The electric motor is a hobby DC type. I have used a variety of these 3-6 volt brush type motors with success. I think the one in this example came from Electronic Goldmine and was probably less than a $1. There are many of these kinds of motors offered on eBay or surplus houses. One thing you should look for is good low end torque as these are direct drive. mj
You can also typically find screw drives with motors inside the sled positioning mechanism in CD drives(plus a ton of other cool bits and pieces like gears, encoders, photodiodes, magnets, and lasers of course). Though they do tend to be rather course pitch. I really dig your approach to constructing linkages and mechanisms, especially in this day and age of youngins just assuming everyone has a 3d printer, or extruded aluminum laying around(I blame the instructables crowd whos instructions amount to 'print this file, buy this sensor, tada now youre an inventor and you made a grossly misnamed, grossly incapable thing whos code you dont understand in the slightest!' blinding makers to the true ways of cobbling things together from essentially garbage like REAL hackers used to do). I still build prototypes out of popsicle sticks, wooden BBQ skewers, and scrap plastic or metal from old disassembled items. Why throw away perfectly good building material just because its not in a perfect factory standardized shape? Why cripple creativity by only seeing what is intended for a purpose instead of opening the mind to the possibilities and characteristics of the material itself? I dont need a precision milled bar piece with holes every 5 cm, I just need a rigid, thin bit of material with holes here and here. And there is tons of material around everywhere that can fill that roll. While they're still waiting for their print bed to heat up, Im already wiring switches and LEDs about to close it up and start coding!
I have always tried to figure out how the original inventors/discoverers/engineers actually made things. No science supply stores to provide plastic fantastic! Making things and getting them to work requires the elegant thinking of those that have gone before. Having taught in schools with very little budget for "things" we were always relegated to make our own equipment. I'm not anti-cool gadgets (I also like Arduino and all the black box electronic plug-ins), but if we hope to ever inculcate a sense of ingenuity, drive, and persistence in STEM, kids ought to use some hand skills and walk in some of the footsteps of the giants that paved the way. Cheers!
