PiscatawayLights

Electric Chair with sound an dimming Lights

The challenge of the electric chair was to not just screw together a makeshift chair and add some straps to it.  It is put together like a real heavy piece of furniture.  4x4 posts make up the legs and nothing is screwed together.  All of the assembly is mortise and tenon jointery including the 1x6 slats on the back.  All of the tenons are glued with my favorite Gorilla glue and then pinned in place with dowels.  Also, the 1 and 1/4 inch seat is held in place with dowels.

Building the frame

You could probably strap someone into this chair and electrocute them and it would still hold up.  In addition, on the wall next to the chair is an electrical box with a big lever on the outside.  When the lever is pulled, the light hanging from the ceiling over the electric chair dims as the sound of electrical arcing comes from the hidden speakers.  When the lever is pushed back up, the sound stops and the light comes back on full.

I don't have any clear pictures of the inner workings of the box but here is a quick overview of the circuitry.

The light over the chair is a metal clamp-on type light from Home Depot.  I removed the clamp and the part that holds the bulb and replaced it with a socket that holds a 12 volt auto backup light bulb.  It gives off enough light in a dimly lit room to create a good effect.  The wire runs to the prop electrical box and connects to a 12 volt circuit inside.  Pulling the lever down closes a switch built into the box.  This causes a couple of things to happen.  The switch directs some of the 12 volt current to another light bulb sealed in the electrical box.  This draws enough power to make the one in the lamp go dim.  Also, it trips a relay that triggers a board with a sound chip.  The board is a CAR/P 300 chipcorder from Cowlacious Audio Products.  Also, there is another relay that opens and closes one of the speaker wires.  This is partly because of the way the chipcorder works (it needs to reach the end of the recording and reset even if the "lever" is pulled into the off position) and also to insure the sound cuts off cleanly when the operator throws the lever off.

The electric chair will be killing people again this year at the Woodbridge High School Choir Haunted House fundraiser.