seth’s ITP site

William Tell’s Carnival Sideshow is a game that I made using a small dc motor connected to a target, which lights an LED when struck with the appropriate amount of force. The force is applied via a projectile, which is thrown by one player while another holds the target. The target spins utilizing the physical properties of a fly wheel allowing the generator to light the LED for the duration of its spinning.

The original design concept was to make a game that one could use tennis balls, or something of a similar weight, to throw at a target which used the kinetic energy when struck to light small LED. The model I had in mind was the old carnival booth where a clown would try to insult people into trying to hit a target, which would drop them into a pool of water. I planned on having a small tower clown face on the top and a target below. The idea was that when the target was hit, it would spin around causing a clown’s nose to light up using the kinetic energy from the ball hitting the target to power the light.

Originally I used a small toy car motor. Spinning it around with an attached arm I could get about 2 V in an open circuit. I could only muster up to a couple of mA if I really committed to spinning the motor. This wasn’t a particularly good ratio. I managed to right up a gear system out of rubber bands and round dowels. This apparatus did well in very contained experiments, but when applied to the machine it was rendered useless almost every time I played with it.

After being discouraged by the gearing system in my prior prototypes, I used a more robust fan motor. This motor made up to 6V and with a really good spin could get around 12-15 mA fairly regularly. The fan motor was much better for my purposes. I also built my target as a hand held object rather than freestanding piece. This made it much easier to fine tune. I attached the motor to the end of a stick and used screws around the end to tie the motor on with copper wire. Then I used a factory metal fan hex wrenched onto the motor and bent around the target shaft, then screwed in, to firmly secure the object.

The first few runs of experimentation were an absolute disaster. I kept destroying my prototypes using balls/objects that were dangerously heavy for in house play. There were also problems with the spinning. The flywheel developed after knocking the target out of my “playmate’s” hands a few times. Balancing the weight of the target made the machine much more easier to handle. Also with good contact the LED would slightly more than pulse. Because we hit the target holder so many times, which became part of the fun of the game, it was deemed “William Tell’s Carnival Sideshow”. It seemed an appropriate name for this kinetic prop which squinted on with conventional mundane projectiles, but would really light up if one were to hit it with a crossbow.