Zero-Intrusion Wireless Light Switch

What do you do if your light switch is too far from your desk, and you’re in a rental property so you can’t put in extra wiring to install an electronic control for it? Get up and turn it on or off by hand? Of course not!

If you are [Guyfromhe], you solve this problem with a servo attached to a screw-on light switch faceplate, and you control it with a pair of Arduino/nRF24L01 combos. It’s a pretty simple arrangement, the wireless link simply takes the place of a serial cable that instructs the Arduino on the light switch to operate the servo that in turn moves the switch. The whole thing is triggered through his home automation system, which in turn responds to an Amazon Dash button on his desk. Yes, it’s complex. But turning on the light has been automated without intrusion into his landlord’s domain, and that’s all that matters.

On a more serious note, he’s put some Arduino code up on his write-up, as well as a YouTube video we’ve put below the break.

This is by no means the first such switch we’ve seen, after all we featured a nicer 3D printed servo light switch the other month, and one with a breadboarded Arduino in 2015. While we’re at it though, it would be nice to see a few designed for European switches too.

51 thoughts on “Zero-Intrusion Wireless Light Switch

    1. Maplin (UK) and Amazon UK sell a timer switch that fits over standard switch with no mains wiring required.
      I’m tempted to buy it and hack it, but no sure my kung-fu is strong enough lol.
      Product code A07QY on maplin and on amazon it’s by switched on products and called “Light Switch Timer – Mains Lights Retro Fit No Wiring Police Approved Security Digital Wall Timer Switch”

      1. A long as it’s police approved :P That thing is considerably more expensive than this project and doesn’t have any kind of connectivity… You can’t use the light switch anymore with that thing on the wall, good luck when a guest has to spend 15 minutes trying to figure out which button to press to turn the lights on :P

    2. This one is in my office, only I have to look at it… For the “public” areas I have used smart bulbs… This was just a tinkering project… I could probably put a white box over the servo and make it look nicer but this isn’t about looks or WAF…

        1. That is extremely cool, I will probably try and make one of those just for fun, though I see you’ve realized that it won’t fit in a box and it violates a bunch of electrical codes… Codes be damned though, dremel a hole in the back of the box and run your pull wires out of the box and then you won’t have HV/LV in the same box :P

  1. As long the screws are not sealed, I would look if I can hide a remote switch module in the wall. Like taking the module of a Sonoff out of its housing, wrap it in polyimide tape for insulation and throw it behind the switch, if it does not fit with its housing. I doubt any landlord will check into the switches.

    1. I actually have a Sonoff coming and I had thought of that… a few problems with that though… 1) depending on the age of the property it might not fit in older tiny boxes (I’ve had boxes regular switches barely fit in), 2) not all light switches have a neutral wire in the box.. I still may see if this is viable when my Sonoff gets here though :P You could put the Sonoff inside the fixture itself but not everyone is comfortable screwing with mains level stuff… Also I find the servo cool cause you can see it moving…

      1. OK, the neutral is an argument. In the fixture it is in every case. You could then just leave the switch on, but then there is a problem with guests.
        I had it similar in the toilet, when I installed a motion sensor: Guests switch the light off and it’s completely off. First idea: block the switch with some tooth picks, until it is not movable any more. But somehow somebody manged it to work them out, because he really wanted to switch off the light (he did not switch on himself). So I had to screw the switch out and bridge it. Now there is the occasional question about a “defective switch” but there is light.

        1. Yup, you can always go at the fixture but then you need to be able to control it which adds complication to the thing… I had the problem the people the renovated the bathroom decided to put the light switch on a different planet.. I added a motion detector and an x10 stick a switch though I had to add instructions for the switch because no one could figure out how to use it :P For the most part they just let the motion detector turn the lights on and off and don’t bother trying to futz with the switch… You could replace the switch with one of those blanking plates then you’d just hear “Where’s the…oh” a lot :P

          1. The slamper doesn’t let you control it with the switch and you need room in the fixture to install it… It looks pretty big…I even had trouble putting the tiny X10 socket rocket in a lot of fixtures…

      1. Why not? :-)

        Of course not directly but with a series resistor of like 100k to 470k and a 3V3 Z diode that could be done. Of course that gives you a pulsing 50/60Hz signal, but easily detectable in software. If you want a steady logic level you need 1-2 more resistors, a diode and a cap. But you need a “HOT” for supply and a switched wire.

        1. I’ve already got a hot-switched coming from the physical switch itself, if I wired it in that box I could use LV but if I stuck it in the fixture I’d need something like that, but I’d also need to be able to run the full voltage to the light after… This being one of my first hardware projects I don’t think I’m ready to start jamming resistors and caps attached to mains into my ceiling and hoping it doesn’t start on fire :P We’ll see though…

  2. “While we’re at it though, it would be nice to see a few designed for European switches too.”

    this may be not possible as in EU there are thousand of different switch designs and in US just 2.

    1. I have a few of those, you need a neutral wire for most of them and they usually cost $50+ Also they don’t fit in older / small boxes… I could make this look a lot nicer but that’s not the point… I have smart bulbs and other solutions that you can’t see in rooms people other than myself actually see…

  3. As a hack, cool. But, does he know about WeMo’s or TPLink’s WiFi switches? I control mine thru the cellphone, computer, and if needed, an Arduino could too, remotely, with a button, etc. Those don’t need extra wiring, just replace the current switch, and when you leave put the old one back in. Simpler, cleaner, and price is not that much.

    1. Yes, I own a pair of Wemo insight switches, a regular Wemo switch and a Wemo light switch as well as a handful of smart bulbs and gateways and even an X10 switch replacement… This was more of a learning experiment with some convenience for me at the end… It’s in a room no one by myself is allowed in and those Wemo light switches are about $45… I spent about $8 on this project in stuff I didn’t already have… There’s lots of commercial things out there that look nicer but that’s not really what HAD is about…

    1. Not of this particular solution, but that can control your lights yes… If you look at the reply directly above I listed about 4-5 of them that I own and use on a regular basis… This was a DIY project with parts I had lying around… This is Hack a Day after all, not “Go to the store and buy a thing and then plug it in a day”…

  4. There are several usability issues that solutions like this don’t solve. Not to mention the aesthetics and not exactly non-instrusive aspect. Wifi or 2.4G based solutions will have very poor range and structure penetration.
    Here’s my take on Arduino-based wireless light switch – definitely intrusive but no hanging wires or annoying servo noises or invisible in the dark. It can also take PIR sensors or pair with other remote PIR based nodes to activate lights etc. A 3rd party user reviewed this solution that is available as a configurable kit. Guide here: https://lowpowerlab.com/guide/switchmote/

    Review:

    1. Definitely a neat solution. I’d love to build one of those kits and maybe someday when funds are available I’ll pick one up… As it stands though from your site it looks like this kit costs around $50 before shipping which is pretty close to the cost of a commercial solution.. As I’ve said before I spent $8 on this project… I’d like to hear about the usability issues you mentioned… I have no problem controlling this via my automation system, my dash button, the switch behind my desk or the switch on the wall… As far as range goes, I have good WiFi coverage all over my house and even this simple low powered $1 device can communicate through a floor and across my home just fine. My solution though not pretty is cheap and effective. In my case the hanging wires aren’t an issue in _this room_ and I actually happen to like the servo noise… The whole idea being this is a DIY project not a commercial kit. The invisible in the dark “problem” could be solved with a little glow paint or an LED if I thought it was a problem, but I haven’t had any issues finding my dash button or switch and worst case I can ssh or access my automation system from my computer.. I have my own automation system that deals with PIR sensors and other types of sensors…

    1. I actually had a very similar thing to your original setup, I’ve been using this for over a year now but prior it was running on a laptop because the light switch is on the opposite wall from my PC and I didn’t want a cord running across the floor to trip on… I finally got around to adding the wireless modules and the switch and making it self contained this past week… Before I had a python TCP server running on the laptop so my automation machine could send it commands and so I could use my dash button….

    1. I don’t know if one of those things would hold up to the repeated torque… I have those in my house and they do work… I covered the hot glue with a paper box so you can’t see it anymore at least… I suppose if it ever falls off I will one of those 3M strips and see how they work… not too worried about removing it though,,, Wall plates cost less than one of those strips…

  5. For any stragglers, I got a $5 WiFi shield the other day and have de-coupled the “remote” Arduino from my Pi. I can now place it anywhere and my scripts can work on any machine on the LAN or via a web browser. Update linked in my blog.

  6. Nice. When I discovered this problem in my office (the light switch is three feet away on the far side of my desk), I just grabbed the 3-wood out of my golf bag in the closet and propped it up beside my desk so I can use it as a finglonger to hit the switch.

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