why do you need one? It's pretty simple. You start with the outer rings that hold the leds, depending on what leds (single ones, strips, etc) you wanna use and decide how many sections you wanna have on that ring. Then you buy the equivalent amount of reed-switches and some pin-cables that have the "specific amount" of pins plus one for the positive battery terminal. Put your leds on the ring and start connecting each pin with a section, connect the positive with all of them. Then you go for the inner ring and connect the same amount of reed-switches in a circle and connect them all to the negative battery terminal on the one hand and to the equivalent section of the outer ring on the other hand, just have to make sure that each reed-magnet is connected to the section that beams at the front when this specific reed-switch passes the magnet. And if you want to make things easy, you connect the inner and outer rings with connectors.