What’s Behind The Door? An IoT Light Switch

We’re not sure who designed [Max Glenister]’s place, but they had some strange ideas about interior door positioning. The door to his office is right next to a corner, yet it opens into the room instead of toward the wall. Well, that issue’s been taken care of. But the architect and the electrician got the last laugh, because now the light switch is blocked by the open door.

Folks, this is the stuff that IoT is made for. [Max] here solved one problem, and another sprang up in its place. What better reason for your maiden voyage into the cloud than a terrible inconvenience? He studied up on IoT servo-controlled light switching, but found that most of the precedent deals with protruding American switches rather than the rockers that light up the UK. [Max] got what he needed, though. Now he controls the light with a simple software slider on his phone. It uses the Blynk platform to send servo rotation commands to a NodeMCU, which moves the servo horn enough to work the switch. It’s simple, non-intrusive, and it doesn’t involve messing with mains electricity.

His plan was to design a new light switch cover with mounting brackets for the board and servo that screws into the existing holes. That worked out pretty well, but the weight of the beefy servo forced [Max] to use a bit of Gorilla tape for support. He’s currently dreaming up ways to make the next version easily detachable.

Got those protruding American switches? [Suyash] shed light on that problem a while back.

33 thoughts on “What’s Behind The Door? An IoT Light Switch

    1. This is how all houses in the UK used to be setup, with doors opening into the room. Our house (1954) is still this way, but a number of our neighbours have had the doors switched to opening against the wall. Of course, this has to be done in conjunction with a rewire to move the switches.

      1. Quite the opposite – it’s very easy to obstruct and prevent exit if the door swings outwards. If it swings inwards, then it’s under your control to remove the obstruction.

        1. In the US public buildings have their doors open outwards. This was put into the code after some high profile mass deaths because crowds of panicking people crushed each other against the door while trying to escape a fire, preventing the door from being opened.

          Homes generally have their door open inward for various reasons, including having the hinges on the inside so a would-be introduce can’t just remove the door, and allowing for a “storm door” that opens outward.

      2. You are interpreting inward and outward correctly but the OP was not. His door is in a corner. When he said “yet it opens into the room” he meant that the hinges are on the side away from the corner. When he said “instead of toward the wall” he meant that the hinges should be on the side of the door nearest the corner.

  1. Nice but why IOT?
    I’m no big tinkerer of my own because I completely lost interest in the hogwash called IOT.
    Use a Raspberry as a dedicated server – or if you have your NAS and connect to a simple website on your local device. Block external facing traffic and you got yourself a deal. So your Lightswitch stays at home where it belongs and does not leave your house.

    Otherwise – Neat project but sadly you can’t see where the USB connects to. I would have loved some shenanigans to connect the device directly to a regulator and to the cables present in the lightswitch so it’s always on – but that could be a future project that could involve a visit to an electrician that knows how to do that stuff safely?

    1. It would still be called IOT (Intranet Of Things).

      Sadly (but for a good reason) in most countries, private people are not allowed to modify the electric wiring of their home, therefore you have to resort to a mechanical solution instead.

      1. Yeah I get that IOT abbreviation – but then again. Why external facing? I’m not a tinfoil-hat wearing person but I don’t need to poke holes in everything that I own at home so I can control it.
        My washing machine has a “remote start” feature which can be enabled ONLY but pressing a hardware-button before putting stuff in so you can’t crack that – but I blocked all ports that this stuff uses nevertheless because why does it have to send data to the manufacturing servers so I MIGHT use their app?
        Again – it’s my home stuff that I can only utilize properly, when I’m at home. Why use it from external?

        Nothing against reading status or checking up on some information – but enabling you to switch that light? Enables everyone on the world to do the same :( (If they really, really want that of course)

        1. Spot on! Unfortunately, due to the way people make money from technology, IOT has become synonymous with the use of third party “man in the middle” services. This results in the concentration of power in their hands, loss of privacy and less safe and reliable systems for little or no value add. There is no technical reason why they are required. The internet should be used just as “plumbing” connecting your smartphone or your other control and monitoring devices to your IOT devices. That is why I am working on “Cloud Free” IOT systems where there is no “man in the middle” and everything is under your control.

      1. Hey thanks for the answer. Yeah I understood that – but this is my main “issue” with installations like these. I would love them but unfortunately, I don’t like the micro-usb cable shenanigans dangling around there. That’s why I said I would like to see that stuff being powered from the wiring in the wall itself so it can be a “self contained unit”. But only IF you have someone who is certified to work on mains power.

  2. I had the same problem and just bought a RF remote light switch. The first one I bought years back consumed about 16W, so I later swapped it for a nicer glass panel model that consumes about 2W (both according to my amp meter). It came with a keyfob (not great to keep around the room), so I took out the PCB and put it in a more convenient box that is in a holder on the right side of the door. As with most other IoT applications, I can’t see the point of going IoT for this, and I’m surprised we haven’t seen an IoT toilet flush yet.

    1. There’s a chap in Holland who charts toilet closures on the internet. I use water consumption meter as an indicator of flush and then take preventative action (turn fan on).

  3. Interesting method. I would have probably gone strictly mechanical, with a 3D printed cover for the switch with a bump on/bump off toggle for the door to hit. That, or a dummy mechanical switch in the natural location on the other side of the door with two strands of fishing line and some pulleys to route up over the door frame.
    Or heck, this same servo setup with wires running to a manual switch on the other side of the door frame.
    But, if he wanted a reason to play with IOT anyway, well done.

  4. Although, strictly speaking, IOT should mean that the devices are connected to the outside world via the Internet, I find it a convenient term for networked devices that can work together even if they are not always accessible outside their local network environment. I use the term “Cloud Free IOT” for devices that are networked together but do not depend on any external service to operate. They may be externally accessible in a controlled and secure manner (e.g. VLAN or similar) but do not give over their data or control to a third party. I have designed and built my smart home system to work this way. This approach provides much more privacy, security, resilience, lower cost and flexibility that “cloud centric” systems like those from Google, Amazon etc.

  5. “non intrusive” and “not messing with mains” is touted as successes for hacks like this. but they shouldn’t, because if they were “intrusive” you wouldn’t have to print a huge fixture to hang on the outside of the switch. and now you’ve made the switch itself useless. anybody who knows their way around an arduino should be able to flip a breaker and use a DMM to check voltage on two 120V wires. put some voltage control inside the switch box in a way that makes the switch still useful and doesnt have all that junk stuck to the wall. you could do this with one relay.

  6. I guess one reason to do this mechanical switch solution is: “because I can”. The regulatory headaches with almost anything these days are ridiculous and sterilizing, whilst you go far out of your way to avoid touching that holy grail. The costs mount for a homeowner in the name of protection and safety to do electrical or gas stuff using a licensed tradesperson. Otherwise, if you are OK to change your own switch, there are plenty of Insteon, Z-wave, UPB and other replacement paddle switches that have means for RF or PLC remote control. That is also a quick way to solve 3-way / 4-way switch issues without having to rewire.

  7. This is a terrible solution for this problem. If you are content to use you phone, then buy a smart light bulb for the room. One step further is to get the Phillips hue button for it and mount it in a better spot.

  8. LOL… Oh for Petes sake. Just glue short piece rubber hose or a spring to the door.
    Cut the hose or spring length so as it’s just long enough to push the light switch when you swing the door all of the way open.
    Just remeber that you don’t want to damage the switch, just flip it.

    1. Opening the door doesn’t equate to wanting the light switched on though — the room has a window and natural light, the problem solved is just that the light switch is located behind the (open) door but can now be switched on/off from anywhere in the room/house/world with an internet connection

  9. I’m still waiting for the day someone designs something like this and doesn’t stop at the proof of concept stage (which I’m guilty of myself more than I care to admit). It wouldn’t take that much more effort to re-print in white and design the thing to look reminiscent of an actual switch to make it blend into the room a bit.

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