Abstract: A rotation control for a device to be rotated includes a variable speed DC motor having a constant rotational speed upon receiving a selected fixed voltage electrical input power from an adjustable electrical input power supply connected to the motor for supplying the selected fixed voltage. A switch circuit is connected between the motor and the power supply activatable in response to a first electrical signal to turn the motor "on" and activatable in response to a second electrical signal to turn the motor "off". A selectable frequency, regular interval electrical signal device is connected to the switch circuit to provide electrical signals to activate the switch circuit to turn the motor "on" at regular intervals. An encoder wheel is coupled to the device to be rotated and to the motor for rotation of the timing disk at a speed proportional to the constant rotational speed of the motor. The timing disk has a plurality of openings around the disk with predetermined spacing there between.