For makeing this led indicator for your wallet you will need one CR2016 lithium battery,one small magnet and led diode.
How it works,when there is no money in wallet the led is on and mean to put cash in wallet,when cash is inside wallet the led is off,circuit is very simple but great :)
Visit my blog for more projects:http://macoprojects.blogspot.com
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.