OK, I have been tweaking my little powered USB box. Added a red LED which flashes when the battery voltage gets low and a green LED to indicate it is charging. Can't add any more the bloody box is now full!

I made up an extension USB cable from the hacked remains of the Nokia one and a USB female socket. This allows me to plug things into my little box of tricks and measure how much current is being drawn. Here is what I found:

My USB stowaway keyboard draws bugger all. Not surprising since it had no LEDs and is designed to work with portable devices. I measured about 2mA. Still can't get it to work right though as every keypress just repeats. I think that's an OS thing not the KB which works fine on my real PCs.

My 128mB USB pendrive is more interesting. If you have the USB cable uplugged from the 770 and plug it in (i.e. into the box of tricks by itself) it draws a huge 71mA.

With the cable plugged into the 770 (in normal USB mode) if you plug the pendrive in it draws 37mA.

When you then enable host mode to detect the pendrive the current goes up to 41mA after a few seconds and the drive is detected. At this point the little LED on the drive comes on.

Mounting the pendrive the current jumps to 52mA momentarily. This seems to happen when the drive is being read. With the drive mounted I can the access it via the file manager. Playing an MP3 off it will cause the current to jump from 41mA to 52mA every few seconds as it is reading from the drive. I didn't seem to be able to copy anything to the pen drive though.

I don't really have anything else to try plugging into it that I know will work. I can't imagine ever really wanting to use the pen drive on it unless I wanted to use it as a way of transferring things across. I really wish my keyboard would work though.

Simon