I took part in the Cosmobot Competition in March of 2011 with the 3 kg sumo robot “Albertito”.
Robotics
How to connect the Cny70 Sensors
The CNY70 used to be a very common sensor to detect surfaces.
H bridge based on relays
Nowadays almost all the H-bridges are based on MOSFETs, but some time ago it was not always like that.