A Reed Switch Module is a magnetic sensor that is normally open and get closed when exposed to a magnetic field. In our example turn off the built-in LED on pin 13 if the sensor is closed. For this you need to keep a magnet near the sensor. The module includes a 10 K Ohm resistor, so no additional parts needed.

Features:

• Open reed switch.
• Working voltage: 3.3V~12V.
• More than 15mA.
• Output format: digit switch output (0 and 1).
• Dimensions: 1.57 in x 0.55 in x 0.28 in (4.0 cm x 1.4 cm x 0.7 cm).
• 0.18 oz (5 g).
• Using a wide voltage LM393 comparator.
• Fixed bolt hole for easy installation.
• Comparator output, clean signal, great waveform, and strong driving ability.