Intro

I while back an email was circulating around pointing to a site where a guy called "Japala" had posted photos of his mouse mod which he called the "Cryo Mouse". If you're looking for the original Cryo Mouse, please check out Project Cryo on his site [MetkuMods].

Photos

Photos detailing the progress of the construction of my Cryo Mouse can be found here.

Please don't hot-link any of the photos. I don't have the bandwidth to support that

Tools

I got to have fun - it's my first time using the volt meter, soldering iron, Dremel, hot glue gun, sandpaper, spiffy industrial lights, the stove, and of course my trusty Swiss Tool, all on the same project.

Parts

• mouse: "IntelliMouse® Optical USB"
• blue LED, 5V, 20mA, 1000mcd. ($5 at Radio Shack)
• small sheet of 1mm acrylic. ($3 at Home Depot)
• Lego man, legs removed.
• Tin foil.
• two spare wires from my spare parts box.

Prices in $CDN, for the curious. (Yes, I know $5 is a lot for an LED - it was convenient.)

Please read my disclaimer above.

The Process

• I started by taking apart the mouse. (for the uninitiated, the screws are under the pads)
• Next I drew the outline of where I wanted to cut on the inside of my mouse's shell.
• The front and back circuit boards snapped out easily.
• I unplugged the USB cable from the mouse and started poking with my volt meter.
• I found a 5V (actually 4.88V) difference between the red and black, and between the red and green wires. So I un-cleverly poked the LED into the red and green holes. The computer beeped ("Unrecognized USB device" or "Error communicating with USB device"... something like that.) Oops. The red and black wires gave me what I was after: my led glowed a nice bright blue.
• I then looked up "USB pins" on the 'net, which I really should have done first, and confirmed that the red was +5V and the black was ground. The green, it turns out, is USB data. Go figure.
• Conveniently my LED was 5V as was my USB power, so no resistor was required. I read about LEDs at a bunch of websites to figure that out. So I soldered my wires to the incoming power from the USB cable.
• I then proceeded to cut out the marked area, using my Dremel. At this step I really should have done the plastic molding first. Why? Because if you try to mold hot plastic around a shape with a big hole in it you get an indent where the plastic dips into the hole.
• Next I hot-glued tin foil to create the background, being careful to keep it away from anything electrical.
• I noticed the rear circuit board was mostly empty, just containing contacts for the red rear LED. (1.2V I think it was - not enough to chain up the blue LED, which is why I wired from the USB directly.) So I took advantage of the extra space and glued my LED to this board, leaving room to solder on my wires from the USB.
• I then put the thing back together to see what it looked liked (without acrylic). It was pretty cool.
• The next day I picked up some acrylic from Home Depot. (they call it "plexi glass") I ended up buying a 1mm thick sheet, about 9x14", but I'd have preferred slightly thicker because the mouse's plastic was 2-3mm, which would have helped with the fitting.
• I read about a lot of problems people online had with heating their acrylic in order to bend it. Some people suggested using lighters, or boiling water. I found about 10 seconds over my stove did the trick. I think 11 seconds would have had the thing dripping onto the stove's open flame - not clever in retrospect, but very useful.
• I quickly pressed the hot plastic over the mouse's back, using an oven mitt to protect my hand, and tin foil to protect the mouse. It hardened almost instantly.
• A bit more Dremel work (and some sanding) and I had a small square of plastic, the correct size, shape, and curve for the hole.
• I used epoxy to glue it on, because it dries transparently. Test your glue first - some (like fumes from super glue, I'm told) will etch the acrylic.
• In the original Project Cryo, Japala had sanded his acrylic to give it a frosted look. I elected not to for mine, but I probably would if I did the mod again.
• I had to redo the tin foil after putting in the window.
• Hot glue was used to attach the Lego guy's hands to the mouse, to keep him from rattling around.
• Reattaching the shell, and I'm done.

Things I learned

• Don't bother unscrewing the middle circuit board like I did - it didn't gain me anything, and was a nuisance to put back in.
• After each step I'd plug in the mouse to make sure I hadn't broken the thing.
• Look up your electrical schematics before poking around randomly.
• Understand what you're doing with your circuit - I read a lot about wiring LEDs while doing this mod. (Mostly because it was my first mod.)
• Form your acrylic before cutting out the window hole. I had to use a second mouse as a mold, since I did my cutting first.
• Just because something looks soldered, doesn't make it so.
• This mouse relies on precision placement of the circuit board in order for the mouse wheel button to work properly. My soldered-on wires were pushing up on the board, just slightly, but that was enough to put the wheel button out of tolerance. I eventually got it to fit.
• Plastic doesn't as much get cut by the Dremel, as it does melt out of the way.
• Total time was longer than expected (4-6 hours?), mostly because some steps took much more time that I would have guessed. (Cutting plastic took a while, because I was being careful to avoid damaging anything, etc...) Research time was significant too - as I said, my first mod.

Conclusion

I had a lot of fun doing this mod. I really like the final look.

Check out the photos.