Piecax the Poltergeist. A Troublesome Spirit in a Box.

Step 3 The Mechanics

The various parts are stuck on with contact adhesive (that’s the type where you apply a thin coat to both surfaces, wait a few minutes, then it sticks hard immediately you put the parts together.)  The sounder is glued to the lid so it picks up the vibrations directly as the top is tapped.

For the ‘knocker’ I used a small 3V DC motor with a piece of brass strip bent fixed to the shaft.  I bent this to shape with a pair of pliers so it was a push-fit onto the shaft.   Be careful as you push it on as the plastic back of the motor is likely to push out, so put a hard object on the end and push against that.

The motor came with a solar cell kit and had the plastic clip with it.  Alternatively you could use a piece of split overflow pipe with one side sanded down, or use double-sided sticky foam to attach the motor to the box.  Later on, I added solder to the end to give a good solid knock.  A bit of trial and error is required to give the best weight.