This computer controlled mobile robot was built in three months. The Robot cost about 100$. You can control it by a computer program. The robot uses relays to move itself. The robot runs three hours by a 6V 3Ah accu. The parts: 1x ULN2803 1x CD4093 1x 7805 1x 555 7x LED 1x 2200uF 25V 1x 100uf 7x 100nf 20x resistor 2x motor direction change relay 6V 2x motor control relay 6V 2x6V motor with integral gearbox 7x screw terminal 1x 100x160 prototype board 1x 6V 3Ah lead accu 3m flat cable about 2m connectin wire 1x switch 2x Nikko wheel 1x wheel 9x cable tie etc... Email: eeroalk@dlc.fi