Use a relay that has doublepole double throw contacts to apply opposite polarity voltages tothe rotos of a small DCD motor upon the throwing of a singleswitch. Include a seperate ON/OFF switch in order to stop the motor before changing directions.
The relay will be energized whenthe applied voltage is 12 V. The motor will either be a 9-18Vor a 3V.
As part of the design, providean indacation of the direction of roatation bu illuminating a REDLED when the motor is turning clockwise and a GREEN LED when themotor is turning counter clockwise