So I wanted to run with my Nike+iPod kit today and lo and behold after a year of it sitting in my shoe it was dead. I went to the shops to buy a new one and it was R250 (about $34) for the sensor alone. So I decided to open the thing up myself, after doing so I found that it uses the same sort of battery that's inside my apple remote. So the problem presented a mod project... I cut up the sensor and applied a bit of skill and luck to fit in some sort of user replaceable battery. I soldered together some contacts and tried to keep all the electronics including the piezo-electric sensor under the covered part. Unfortunately every time I put a battery in it bends the piezo sensor a little bit (I dunno if this affects the working of this sensor?). So here's the pics: EDIT: I really need to get better tools for the next mod. Any donations of tools would be welcome. I need a nice little hacksaw, a wire cutter, some helping hands for soldering, a blade... I have another sensor that I'll try do nicely with proper tools. The metal I used for the contacts is from a headphone jack I wasn't using.