How to ON/OFF LEDs using an IR transmitter and receiver

ir transmitter and receiver

Today we are going to share with you How to ON/OFF LEDs using an IR transmitter and receiver. This is a very basic but most important project for an electronic learner. So, are you interested in it? let’s go start.


≡ What is an IR LED?

IR led is an LED that emits infrared light. That means it reduces the infrared frequency that’s invisible to us. The wavelength of this frequency is 700nm to 1mm. The IR LED looks like a normal led. similarly, it has focused, reflected, polarized like a LED.  It takes a maximum current of 20mA and the maximum voltage is 3 volts. Note that, it takes the minimum switching voltage is 2.7V.

The IR LED range is some cm to a few fits. it’s basically dependent on manufactures. It is normally TSOPXX packages like TSOP1730, TSOP1738, TSOP1740. The last two digits represent the frequency rate in kHz.  The element of IR led is gallium arsenide, aluminum gallium arsenide, etc.

IR led transmitter

≡ What is a photodiode?

Generally, a Photodiode is a semiconductor device that converts the light into current based on the mode of operation of the device. Some photodiodes will look like LEDs. Also, it has two terminal like anode and cathode. when photon energy loaded the diode, it makes a couple of electron-hole that’s called the inner photoelectric effect. after some process, it produces a voltage.


≡ An appliance which is the requirement for this project

To make this project, we need some components. The below this section, I describe a list of components that are needed for this project. Let’s collect materials below the list.

  • Project Board
  • LED
  • Resistor
  • IR LED
  • Photodiode
  • Connecting wire
  • 5V DC power supply


≡ Schematic Diagram

ir transmitter and receiver

≡ Description

Here the positive terminal of the transmitter and the negative terminal are connected to the ground or zero volts through a 270-ohm resistor from VCC (+5volts). On the other hand, the negative terminal of the IR receiver is connected to the positive, and the positive end is connected to the ground by a 3.3 k ohms resistor of the transistor base.

Here the IR transmitter and the receiver are parallel to each other Since the current is flowing from the positive end of the IR transmitter to the negative terminal , the transmitter is producing radiation here. The IR receiver is a photodiode whose electron flow is dependent on light. Keep in mind that both the transmitter and the receiver receive face to face, which is a lot like a light. But since the transmitter and receiver are not facing here, the receiver is not able to receive the radiation.

So when an object is placed on top of both, the radiation from the transmitter reaches the receiver due to the reflection. When the receiver receives any light a high voltage flows through it but here we need a very small amount of voltage as the transistor base. Due to which we have reduced the current using a resistor of 3.3 k ohm and given the transistor base.

On the other hand, the anode of an LED is connected to the positive terminal through a 270-ohm resistor and the cathode terminal is connected to the collector of the transistor, and the emitter is connected to ground or 0 voltage. The end of the LED always has a positive voltage. At the same time, when the transistor current is turned on, the LED at the terminal of the cathode ground is zero, so the LED is turned ON.

If you follow this article step-by-step, I hope you ensure your circuit design and make it probably. If you face any problem, please contact me. I will try to solve this problem. For more articles follow this site. Thanks for reading!

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