Not sure if this is a long term fix, but we’ll see. So far I have only walked with it. I’ll report back when I run with it.
Anyway, I looked it up online and I couldn’t find where anyone else had done this. My sensor was dead, so I used a razor blade to cut the case apart. The battery it uses is a pretty standard CR2032 3 volt watch battery. All I did was unsolder the connections from the old battery, remove the piezoelectric accelerometer from the top of the battery and then solder the wires to the new battery and glue the acceleromete to the top of the battery. I haven’t glued the case back together yet and my Ipod still reports that the sensor has a low battery, so we’ll see how long it lasts.
Here’s some links I found to what the guts of the sensor looks like:
How Stuff Works
Sparkfun Electronics