Has anyone had any success hooking up some nichrome wire to an Arduino? I want to get the wire up to boiling point (212F) using just the Arduino power if possible, but I could use a transistor to get higher voltage from an external source.
I want to get the wire up to boiling point (212F) using just the Arduino power if possible
Let's do a little math: 5V and 40mA max current from an ATmega pin, so max power is:
5V x 0.04A = 0.2W
I think it's gonna take a while to boil water with 2 tenths of a watt (but I guess that depends on how much water you want to boil 
).
but I could use a transistor to get higher voltage from an external source.
I think that's pretty much going to be the minimum requirement. IMO, you're more likely to need to use a transistor to turn on a relay that applies power to a hot plate or some other AC heating element.
-j
The reprap project has a heating element in the extruder controlled by an arduino, see how they do it