Good news everyone :)
I bought a Nike sensor a long time ago, with the promise that I would start running/walking more often and be able to track my progress. Turns out I didn't use it and when I finally decide to give it a try the sensor was dead already. :(
Not willing to buy a new one ($20.00) value I decide to search for options.
This instructables offers my take on replacing the battery of the Nike sensor.
Disclaimer: few of the pictures are not mine and I will provider the proper credit.
Please don't forget to rate this instructables if you like it. Thank you
Step 1: Disassemble the Sensor
The way I did was using a X-acto knife to open the sensor, be careful not to cut yourself, this is a task that takes time and patience. Since I didnt take pictures during this part of the process I am using someone's else pictures.