736 to an appropriate input of the timer IC 555.
• Connect the output of the timer IC 555 to the decade counter IC 4027.
• Connect the output of the decade counter IC to the base of transistor Q1.
• Connect the relay to the collector of transistor Q1 and the load to the relay.
• Fine tune the circuit by adjusting the values of resistors and capacitors to achieve the desired performance.
• Test the circuit with an IR remote control by pointing it at the IR sensor and observing the response of the connected load.
• Once the circuit is working as expected consider soldering the components onto a protoboard for a more permanent setup.
• Optionally, enclose the circuit in a suitable casing to protect it from external elements.
• Ensure all connections are secure and finalize the construction.

Note:

• Remember to refer to the datasheets of individual components for specific details and pin configurations.

Conclusion

This sophisticated simple infrared IR remote control circuit provides an effective means of remotely controlling home appliances through IR technology.

By understanding the interplay of components and their functions users can tailor the pulse characteristics to meet their specific needs offering a customizable and reliable solution for home automation.

References

Wireless Infrared Remote Controller for Multiple Home Appliances

Datasheet TSOP1736