SM-226L-3Q Seco-Larm Overhead Door Mount N.C. Magnetic Contact w/ 3 Wires for N.O./N.C. Applications (One Pack)

This sensor was the perfect choice for sensing when my roll up garage door is completely secured. What I like the most is that this model supports both Normally Closed and Normally Open systems; There are three wires, red/black/green. When the door is closed, there is continuity between Black/Green When the door is open, there is continuity between Black/Red In my application I discarded the red wire and have a raspberry pi send a text notification when the door is opened unexpectedly. The activation range is very good, over two inches. This prevents false alarms when the wind blows against the overheard door and it moves slightly.

This was needed to replace a failed magnet switch which Id bought about a month earlier to make an indicator light for my garage door. I wish Id gone this route the first time. This item is very high quality and was easy to install as it is made for this application.

Switch can not handle the wattage that it says. First time I hooked it up the reed switch welded itself closed.

Good quality unit

I bought this to drive a garage door open warning light in my residence. The sensor is designed to be installed on a garage floor, but I chose to install above my rolling door. This meant that the supplied magnet bracket didnt fit, so I built a custom bracket out of sheet metal. Combined with a power supply and blinking LED, I got just what I wanted for less than $30. There are lots of mechanical reed switches available for far less, but I wanted something more robust so Im not replacing it in a year. Im completely satisfied.

recieved as expected based on description. OEM would have been a better choice.

Perfect switch to be used in a basic DC electronic circuit that detects if the garage door is opened or closed. Provides a visual piece-of-mind that the door is closed,

need a good masonry drill bett

Not much to say, but its made well, and should last years. As far as wiring, black is common, green is normally open, and red is normally closed. Pretty straight forward...... Well worth twenty bucks......

Triggers about 2-3 inches away ! Built really well ! worth it $$