Sonic Device

I love 1950's science fiction movies about giant reptiles, giant bugs, and flying saucers.

The key to making this conversion is right here, the spring from a ball point pen.

And a plastic drinking straw.  I got a thin straw at a fast food place.

Just put the spring inside the straw and then slip the straw over the antenna on the radar dish and you are done.

You want a spring that is very tight to the straw.  I used dental floss to help pull the spring into the straw.

Thread the floss through the spring and then put both ends through the straw.

Pull the floss from one end of the straw, and push the spring from the other end, I used a bamboo skewer to help push.

I saved up springs for a few  years every time we had a pen die, it's spring was harvested.  The straws and the springs come in many sizes so you make have to play around a bit to find compatible sizes.

The truck is some old resin truck that was in the spares box and the dish was from a toy truck, I purchased a number of the radars a few years ago for this project and a few others.