In today's time, IR communication is widely used in many devices in different areas to control them wirelessly. IR Technology has various useful applications in our day-to-day life appliances such as TV remotes, ACs, infrared cameras, and temperature sensors. 

But what if in case your IR remote stops working and you won't able to control your devices? In such scenarios, you will probably think your device is not responding but firstly, you need to check for your IR remote to troubleshoot such issues.

In this project, we're creating an IR Remote tester circuit using the TSOP38238. What makes this project interesting is that it doesn't rely on a microcontroller to check your IR remote. The circuit is made with a few components which are also not expensive. It lets you test both the overall functionality of your remote and the response of each button on it. In the previous article, we learned how to interface the TSOP38238 IR Receiver with Arduino. 

Most of the commonly used remotes work on 38khz IR frequency hence we are using an IR receiver of 38khz to be easily compatible with devices.


Components Required


TSOP38238 IR receiver

The IR receiver module has assembled an inbuilt Photodetector preamplifier and Internal filter for PCM frequency in one package.

IR receiver module functional diagram

When the IR signal is received by the photodetector, the noise inside the signal is suppressed by the Filters by allowing a particular band filter. The filtered signal is then demodulated to message signals which are then amplified to recover the gain losses of the signals.

Modulated and Demodulated Signals on Oscilloscope

The Above image shows the Modulated and demodulated signals at two different channels on an oscilloscope. The upside signal is modulated which has the Carrier wave whereas the below one is the demodulated data signal which is the output signal.

The output signal can be easily decoded using any microcontroller by following certain protocol techniques like NEC. But we won't need that for our project so we skip it.

The main phenomenon we will be working on is that the TSOP38238 sensor reacts to incoming IR pulses or signals by causing its output pin to transition from a HIGH state to a LOW state. This pin returns to a HIGH state when the signal is no longer detected. In its default state, the output pin remains HIGH. The above image strictly illustrates this phenomenon of a TSOP38238 sensor.

TSOP38238 Pinout

The TSOP38238 has three pins:

  • Vs: Terminal Requires power input whose range is 5 V to 5.5 V.
  • GND: Terminal connected to the ground.
  • OUT: Pin used to output the demodulated signal which is preamplified.


  • Supply Voltage Range is from 2.5 V to 5.5 V
  • Required Low Power to operate about 3mA current.
  • Package supports Carrier Frequency 38KHz.
  • Output voltage is -0.3 to (VS + 0.3) V.
  • Output current is 5 mA.


TSOP38238 IR Remote tester circuit Diagram

TSOP38238 IR Remote Tester Circuit Diagram

In the above circuit, the +ve terminal of Led, Buzzer, and TSOP38238 are all commonly connected to a 5-volt +ve supply terminal whereas Led’s -ve is connected to a buzzer -ve terminal with 100-ohm resistance in series. The Buzzers -ve is connected to the TSOP38238 OUT terminal in continuation with 100-ohm resistance. And simply the ground of supply is connected to the GND of TSOP.

TSOP38238 IR Remote tester circuit


Demonstration of IR Remote Tester 

Turn on the supply to power the circuit, and press any button on your 38KHz IR Remote. The pulses received by the sensor are transmitted by Remote, hence the OUT terminal gets LOW which makes the circuit complete for LED and Buzzer. As a result, the LED and buzzer blink and beep respectively at the same time which indicates that the remote is working properly. And that’s how you can also check each button on the remote. The circuit responds each time you press any button.

IR Remote Tester

Hope you liked and enjoyed the project and learned something valuable from it. If you have any questions, you can leave them in the comment section below.

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