Computer Controlled Electromagnets

[dexwiz]

Not really sure where to post this but here it goes.

For Science Fair this year I am doing the density of ferrofluids when under the affects of varing strenghts of magnets. Anyone know where I can get a computer set up/magent for under $100 US that I could use. I don't need very strong magnets, just pretty exact ones. I need there to be about 25 settings.

[four4875]

could you build a psu capable of 25 different voltages, and switch between voltages to control magnet strength? any reason it has to be computer contolled? will it be pulsed or switched or something?

sorry i dont know of any commercial setups to do it, but if we know the requirements we might be able to figure out something that can do what you need (might take a group effort and some building from you. also, do you have any deadlines? it might take a while to get a working end result :-/