MOBOT-PS20 is a miniature module of a photo-optical sensor based on a small distance sensor HSDL-9100 by Avago and an APDS-9700 system from the same manufacturer. Arrangement can be used as a presence sensor having output only with binary information, as well as a distance sensor with an analogue output to about 80 [mm]. The layout can be used, for example, in small robots as an obstacle sensor, and for detecting lines in LineFollower robots.