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Infrared obstacle sensor

Tells whether something is right in front of it, a few centimetres away: for robots that avoid walls.

The test program

Test this part on its own before you build the rest: if it works alone, the rest is built on something you know works.

10 LED red, off
20 IF SENSOR("obstacle")=1 THEN LED red, on
30 WAIT 100
40 GOTO 10

What you should see: Bring your hand within a few centimetres of the sensor: the red light comes on.

▶ Try it in the IDE

What to buy

  • IR obstacle sensor

How to wire it to an ESP32-S3

  1. OUT → ESP32-S3: GPIO41
  2. VCC → ESP32-S3: 3V3
  3. GND → ESP32-S3: GNDCommon ground: this link is mandatory.

If it does not work

The program runs but nothing happens
The sensitivity screw is set wrong, or sunlight confuses the infrared. Turn the screw on the module until its LED lights with your hand at 5 cm; try away from the window.

What you can adjust

  • The distance at which it triggers: the screw on the module.

Which boards it works on

  • ESP32-S3 Freenove: yes
  • Nordic nRF54LM20 DK: yes
  • Arduino UNO R4 WiFi: yes