DIY web site Instructables demonstrates how to replace a dead battery in a Nike+ iPod receiver in just a few minutes for under $5. When I highlighted the best tech tools to get in shape, I sang the praises of the Nike+ iPod sport kit. But Apple says a whole new sensor is required when the battery dies in the $30 device, so the 10 minutes and $4 battery required for this little DIY seems worth the effort if and when your battery takes the long sleep.