SparkFun Simple Sketches - Magnetic Reed Switch

This is a small device called a reed switch. When the device is exposed to a magnetic field, the two ferrous materials inside the switch pull together and the switch closes. When the magnetic field is removed, the reeds separate and the switch opens. This makes for a great non-contact switch. This switch can carry up to 1.2A.

[MatthewPotter]

To anybody wanting to add magnetic reed switches to their project… buy about 3 to each 1 you need. They work great but the glass is fragile and can break VERY easily, especially while your bending the leads to both breadboards and solder boards.

[wiatroda]

is Arduino sketch for it available?? :p