MagicMirror Forum
    • Recent
    • Tags
    • Unsolved
    • Solved
    • MagicMirror² Repository
    • Documentation
    • 3rd-Party-Modules
    • Donate
    • Discord
    • Register
    • Login
    A New Chapter for MagicMirror: The Community Takes the Lead
    Read the statement by Michael Teeuw here.

    PIR sensor behind glass?

    Scheduled Pinned Locked Moved Hardware
    65 Posts 16 Posters 100.6k Views 19 Watching
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • D Offline
      dmcinnes Module Developer
      last edited by

      Another possibility: I ordered a couple of these $2 microwave radar motion detectors to see if they will work behind my glass. Still waiting to receive them though:

      http://m.ebay.com/itm/1pc-5-8GHZ-Microwave-Radar-Sensor-6-9M-Smart-Switch-for-Home-Control-/131864712562?txnId=1245760396003

      More details:
      http://www.cnx-software.com/2016/04/04/tiny-microwave-radar-module-detects-movements-up-to-9-meters-away-for-2/amp/

      yo-lessY 1 Reply Last reply Reply Quote 1
      • yawnsY Offline
        yawns Moderator
        last edited by

        Wow, the microwave approach sounds good. Will this work behind the mirror?

        D 1 Reply Last reply Reply Quote 0
        • yo-lessY Offline
          yo-less Module Developer
          last edited by

          @dmcinnes Thanks for your link, I’m using a radar module in a Pi-independent LED lighting control unit that a friend of mine put together (So I have no clue how his circuits actually work, but they do and that’s great :D), which is why my first impulse was to use a radar motion detector as well.

          I couldn’t find any that operated within the voltage specifications of the PI’s pins. Your link lists a working voltage range of 5.5 - 18 V DC, but the Pi only offers 5 V DC, doesn’t it?

          So are you planning on using an external power source for your module?

          1 Reply Last reply Reply Quote 0
          • D Offline
            dmcinnes Module Developer
            last edited by

            Hmm I’ve seen othe specs that say working voltage is 3.3-20VDC… hopefully that’s more accurate. In any case I’ll try it with the 5V from the PI and go from there.

            yo-lessY KirAsh4K 2 Replies Last reply Reply Quote 0
            • D Offline
              dmcinnes Module Developer @yawns
              last edited by

              @yawns I’ve read that microwave sensors will work behind glass, but I’m not sure if it will work behind the semi-mirrored surfaces we’re using.

              1 Reply Last reply Reply Quote 0
              • yo-lessY Offline
                yo-less Module Developer @dmcinnes
                last edited by

                @dmcinnes It’s great that you’re experimenting with this in any case. Please let us know the outcome once the sensor has arrived.

                1 Reply Last reply Reply Quote 0
                • KirAsh4K Offline
                  KirAsh4 Moderator @dmcinnes
                  last edited by

                  To anyone asking: ‘working voltage’ just means it will work with voltages within that range, so from as low as 3v3 up to 20v.

                  A Life? Cool! Where can I download one of those from?

                  1 Reply Last reply Reply Quote 0
                  • yo-lessY Offline
                    yo-less Module Developer
                    last edited by yo-less

                    Alright, everyone. I said I would start experimenting with the PIR sensor and experiment I did.
                    So first of all we started drilling a hole of diameter 8mm into one side of a piece of wood
                    (we went 5mm deep as this corresponds with the height of the cylindrical sensor):

                    0_1472843356492_sensor2.png

                    This is not all we did, as you can see, we also drilled a hole of diameter 3mm on the other side,
                    but this time we made sure it went all the way through:

                    0_1472844079617_sensor4.png

                    Next, we removed the Fresnel lens from the sensor:
                    0_1472844126023_sensor3.png

                    After that, we put the sensor in the bigger hole which perfectly houses the whole cylinder:
                    0_1472844139302_sensor3.5.png

                    Then we waited to see whether the mirror would turn itself on if we moved past the piece of wood.
                    And, hooray, it did!

                    Emboldened by this discovery, we started all over again, but this time with smaller holes on the other side,
                    so we ended up with this setup:

                    0_1472844320166_sensor1.png

                    Simply ignore the rubber band, it’s there to hold the circuit board in place :)

                    Anyway, here’s the good news: The mirror recognizes somebody walking by if the hole is as small as 2 millimeters in diameter.
                    It did not work with a 1mm hole, but hey, are we living in a perfect world? :D

                    Anyway, this solution is good enough for me, we will drill a 2mm hole in the bottom center area of the mirror frame and hide the sensor behind it.
                    I’m thinking we might even be able to make the hole less apparent by choosing a piece of wood similar to the one above
                    with some nice-looking wood grain and / or knots.

                    1 Reply Last reply Reply Quote 7
                    • cowboysdudeC Offline
                      cowboysdude Module Developer
                      last edited by

                      That is awesome!!! Great job and Thank you for the info!!!

                      1 Reply Last reply Reply Quote 0
                      • D Offline
                        dmcinnes Module Developer
                        last edited by

                        I got the microwave radar modules today!

                        They work great, even behind my mirror, although they are very sensitive. It triggered on even small arm movements and didn’t require line of sight. Works for my needs though, I just want it to turn off the monitor when nobody is around.

                        I haven’t tried powering them with my PI, but they worked fine with an external 5v power supply.

                        yo-lessY 1 Reply Last reply Reply Quote 2
                        • 1
                        • 2
                        • 3
                        • 4
                        • 5
                        • 6
                        • 7
                        • 3 / 7
                        • First post
                          Last post
                        Enjoying MagicMirror? Please consider a donation!
                        MagicMirror created by Michael Teeuw.
                        Forum managed by Sam, technical setup by Karsten.
                        This forum is using NodeBB as its core | Contributors
                        Contact | Privacy Policy