Here are a few circuits that are relevant to robotics.
Please let us know if you find them helpful or if you have circuits that you would be willing to share.
We have two circuit diagrams that will help with the CAT5 rule for Prairie Sumo
You will need to find four SPDT relays whose contacts can handle the current needed for each motor. e.g. if your motor draws 1.2 amps at free speed and 1.9 amps at stall then choose a relay with at least a 3 amp capacity (one and a half times the stalled draw).
* If your motor and the coil in the relays are the same voltage then click here .pdf 178 Kb
* But, if the motor (or the battery voltage) is much higher than the rated coil voltage then click here .pdf 204 Kb
Note* The heavier lines should use 18ga wires and the thin lines can use 24ga wires.
Here is an introduction to building and programing an autonomous Line Follower robot. click here
How an autonomous Sumo robot can sense the edges and change direction. Click here to download the pdf file (69KB) Autonomous Theory and Circuit. Written by Colin Mantay and endorsed by the Manitoba Robot Games, this well written document explains the electronics behind the Autonomous Sumo Robot and comes with full schematics.