The frame is similar in shape to a sawhorse. At the top is a shaft with 17 sprockets. One of the sprockets is attached to a chain which connects it to a motor affixed to the bottom of the unit. Another sprocket has a chain that goes to a mechanical revolution counter at the left side of the unit. The remaining sprockets have loops of bicycle chain of varying lengths. In each chain, some of the pivots have been replace with screws with long tails. There is a micro-switch mounted above each of these chains which is activated when one of the long screw tails passes by. The frame that the switches are attached to flips up. There is a blue push button mounted on the front of the frame halfway up. There is a 14 V power supply attached to the bottom of the unit. The power cord is separate and attached to the bottom of the unit.
