Investigator behaviour (Cyan)


The Thymio follows a black track. If the track is circular, as in the video clip above, the Thymio will follow it indefinitely. If the track ends, the Thymio will turn looking again for the track. If it finds the track, it will continue to follow it.

The track must be at least 4 cm wide with high contrast, the best is black on white.


The detection levels can be calibrated when the 'Investigator' mode is activated:

  • To calibrate the black level, with Thymio's ground sensors positioned over the track, press both forward and backward arrow buttons simultaneously.
  • To calibrate the white level, with Thymio's ground sensors positioned over the white area, press both left and right arrow buttons simultaneously.

High environmental light protection

A high environmental light incidence (e.g. outside) or at direct sun exposure the sensors may be blinded and Thymio will not properly detect the track. Remedy: Put Thymio in the shadow or tape a piece of paper on its frontside.

Tracks to be printed

A4 PDF file with straight track
A4 PDF file with s-curved track
A3 PDF file with figure 8 track
A1 PDF file with a more complicated track

This Aseba .aesl file contains the source code implementing this behaviour.

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