When you have perfected the use of snap switches as whiskers on your small mobile robot, then it's time to move up to a no contact method of obstacle detection.
The Lynxmotion IRPD coupled with a microcontroller is the next step in obstacle detection and avoidance.
User Guide
Lynxmotion Infrared Proximity Detector (.pdf 159 Kb)
This product was added to our catalog on Tuesday 06 March, 2007.