I’ve looked and looked for something off the shelf to power an Arduino in a automotive environment. Closest seems to be hacking up a usb car charger, but I’ve tried that twice and both times it didn’t work (but my project works fine with the usb from my laptop, go figure). Tried dc-dc converters and they didn’t work. I think it’d be nice to have something that would provide clean power to an Arduino and be as simple as hooking up +/- input from the noisy electrical system and have a barrel jack output that is clean. And preferrable something I can screw down in my enclosure. Maybe something like that exists, but I just can’t seem to find it.
There’s not much out there at the moment, as you said, the supply is quite noisy. I’ll keep the idea in mind and post if I hunt something down.
Google “automotive noise filter schematics” or “automotive surge (spike) suppressor schematics” and you’ll find a number of useful circuits. There doesn’t seem to be much off the shelf, but spikes of greater than +/- 100 volts are occasionally observed, and destroy many an experimenter’s circuit. Background info at http://www.digikey.com/Web%20Export/Sup … etwork.pdf
Here are a couple of circuit examples:
http://webpages.charter.net/dawill/tmor … Filter.png (my favorite, that 1.5KE18 diode is a 1500 watt surge suppressor zener, available nearly everywhere and cheap).
Add a surge suppressor zener to this one: http://www.worldwidedx.com/home-brew/31 … ilter.html
With a voltage regulator: http://linuxcar.sone.jp/reg.en.html
There is this on ebay: http://www.ebay.com/itm/40-AMP-IN-LINE- … 0658370283
SPARKFUN: Strong hint for a desperately needed product!