Philmore N.O./N.C. Magnetic Reed Switch, SPDT : 30-10072 (1)

I'm always forgetting to close my garage door. I can't see it from any of my windows so checking it involves a trip outside. After inadvertently leaving it open overnight, I decided to do something about the problem. I wanted a magnetic switch for the garage door to control a [email protected] light inside my house so that at a glance I would know if my garage door was open.Most of the magnetic switches I looked at on amazon aren't rated for more than a few watts, with reports of failure or fused/stuck switches after a few weeks or months when used with 12VDC at even .5 amps. The only way around this would be to wire up a 12V relay, which I didn't want to do since that adds another point of failure (and also because I'm cheap and lazy.) This switch is rated at 8 watts. (listing says 10, but the markings say otherwise... "MAX [email protected] amps". 80V*.1A = 8W) still well above comparable switches at the same price.I ran the cables and installed the switch this morning. So far everything is working perfectly. I'll come back from time to time and let you know how it's doing.EDIT: 8/29/2015 - Exactly one month in and it's still working flawlessly. I open/close my garage three times a day on average, so that's around 100 open/close cycles so far without issue.EDIT: 10/9/2016 - Over a year later and it still works exactly as it did the day I installed it. Zero problems whatsoever.

As others have said, the switch has good range: the magnet only needs to be about 1/2" - 3/4" away to work -- great for use on a door switch, since it's not always possible to get the two pieces on top of each other. It comes with foam tape, but can also be mounted with screws.One thing to be aware of: the marking label on the switch (N.O./N.C.) represents the way the switch acts WHEN THE MAGNET IS IN PLACE. That's opposite of most switch conventions, which usually show the 'rest' state of the switch.

The magnetic switch is a replacement of a garage door design that I came up with 12 years ago. It all started in the fall of the year, dry fallen leaves blowing around in the street. On my garage door there are electrical sensors about 4 inches from the floor to stop the door from closing in case something is between these sensors, like a child or whatever, and the door immediately stops. In my case I closed the door late in the evening and leaves blowing into the garage set the sensors off. You guess it. The door was up all night. I then installed a magnetic switch to illustrate the door was shut with 2 pin lights in the 12-volt circuitry mounted in the frame of the ceiling light in the short hallway on the house side of the garage man door; red and green showing door open and door closed. We can see these lights from our great room. That problem solved. About 2 years later, the neighbor across the street backed his car into his garage door thinking it was all the way up, it wasn’t; a mechanical failure stopped the door about two feet from being entirely open. His cost to replace the door was $1,250.00. I then installed a second magnetic switch on my door with a quarter size green light mounted on the front wall of the garage, showing the door was completely up. That switch failed after 10 years of use. This is the replacement I just bought. The entire design to me was, good insurance, good security and a piece of mind for a few dollars. Robt.

I used this reed switch in combination with the Belkin WeMo Maker  Belkin WeMo Maker Wireless  to automate detection of Open/Close on my front door. I connected the "C" and "NO" contacts of the Philmore reed switch (at the front door) to the "S" and "-" sensor contacts of the WeMo Maker (on the other side of a wall in the laundry room), and I get a WeMo "trigger" sent to my iPhone whenever the front door is either opened or closed. The air gap between my door and its doorframe is about 1/2-inch, and the typical 3/4-inch activation distance of this Philmore reed switch worked reliably. In contrast, I had reliability problems with the weaker model Magnetic Switch by Directed Electronics  Magnetic Switch  which activates at between 3/8-inch and 1/2-inch.

These did no better than the much less costly version from China. They cannot handle any more current than the less expensive ones. I then opened both types, and the Philmore was more neatly assembled, but the function is the important feature and I was not impressed.

Very happy with the switch both for learning and for practical use. I created a home alarm, with a 120v to 12v converter, a toggle switch to turn it on/off, this reed switch for the door and a 12v bell for the alarm.I did not understand the Normally Closed (NC) v Normally Open (NO), so this switch can do either which is great for learning and use.Normally closed does not mean the 2 pieces of reed are touching - it means the circuit is closed. A reed switch does not pass electricity from one piece of the reed switch to the other. One side is just a magnet that breaks the circuit on the other piece of reed switch breaking the circuit.

What I like about these is that they are very sensitive----and reliable. They can be aligned differently to adjust the distance when they will activate and once positioned at the desired distance they are very accurate to activate at that distance every time. I use them at about 1/4 inch spacing but they can be arranged more in line with each other to activate at a greater distance----probably out to about an inch spacing. Also, If more distance is required one might stick a small earth magnet on the back of the magnetic side and extend and further adjust that distance.

This switch would close (make contact) when the magnet was next to it but, in the circuit, would not open (break contact) when the magnet was removed. I will be looking for another solution.