Magnetic Door Switch Set

This is the Magnetic Door Switch Set, a small reed switch assembly specifically designed to alert you when doors, drawers, or any other aperture opens. These types of switches are primarily used in home security systems. One half of the assembly set on a window or door frame and the other attached to the window or door itself. When the switch set is separated from each other the contact is broken and triggers an alarm.

When each magnet piece comes within 20mm of each other they complete the circuit with the internal reed switches. Each Magnetic Door Switch set can accept a max voltage of up to 100V at 500mA. Additionally each set is housed in durable ABS plastic and, with the included screws, can easily mount to most surfaces.

  • 1x Magnetic Door Switch Set
  • 4x Phillips Mounting Screw
  • Max Voltage: ≤100VDC
  • Max Current: ≤500mA
  • Max Rating: ≤10W
  • Gap: 20±5mm
  • Contact Mode: NO
  • 34 × 41 × 6.5 mm

Magnetic Door Switch Set Product Help and Resources

Reed Switch Hookup Guide

May 5, 2016

Magnetically-actuated reed switches are the perfect component for non-contact proximity sensors. This tutorial provides a quick overview and example hook up.

Switch Basics

May 7, 2013

A tutorial on electronics' most overlooked and underappreciated component: the switch! Here we explain the difference between momentary and maintained switches and what all those acronyms (NO, NC, SPDT, SPST, ...) stand for.

SparkFun Inventor's Kit for Photon Experiment Guide

September 3, 2015

Dive into the world of the Internet of Things with the SparkFun Inventor's Kit for Photon.

Blynk Board Project Guide

March 25, 2016

A series of Blynk projects you can set up on the Blynk Board without ever re-programming it.

N.O. Vs N.C.?

This switch is normally open in the sense that with no magnet present, the contacts are open. When a magnet is nearby, the contacts close.


Core Skill: DIY

Whether it's for assembling a kit, hacking an enclosure, or creating your own parts; the DIY skill is all about knowing how to use tools and the techniques associated with them.

1 DIY

Skill Level: Noob - Basic assembly is required. You may need to provide your own basic tools like a screwdriver, hammer or scissors. Power tools or custom parts are not required. Instructions will be included and easy to follow. Sewing may be required, but only with included patterns.
See all skill levels


Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

2 Electrical Prototyping

Skill Level: Rookie - You may be required to know a bit more about the component, such as orientation, or how to hook it up, in addition to power requirements. You will need to understand polarized components.
See all skill levels


Customer Comments

  • Commanded 5 for a closet application because they are advertised as NO (Normally Open). I wanted to power a LED stipe when the door opens. I assumed that was Normally Open with the magnet beside ! But I was wrong. This switch is closed when magnet is beside it. Sounds more like NC to me !

    • In the electronics world NO means that a device in a non-activated (resting) mode is Normally Open. When the device is activated, in this case when the Magnet and the Reed Switch comes in contact, that normally open switch closes.

      What you are looking for is a NC switch, that stays open as long as the door is closed, and once the door opens and the switch goes back to it’s rest position of “Normally Closed” the lights activate.

  • Are these polarized?

  • Does this require any resistors being hooked powered to an arduino 5v?

  • Strange way to word things “Each Magnetic Door Switch set can accept a max voltage of up to 100V at 500mA”

    I guess maybe I’m just nitpicking but it’s not really “at 500mA” but rather “up to 100V, and up to 500mA”

    Oh, as I made this sentence I realized it’s not particularly easy to state “Max Voltage 100V. Max current 500mA” in a comfortable sentence. But the distinction between these being two different ratings that operate independently, is what I was getting at.

    Also, 100V DC? That’s pretty high- cool.

  • It would be nice to clarify if the NO contact mode is with the magnets influence present or not??

  • So it appears that this is a “normally open” switch. Anyone happen to have a link to the data sheet for this switch? I need to know the temperature range this switch can operate at. A garage in Phoenix can get pretty hot during the summer. Don’t want it to melt.

  • just a few days after I ordered the inferior reed switches :( :P

  • Regarding the contact, I see NO/NC. Is it NO or NC? I need a contact that close when I open the door for a different application than an alarm system.

Customer Reviews

No reviews yet.