Adjusting/Tuning 38kHz IR Proximity Sensor to sense a shorter distance

Just purchased the “38 kHz IR Proximity Sensor, Fixed Gain, Low Brightness” Sensor. I read that by tuning for 38, the sensing distance can be maximized or it can be detuned to shorten the sensing range. I am powering the sensor via a battery and need to adjust or tune the sensor for detection of a shorter distance. Does anyone know how to tune the sensor manually? I am using the right-angle header, so the sensor detects objects directly below the sensor, but it still has too high of a sensing range and I can’t seem to adjust it no matter what I do.
Am I doing something wrong? Thanks!

Are you adjusting the potentiometer on the receiver side?

Yes, I am trying to adjust the potentiometer to change the frequency and shorten the sensing range. How do I do this?

Looks like you have to tune the POT with a flat screwdriver and observe the performance. Let’s see what team pololu suggest.


What sensing range are you trying to achieve? Could you post pictures of your setup to give us a better idea of what you are trying to do?


I used a screwdriver to tune the POT. This should shorten the sensing range. Thank you. However, Is there a way to also tune the radius at which the sensor detects from all direction? I need to install the sensor in a narrow tube and detect only directly beneath the sensor for what I am trying to do, but it keeps detecting the sides of the container.

The product description says-“The sensing angle is relatively wide in both directions. The high-brightness version in particular might require extra consideration when mounting to prevent seeing surfaces parallel to the sensor’s line of sight. For many applications, additional shielding can be used to block undesirable sensing paths, such as reflections off of the ground, or to reduce interference from ambient lighting. When applying shielding, keep in mind that reflection off the shielding itself can cause undesired activation of the sensor.”

There is no adjustment for tuning the field of view, though you can try to restrict it using some additional shielding as rpiloverbd mentioned.

Alternatively, you might try getting a second unit and using one as an emitter and one as a detector. On the detector unit (inside the tube), you can disable the IR emitter using the ENABLE pin. Then, the second unit can function as the emitter and be located to a different location, such as on the outside of the tube. So, the sensor should only be triggered when IR light from the emitter gets reflected back down the tube.