LilyPad Reed Switch Hookup Guide
Contributors:
Dia
Dia 
What is a Reed Switch?
Before we learn how to use the LilyPad Reed Switch, let's learn how reed switches work.
A reed switch is a simple mechanical switch that is activated via a magnet. Two thin pieces of metal inside are nearly, but not quite, touching. When the device is exposed to a magnetic field, the two ferrous materials inside the switch pull together, and the switch closes.
You can learn more about momentary switches over at our Switch Basics tutorial.
From top to bottom: A glass PTH reed switch, an insulated plastic PTH reed switch, and a reed switch designed for doors and windows. If you look closely at the center of the top, glass switch, you can see the metal arms inside.