James Beam
Fall 2001
Create an engaging interaction using only a potentiometer and a servo.
James Beam was just a one week project to demonstrate my knowledge of basic programming and electronics.
Physically speaking it is a balance board, made from two sheets of plywood & a dowel... and a paper shadow puppet on the end of a stick attached to a servo. Although not set up for the video, the shadow puppet would be used to cast a 1/2 scale shadow a few feet in front of the user.
As the puppet leans to one side after perhaps a night of too much Jim Beam the user has to counter his movements in order to keep him upright. The puppet recovers, but then over corrects and so the user has to guide him back to a vertical position.
This continues to get more and more difficult until the motion of the puppet is just too fast and he falls all the way over. The game then resets for the next player.
Some details of the project
The intent was to use a servo motor which rotates to a specific position based on the length of a pulse it recieves. A short pulse would cause it to rotate to 9 o'clock (if you picture it like a hand on a watch) and a long pulse would rotate it around to 3 o'clock. This allows the microcontroller to send a pulse to the servo and then ignore it as it goes off to complete other tasks.
As it turns out the servo I found was actually just a DC motor and a potentiometer so I ended up coding a custom servo subroutine that acted as a sort of analog servo mechanism. It was more work in the long run, but gave me more control over the behavior of the mechanism, and in this case the microcontroller didn't have all that much to do.
Conclusions
In a future version I would probably use a tilt sensor instead of the potentiometer. And using a real servo might make the piece more stable. The documentation video is also a bit dark.
Video documentation
3.4Mb - 1min 30 Sec
