Illuminated Mask
Contributors:
Gella
Gella 
Installing Your Battery and Testing
Insert the coin cell battery into the battery holder with the positive, labeled as (+), side facing up. Slide the switch to ON to see the LEDs light up. Remove the battery, and then continue to the Finishing Touches section.
How to place a battery in a LilyPad Battery Holder.
Troubleshooting
With any electronics project, there are times you will have to troubleshoot if your circuit isn't working. If your circuit isn't lighting up, try a new battery or check that your project is switched on. Check your sewing for any loose threads or ends that may be touching other parts of your circuit and causing a short circuit. Learn more about troubleshooting your project in the LilyPad Basics: E-Sewing tutorial.