I was looking at it and noticing the crud was silver, and then realized that the connector was tinned!

@ xander, 3.3/5v is quite easy to provide, I use 4xAA/AAA NiMH cells for 5v (~4.8v) and 2 Lithium AAA for 3.3volts. It is pretty simple to get ahold of 2 and 4 cell battery holders for AA and AAA sizes, with a switch no less.

For more power you could use 4 cells from a NiMH RC stick pack (usually rated 2500-3200mah compared to 2000-2600 for AA NiMH).

I prefer not to use a power regulator most of the time because of cost and conversion efficiency issues. And why use one when simple battery packs from 700mah to 3200mah are available for a reasonable price?

I agree that it isn’t so simple when you are using a different voltage, but it isn’t necessary to use a 9v battery and a voltage regulator when a plain AA/AAA pack will work just fine.

If I need a voltage regulator I can raid the bin at the local second-hand shop for a wall-wart or a cigarette-lighter converter that supplies the voltage I need. The cigarette-lighter models generally use a simple circuit with rated for use on a 7.2 volt – 16 volt battery, so you are all set for under $2.

Also, no power regulator on board, so you’ll have to provide your own if you don’t want to power this from the USB or some other 5V or 3.3V source.

Can we get a quick link on the right for the arduino articles?