This mechanism uses an 8mm threaded rod supported on each side by two 16mm outer diameter bearings driven by a small high-torque copper motor (both connected with the provided connector glued on the threaded rod and press fitted on the D-shaft of the motor) to move a clicker arm back and forth along the groove in the main structure. The clicker arm clicks on limit switches placed along the dovetail rails with the use of the limit switch housings. Each limit switch can be precisely positioned and fixed in place with a screw. The motor housing keeps the motor from turning instead of the shaft and must be glued on one end of the mechanism. This system was used paired with relays to allow a complete programmable robot to be driven by timing-based programming, only with no semiconductors.