Hidden Reed Switches For DIY Home Security

01-Before

[Rhys] wanted to secure his home against burglars, but didn’t want to go the normal route of using those bulky plastic magnet and reed switch deals. So he sourced some glass reed switches and made his own completely hidden security system.

By using small glass reed switches [Rhys] was able to mount them flush to the wood paneling just above the window frames. To do this he drilled and then chiseled two slots for the reed switches to go in, with the wires routed into the house. A bit of bondo or drywall filler and some paint later and they are completely invisible! To finish it off he glued small neodymium magnets to the top of the window frame which close the switches. It’s a very clean build and quite inexpensive to do — the possibilities for wiring up your entire home like this are quite tempting!

He’s got the switches installed already… why not couple it all to a complete home security setup? We shared a project last year that does just that!

36 thoughts on “Hidden Reed Switches For DIY Home Security

  1. I’m a communications and security tech, we’ve done this a few times for people where money is no object… Labor is expensive.

    While it looks a lot better, seeing security on everything is a much better deterrent than the security system itself.

      1. Whether or not having a clear security presence means you have something worth protecting (compared to any other home owner) is up for debate. But regardless, the ‘average’ burglar scouting an area is more likely to try steal from one of the 15 houses without an alarm rather than the house that clearly does have one.

        1. Exactly, that is why I broadcast it. ADT stickers in the windows, yard signs, and cameras outside. You want your security to have a big blinking light on it screaming, “I WILL MAKE NOISE IF YOU TOUCH ME” so they rob the neighbors instead.

      2. “a high security presence shows you’ve got something worth protecting.”

        Is it worth taking the risk of getting caught over an unknown quality?

        Usually people are dumb, and will just move to the next house… without security

      3. Plus, there’s the fact that if a burglar decides to go in through the window, they will break the window instead of opening it, because to open a window they’d need to break it anyways so it’s quicker to smash it in completely.

          1. That gives me an idea: you could combine both by painting a thin ribbon of ITO or some see-through conductive polymer across the glass. A strip of foil for capacitive coupling in the window frame would test both the breaking of glass and whether the frame is open at the same time.

          2. @fartface
            Yeah, I agree, it’s totally pointless to have sensors for windows opening but not break sensors.

            That said, most houses I’ve seen with security systems have something wrong with either the house or the system such that the whole exercise is pointless. Either the control panel is exposed and visible right next to the door so you can rip the fucker off before it gets past “please input code” or there’s a trellis leading up to a window without a sensor, or something else like that.

          3. @Dax. That is exactly how first gen glass sensors worked. In some areas of the world they are still very popular sometimes due to age and sometimes due to custom. Initially they were a common site in middle-eastern jewelery stores. They never really spread very far in western countries.

    1. Way more effective to have security visible.

      Face it, all this security cameras and sensors are not to catch the burglar but to keep them away. If the burglar really wants to get into your house he’s going to do it.

      Seeing security in the house just makes the burglar think if it’s worth the effort to get into your house.

  2. i did the same but the reed switches are very fragile and after a few slammed doors due to wind they shattered, changed over to industrial encapsulated units, still hidden but much more robust, i also fitted a magnet to the dead bolt and a reed switch in the jamb that way the system can tell if the door is locked perfect for those of us with OCD

  3. Along with surface mount you can readily buy (at least in the UK) for very little money flush mount switches. Where you drill a hole and insert them.
    For a little more money you can also buy minature versions. Which come with the terminals, EOL resistors and so on.

    For simple two terminal ones, buy a pack of 10 shipped from China for $5

    A hack for hack’s sake ??

          1. Indeed, both the reed switch and the magnet are available in the form of flush-mount plastic “plugs” that fit a (usually) 1/4 inch hole. I picked up a large box of Honeywell flush-mount units very cheaply from an online source, though we used them because they are less likely to be damaged/tampered with. Still have the ADT stickers in the windows.

          2. Yep. Often used on interior doors in office complexes. They are all wood anyway and you don’t want the other people that have access to the complex to enter your business suite without being noticed.

        1. Actually it was really hard to take the photo because of how close the top of the sash is the eve. Hard enough to take a photo let alone get tools up there to make a hole to insert the magnet. Would have had to take the sash off.

  4. Fantastic hidden switch!…. Lets break the window to go in…

    The idea is good but if you could add a way to detect if the window is broken then better. The switch is only good if you leave the window unlock else the burglar will just pick the best window which he can break and go in.

    1. Actually we had a burglary through that window. It’s the only easy one to access from a height perspective. No they wont break the glass and go through that small opening. Why? because it’s noisy to break and sharp to get through. No, much easier to use a pry bar – no wooden joinery can stand up to that amount of leverage and then you have a opening big enough to get in (and out of with stuff because the house is dead bolted). Much quicker/quieter with a pry bar. I would say it probably took under 10 seconds. And even if they do break the glass they will still reach in and open the the window rather than climb through the broken glass.

      This break-in prompted me to install the alarm. Had it been in place at the time they would have tripped the reed switches as soon as they started to pry the window and with a total of 6 sirens/screamers inside and outside of the house they probably would have run off before they entered.

  5. Great, now you know when people open your windows when you forget to lock them(I guess). With that type of window and the restricted open, they’re going to break the glass and climb through, not open it and trip the reed switch. You’d be better off with glass break detectors inside the room or laminated windows.

  6. Actually we had a burglary through that window. It’s the only easy one to access from a height perspective. No they wont break the glass and go through that small opening. Why? because it’s noisy to break and sharp to get through. No, much easier to use a pry bar – no wooden joinery can stand up to that amount of leverage and then you have a opening big enough to get in (and out of with stuff because the house is dead bolted). Much quicker/quieter with a pry bar. I would say it probably took under 10 seconds. And even if they do break the glass they will still reach in and open the the window rather than climb through the broken glass.

    This break-in prompted me to install the alarm. Had it been in place at the time they would have tripped the reed switches as soon as they started to pry the window and with a total of 6 sirens/screamers inside and outside of the house they probably would have run off before they entered.

    1. So the next time they come, they take a roll of contact paper, glue it to the glass and break it clean off. Then put a car floor mat in the hole and step through, wiser from the fact that they know where your alarm switch is.

  7. Um for you guys that keep screaming “they’ll just break the glass!” – If you have ever intsalled a security system and are half way smart about it – including a glass breakage sensor in the package is the norm. Its a small device located somewhere in the middle of the house that detects the sound of breaking glass… They work quite well. Also, motion detectors are pretty standard as well. They are activated by the “away” setting on the alarm so that when the home owner is away, the alarm system will detect movement inside the home and set off the alarm. And yes, you WANT to advertise that that you have a home alarm, any crook that is smarter than a stump will stroll right on by the house with ADT 99.99999% of the time. The unknown payoff is simply not worth the effort of trying to defeat an alarm system. Stop watching movies and TV…
    Also, a lot of alrm systems only have the main entry doors and a window or two secured with actual switches, and hidden/flush mounts are all the rage. Why? Because crooks don’t know which window is alarmed and which isn’t, its a crap shoot and the odds are always in favor of the house. Plus if you did get past a window or door, our friend the motion detector is going to nab you anyway. Again, if you think any criminal is going to go through the trouble of trying to defeat something like that for an unknown payoff, you watch too much TV.

  8. Can reed relays become magnetized CLOSED – so that if the window is opened, the relay stays closed and doesn’t activate the alarm system?

    Seems possible that the magnetic field that can close a reed relay can permanently magnetize it CLOSED – over a period of time.

    1. No, they don’t get permanently closed due to magnetic fields. You also can’t defeat them by trying to hang a magnet on the outside of the frame over the reed switch. Unless you get the magnet in exactly the right spot the first time, the fields of your magnet and the one in the window sash will cancel each other out and trip the reed switch.

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