brake light switch
As seen in the prior transmission, the two brass screw heads go inside the tube to provide outside contacts- the brass washer (held LOOSELY by a small flat head screw) finishes the connection when the spring pushes it against the round heads. Now the set-up on the caliper is simple- the switch mounts to a bent piece of steel that is latched under the adjustment set of the cable for the brake. a short legnth of stainless steel necklas chain is attatched to the end of the orange fiberglass rod ans also to a tiny slipring- said slip ring loops onto the excess brake cable on the caliper. When the brake is relaxed, it pulls the rod down and interrupts the connection. When the brake is applied, it releases the rod and completes the connection, thus activating the light.
The photo shows the first such unith I built- different hookups, but same principle