I hope to use my arduino to control charging some NiMh batteries using a circuit much like Peter Hayles did using a PIC on his website: http://www.angelfire.com/electronic/hayles/charge1.html. Below is a diagram of his circuit (fig 3):
Now my question for all the EE types out there. He uses a transistor to turn the LM317 on or off to fast charge his batteries.... How does he change the current for trickle charging at 4% of the speed of the fast charging? I think you could use a current divider and another transistor, but that may not be the best way.
A little background about myself... I did a few years of EE before changing majors to Mathematics 10 years ago.
I just discovered the arduino and it seems to represent the most interesting and fun part of EE!!