My internal bluetooth is now working properly. Here are a few details of how I got it working. These instructions could be equally applied to adding an internal USB flash drive. Given the amount of space available, I may add a hub, a flash drive and a bluetooth adapter. I've had a quick look and they will all fit quite easily. This is a job for next week.
As you all know, the miniPCIe slot has a USB bus available on it. It also has 3V and ground connections. USB devices expect a 5V supply but this is normally not necessary - the devices work off 3V and regulate the 5V down internally.
First thing to note - do not use the 3V available on pin 52 of the miniPCIe connector. This will make the eeePC try to boot from a flash drive connected to it. Take 3V from somewhere else on the PCB instead. (see red arrow pointing to unused pad in photo).
To modify my USB bluetooth / flash devices to work off 3v was easy. In the case of my bluetooth adapter (which was extremely cheap!) the manufacturer used two diodes in series to drop the 5V to around 3V. I simply attached my 3V supply to the cathode of the second diode. In the case of the flash drive a 3 terminal linear regulator in SOT-23 package was used. I simply bypassed it.
The photo shows where I connected the wires in to - the USB+, USB- and ground connections go to the miniPCIe connector. The 3V supply comes from an unused SMD pad. This 3V supply is off when the device suspends.
Bluetooth range isn't great with the adapter where it is behind a metal lined panel, but is fine for my uses.
If you have any questions feel free to ask.
I've managed to add an internal USB device without loosing any of the external ports or having cables hanging out.
I won't bother with any form of disclaimer except for to say that YMMV and if you break your new toy, it's not my fault!
The blue bit in the photo is a piece of card to which I have stuck the bluetooth PCB.
Edited by tristand, 21 November 2007 - 11:19 PM.