Home made remote tester using TSOP1738. This circuit helps to test the each button of the remote. When you press a button the led in the circuit blinks. The Remote control tester circuit uses the IC TSOP1738 for its working. This is an IR remote control receiver module which is embedded with a PN diode and a pre-amplifier to form one pack. This IC produces an active LOW state output and provides a HIGH +5 Volt at OFF state.

We all use remote control handsets for controlling various household devices such as TV, AC, Music systems, curtains etc, and sometimes we seem to have problems with these devices, or even a newly purchased remote controller unit occasionally seem to malfunction, and identifying the issue becomes quite difficult for us.

This simple 2 transistor circuit will allow you to check the response of any remote control handset and help you to verify whether or not it is working OK, or needs to be replaced with a new.

Most of the time a low battery or a loose battery connection becomes the main issue which causes a remote handset to malfunction, however if you have a new battery installed and still the device doesn't work efficiently then perhaps this simple remote tester circuit could be used for identifying the fault.

Using a Two Transistor Circuit

Circuit Diagram

Video Clip

A simple remote tester circuit using just 2 transistors can be seen in the above figure. The working of the design is self explanatory.

When the remote control handset's button is pressed and pointed towards the photodiode of the circuit, the photodiode begins conducting and allows a few mV to pass through it.

These tiny electrical signals in the form millivolts reach the base of the NPN BC547 which responds to these signals and in turn begins conducting. However, its amplification is significantly low at this stage.

Therefore another transistor in the form of BC557 is attached with the collector BC547 to enhance or boost the amplification to a level sufficient enough to illuminate an indicator LED.

The amplified signals from the photodiode ultimately is boosted to illuminate the attached red LED connected across the collector of the BC557 and the ground line.

The LED lights up and begins flashing as per the remote control's internal pulsed waveform or the programmed signal code.

The 1N4007 ensures some degree of filtration from stray signals and helps the LED to remain shut off during standby positions.

Still you may find the LED glowing dimly if an ambient light is incident on the photodiode, since all forms of white light will have a certain amount of infrared waveform which can affect the photodiode performance.

Using an Opamp Circuit

The above design can be also experimented with an opamp circuit as shown below:

Video Clip

The remote control tester above using an opamp also looks pretty straightforward.

An ordinary opamp 741 is employed here for the detection. It is configured as a comparator. Its inverting input pin#2 is used as a reference level, and is set by fixing the connected preset.

The photodiode can be seen connected across the the non-inverting pin#3 and the positive line.

The preset is adjusted such that in normal condition when no signal is being received by the photodiode, the LED at pin#6 stays just shut off.

This is actually very easy, just switch ON power and begin adjusting the preset to-and-fro, and set it at a point where the LED just remains shut-off.

Next, point a TV remote control handset towards the photodiode, press any of the buttons of the remote control, you will instantly find the LED blinking in response to the remote control's coded IR signals.

Using TSOP1738 IC

The TSOP17XX series infrared sensors are specially designed for IR remote control operations. Even our TV sets use this versatile and efficient device for sensing and decoding IR signals and for executing the necessary commands.

A simple remote tester can be built using the same IC, through the following schematic:

Again the remote tester design using a TSOP1738 appears extremely straightforward.

The connection arrangement of the TSOP IC is in its standard form, rest of the circuit is as simple as it can be. Just a couple of transistors are enough to get the circuit working in the most versatile way.

The great feature of this circuit is its immunity to noise and ambient light, not forgetting the sensitivity and range too. The detection range is actually awesome, you can point the remote handset to an opposite wall and still get the LED to respond efficiently from the reflected IR rays.

The aim of the above explained remote tester circuits is to show how a simple IR circuit can be used for activating an LED in response to IR rays from any ordinary IR remote control system.

The LED can be easily replaced with a relay for accomplishing more complex jobs as per a given application requirement, or as per user preference.

Have questions? You can put them forth as comments below, all your queries will be addressed ASAP.

[Click the image to enlarge it]

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Pin Configuration

Pin Number

Pin Name




Connected to the Ground of circuit



Typically connect to +5V, maximum of 6V can be given



The signal pin gives out the sequence based on the IR signal detected

TSOP-1738 Characteristics

  • Minimum and Maximum Input Voltage is -0.3 and 5V respectively. Typically +5V is used.
  • Can detect IR signals from Remotes (38kHz)
  • Operating current: 5mA
  • High Range and wide coverage area.
  • Will respond only to IR signals, due to high immunity against ambient light
  • Low power consumption
  • Has in-built pre amplifier
  • TTL and CMOS compatible

Note: Complete Technical Details can be found at the TSOP1738 datasheet given at the end of this page.

TSOP1738 Equivalent IR Receivers

SM0038, TSOP-17XX

Where to use TSOP-1738 Sensor

The TSOP sensor has the ability to read the output signals from home remotes like TV remote, Home theatre remote, AC remote etc. All these remotes will work with a frequency of 38kHz and this IC can pick up any IR signals process them and provide the output on pin 3. So if you are looking for a sensor to analyse, re-create or duplicate the functions of a remote then this IC will be the perfect choice for you.

Also keep in mind that this series TSOP-1738 will receive only 38Khz IR signals. All remotes in India will operate in 38Khz, kindly ensure if it is the same in your country.

How to test and use TSOP-1738 Sensor

The TSOP-1738 is an IR Receiver Sensor, which can be used to receive IR signals of 38Khz. The sensor operates on 5V and consumes around 5mA to operate. Normally the signal pin (pin 3) IC is connected to a microcontroller to analyse the IR signal received. But let’s consider that you just purchased the IC and you want to check it is working. To do those just connect your TSOP as shown in the test circuit below

Now use any IR remote that’s lying around in your home and press any button on it. You should notice the Green Led blinking each time you press any button. This is just to ensure that the sensor is working as it has to be. Now, you can proceed with any MCU or MPU to decode the received IR signal. Once the IR signal is decoded you can re-create it using an IR Blaster.

TSOP-1738 Applications

  • Receive IR signals
  • Decode Remote signals
  • Analyse, re-create or duplicate remote Signals
  • Wireless control applications
  • Receiver circuit for IR remote controls
  • IR Remote tester circuits

2D model of the component

  • четверг 30 апреля
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