I Called this BEAM Robot "The Beatle". My intention is to make this BOT to very very tiny and pretty size and convenient for buying the materials in Thailand. This Robot can walk follow the light beam. it used 4 Phototransistor sensors for forward and backward . The IC 74HC14 is used to opamp the photo sensors and driven 2 motors. The wheels were modified from small 3V gear-moters. The powersupplyis used 12 Vdc battery on 23A and use 78L05 regulator to reduce to 5 Vdc. Email: hs7nbl@hotmail.com