[ENTRY] World's Most Useless Machine

[Alex555]

This is a last minute (and very useless) entry. I wanted to make something that shut itself off, but I wanted it to be different than all of the other useless machines out there. I also wanted it to be fairly complicated for this contest. The result is an arcade shaped device that has one of those switches that your fan or grandmother's lamp might have, with an arm, gripper, and two doors to conceal the arm. There is a total of four servos controlled by eleven 74xx chips on a wire-wrap board. The servos are controlled by a 555 timer circuit, a decoder, diodes, and four dip switches. The dip switches select which servo is driven, and a resistor is switched into the circuit. A '161 controls the decoder, giving sixteen possible sequences, of which thirteen I used. I did not actually use the grandma-style switch, just the chain that I attached to a lever and a spring and used optical switches to trigger the circuit, because they take far more torque to switch than my servos could supply. The case is made of hardboard, and has a bunch of screws that were actually from plastic things I 'recycled'. Some sides of the case are off to see the insides. I did not prototype the wire-wrap board to save time, and I also have not fine tuned the resistor values so it currently likes to clunk into itself. Now it's off to clean my desk, which you can also see in the video.
http://www.youtube.com/watch?v=TG-n48N2 ... tube_gdata

[matseng]

This is kinda neat. But I'd like to have more doors, arms, servos and moving parts :-)

[Alex555]

Thanks. And I wish you didn't say that, because now I have to make some extremely over complicated thing next year. Maybe I will put my pile of 145 motors (I counted) to good use. 1:^)

[t0mpr1c3]

Nice job. Just another 134 or so motors to go then. An even more Heath Robinson useless machine would be very cool. Perhaps one that incorporates pIng pong balls, fountains, log plume, shuttlecocks. a record player mechanism... ;)

[Alex555]

Well, college is in four years, so that lets me use 36.25 motors per year so I do not have to leave any behind. By the way, whenever you get the chance, put 30v through a cd motor. The coils handle it, the bushings can't. :-)
Back on topic, I will fix up the resistor values and complete the case after the competition is over.

[Alex555]

I fine tuned the resistors, fixed it up, and made it work every time. And now, its USB powered! I actually grabbed a small 5v supply from my box of wall warts, and apparently it turned out to be a 110v to USB converter with a cord stuck in it. The cord comes from the most useless possible spot (on accident again, I thought the back went on the other way) but decided not to fix it because it just makes it even more useless. Nothing like a convenient one foot cord. And ping pong balls are very flammable.

[Alex555]

Nooooooooooooo! That was my cell phone charger!

[techhobbit]

Alex, nice job! I was curious as to the control method you used, thanks for the explanation.
Definitely one of the most useless machines I've seen! (...that's a compliment!)
techhobbit