Ive just knocked up a relay prototype for the RC car ive got and its working fine, now just to wire the connectors to the car for it and it should allow some basic control over the speed of the robot once its finished. THe relay is buffered from the viper with a 1kohm resister feeding a pn2222 transistor which in turn feeds power (5v) to the relay coil. three pins on the front edge of the board are the common and open closed terminals, only two will be utilised in this project
