Nds Measure
Tim (almost) fried his DS, here’s how he figured out the current consumption for all sorts of components and more –

So I was busy homebrewing on my NDS, even bought myself a DSerial board to use it as an ultraportable serial/debug console. I had a few ideas for the much faster, native parallel interface too, so when we were sending out boards at work, I threw my own “DParallel” onto the layout. The boards came back, and we had to cut them apart…note to self: DO NOT let your machinist saw apart your boards on a huge gritty band saw. As is semi-common practice (and just like on the DSerial) I laid out a big VDD (main system power) plane on the bottom of the board and a big GND plane on top. Before inserting the board, I peered down the sides of the card slot to be sure they weren’t metal that would short against the sides of the board, and even performed some quick “due diligence” checks with an ohmmeter to be sure I didn’t do anything stupid (such as somehow shorting VDD and GND together) that would result in frying my DS.

Nintendo DS current consumption – Link.