{"id":17307,"date":"2016-02-03T11:18:35","date_gmt":"2016-02-03T11:18:35","guid":{"rendered":"http:\/\/randomnerdtutorials.com\/?p=17307"},"modified":"2023-04-23T11:10:55","modified_gmt":"2023-04-23T11:10:55","slug":"monitor-your-door-using-magnetic-reed-switch-and-arduino","status":"publish","type":"post","link":"https:\/\/randomnerdtutorials.com\/monitor-your-door-using-magnetic-reed-switch-and-arduino\/","title":{"rendered":"Monitor Your Door Using Magnetic Reed Switch and Arduino"},"content":{"rendered":"

This tutorial demonstrates how to use a magnetic reed switch. I’ll do a quick overview on how it works and show a project example using an Arduino.<\/p>\n

<\/p>\n

Description<\/h2>\n

A magnetic contact switch is basically a reed switch encased in a plastic shell so that you can easily apply them in a door, a window or a drawer to detect if the door is open or closed.<\/p>\n

The switch that we are going to use has two parts: the switch itself, that usually comes opened, and the magnet. When you buy this switch, it also comes with 4 screws, so that you can attach it to your door.<\/p>\n

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How does it work?<\/h2>\n

It\u2019s very very simple.<\/p>\n

The electrical circuit is closed when a magnet is near the switch (less than 13 mm (0.5\u2019\u2019) away). When the magnet is far away from the switch, the circuit is open. See the figure below.<\/p>\n

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Where to buy?<\/h2>\n

These switches are very cheap. You can buy them on ebay here<\/a>.<\/p>\n

Project Example<\/h2>\n

In this example, we will turn on a red LED if your door is open and a green LED if your door is closed.<\/p>\n

You’ll need the following components:<\/p>\n