Little robot friendly, simple and robust based on Arduino UNO R3. It uses an Arduino UNO R3, an ultrasound detector HCSR04 and 3 servo motor SG90. Servo are fixed with plastic flanges Technical data: Dimentions: Long. 120mm | width. 80mm | High. 75mm Weight: 170g (without battery) Driving wheel diameter: 60mm Diameter of mobile: 25mm You can buy it ready to play (from Switzerland or France only) or electronical stuff on: http://www.chipandlove.ch http://www.chipandlove.ch/fr/home/107-chip-n-bot-v10.html The basic source Arduino code (Chip_n_Bot_V1.ino) is downloadable here: http://www.chipandlove.ch/fr/index.php?controller=attachment&id_attachment=2 Continuous rotating servo modification SG90 tutorial: http://todbot.com/blog/2009/04/11/tiny-servos-as-continuous-rotation-gearmotors/