I'm looking for reasonably priced and reasonably easy to implement ways to measure voltages with a computer. To be more specific:-
The computer will either be the existing eeePc running Ubuntu (but no GUI) or a raspberry pi.
I need to monitor at least four and preferably eight or so voltages, some of these are 12 volts (i.e. lead acid batteries) and others are current transducers giving an output around 2.5 volts with a +-0.5 volts swing.
I don't need *incredible* accuracy but something around 2% or better is necessary for it to be useful in monitoring battery charge state.
I want it to be cheap!
Sample rate can be slow, once an hour would be fine.
I have a 1-wire interface implemented which currently measures temperatures but I can't find any quick/easy way to add voltage measurement to 1-wire. It can be done but gets 'messy' and 1-wire seems to be a disappearing technology.
I've looked for volts->USB interfaces but can't find much, if someone knows of anything I'd be pleased to hear about it.
Any ideas for cheap hardware to do this (I am happy to solder things etc.) would be very welcome.