The Bluebird "Snake-B-Gone": a device to discourage snakes and other predators

This project came from the sad loss of nearly-fledged bluebirds to a large milk snake that lives in the yard. It is just a way to remind the snake to dine elsewhere......  The unit uses a car ignition coil driven by a small circuit (555 timer and power transistor) to generate flyback pulses at a 1.5 sec interval. The coil is protected from the weather by the jug. The pulses are conducted by the woven electric fence wire that is wound around the outside of poly pipe insulation slipped over the 1/2" EMT house pole. The 6V/1.2A*Hr battery got charged every 2 weeks just to keep it in good shape. With a ~20kV reminder, we have had no snake problems since installation. It is a bit ugly, but the Bluebirds didn't seem to notice. They like having it closely mowed around the house so they can see insects better. The unit, including the battery, has been fit inside a section of plastic pipe with a cap on the upper end, the HV wire still trailing out the bottom; looks a bit nicer and is more durable. The blue plastic box stuck to the side of the coil with acrylic caulk houses the electronics. Schematic here.


Wire on Insulation Pulser on fiberglass pole Spark coil and circuit box uncovered