7400 competition entry: World’s most useless machine

Check out Alex’s useless machine with a chain switch. It’s operated with 4 servos and uses 11 7400 logic chops. It’s his entry to the Open 7400 Logic Competition:

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.

Build something that uses or abuses a logic chip and get amazing boards, tools, and other swag. The Open 7400 Logic Competition promotes awareness of the basic building blocks of modern circuits. Devious geeks ignited the computer revolution with discrete logic computers, what can you do? Details and entry form here.

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  1. Hi DP, and Alex…
    I like this! I’ve sequenced motors like this but didn’t use logic gates… I’m just curious as to the control… is the schematic available? …or a simple explanation of the control? Are those servos or just motor/gearheads with a lot of limit switches?? Is Alex still around?
    I’d be glad to hear whatever anyone else would like to add…

    If anyone is interested, my project – Most Useless Robot Ever, is here:
    (I know… its got some minor jitter problems due to weight/small motor mismatch…)


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