I won't go into medical detail on all the wiring (the pinout is in the slideshow at the bottom) but here's the general idea.
- Identify the interface and pins on the internal USB port.
- Find a USB hub that will physically fit into the eo.
- Find a fast flash drive that will also fit.
- Cut and wire the internal USB port to talk to the hub.
- Wire a port on the hub to manage the WiFi/Bluetooth module.
- Get it all to actually fit.
The first step was the choice of hub. I chose the one above because it was very small and because the upstream port was already a cable so I would not have to solder another one on.
Initial fit looked good and it LOOKED like it was about the height of the heat sink, meaning the lid would close. The Flash drive was an easy choice: The Sony Micro Vault Tiny 2GB was both cheap and fast enough to use for ReadyBoost, even through a hub.
I was pleasantly surprised to see the PCB was cut away at an angle on the inside as well. The four wires that were previously connected to the USB cable were very disappointing though.
Each one fell off at different times during the project and had to be re-soldered back to the PCB. I removed the metal shell and plastic guide from one of the ports and soldered on some leads.
Heat shrink tube was especially important to this project. Soldering wires together isn't enough... a little short in the UMPC could kill it. Remember to slip the tube over the wire before soldering.
The cable above was the most worrisome. It was small, of unknown pin-out, and if I destroyed it I would lose WiFi and Bluetooth on my UMPC making it useless to me. I Googled the part number and found the engineering manual for it including the pin-out, but had no indication of what was pin 1. A couple minutes with the multimeter fixed that.
Wiring was pretty standard, but a total of 20 new solder points (plus re-soldering the original USB hub leads) was rather time consuming.
As you can see above, problems arose when I tried to close it.
First, there were too many protrusions in the bottom. I cut out most of the stylus stand, an extra riser, and then eventually all of the air vents to get it to fit.
Post Dremel work, but the lid STILL didn't fit. Why? I placed the hub where it belonged, flipped it over, and removed the back plate. The thing was balancing on the LED.
Of all things, the little green LED was keeping the darn thing open. I had two choices: shave off more plastic from the back of the eo or remove the LED. I went for a third option.
I drilled a hole in the back of the eo for the LED. I added four more holes between the grips for more ventilation while I was at it.
Here it is all wired up and with some tape holding it down before I stuck it in with better mounting tape. EVERY step of wiring should be tested along the way and re-wired if it did not work right. The wires were run to avoid mounting holes too.
After one more hardware test, investigation for stability and shorts, and maybe a few more pictures - Finally closed! It works, but does it ReadyBoost?
Why yes. Yes it does. And that's all for now. I am looking for other devices with small enough dongles to take over the other two USB ports. Maybe more Flash drives. Maybe an RF remote control. We'll see. Here's a slideshow linking to a bigger gallery of high-res images.
*edit* Users are asking me if the addition of extra hardware pulls battery life or if the addition of a ReadyBoost drive INCREASES battery life. I have yet to run those tests, but stay tuned.