Actually I wanted to equip the Calliope mini Bot with the trick presented here with a collision sensor. Unfortunately the range is a little bit too short for that.
Nevertheless, this is such a good thing that I would like to present it here as a small project.
There are certainly a lot of application cases in which this technology can be used.
How it works:
The measurement is made once with and once without flash. If a difference can be detected, an object must be present.
In the example, the detection is signalled by a rectangle on the LED matrix.
The range is approx. 4cm.