Superhouse, a deeper conversation about the hardware workings

my edits since yesterday

Hi Jon,

Love your superhouse video series. It is extremely well presented and very concise. Your Superhouse setup is amazing. Very impressive. I was hoping to start a conversation here to pick your brain further.

I am involved with a new build for a Victorian based house which is scheduled to be finished in the next 12 months. Which I am interested in setting up in a similar fashion to Superhouse. I have some background with electronics and Arduino, and openhab and mqtt look very simple in regards to logic workings. I am a novice with Home automation though. So the main gist of my queries is related more to the hardware setups.

So I will probably rant abit my understandings of how you have things setup and interlace some questions throughout, which I am trying to decipher. If you don’t mind of course…

So I understand the Distribution Board setup you have, in a broad sense. That being the centralised Star wiring schema for the load devices.

  1. I believe that is referred to as the LV lines? Over 50 vac but under 1000vac is low voltage, which is where the 240v lands.

I get how they are activated at the 12v side via the ethermega however. Ahh episode 24 about 9 mins, (no longer lunchbox) this then connects DIN–Ethermega(lunchbox mega)–Signal(pulls 5v to ground)–MQTT–Openhab and giving you the network controlled publishes and subscribes. I think… I need to review that some more. AHH lunchbox is shiny now and exits simply via Cat5/6 to to patch panel.

You have those devices going into the din relays, what are the other options here?

  1. Why are they dipole? I need to look into single and dipole relays, that is over my head currently, I guess I don’t understand the need to loop the active and neutral?

  2. Do those relays allow you to dim/ramp the light intensity? I assume so, but it wasn’t clear in your videos.

  3. Do those relays allow you to control ceiling fans? Do you need a din fan capacitor/controller to do that or is there some other solution? If you have ceiling fans how are you controlling the switching for them? As an add on to that how are you controlling your reverse cycle AC - The remotes are very noticeable in your videos.

  4. You mention blinds as load devices. Can you expand on that in a future episode? how many blinds/relays are you using? Are you using the dooya motors or something else? As a fellow Melbournian I am interested in your solution to blind controls. This contrasts your window openers/linbus system, which I believe you wired up via the cat5.

  5. Lastly on the DB and sub DB, all your GPO/sockets are still from the main DB box at the front of the house in a daisy chain circuits? That seems to be how its done to my understanding, even in cbus. I could be mistaken though. I know less than nothing about cbus

So that gets us to the switch side which you have wired via cat5, with upto 4 gang max per cable, then into your awesome rack mount Arduino button controllers. Again this is the Star wire schema. It sounds amazing and really light weight.

  1. This would commonly be referred to as the ELV lines ((well POE really isn’t it, not ELV as such like between the switchboard lunchbox mega)) so I guess not ELV.
    How does this contrast to CBUS switch wiring? Clipsal Iconic with the mech 40s seems to go back to daisy chaining and using bluetooth to manage the switches, which seems like alot of extra radio signals around for interference/jamming. So I guess I am basically saying here I don’t understand how cbus wire the switches and my google-fu is not being helpful. if you can shed some insight onto how cbus normally wire switches for home automation that would be most beneficial to myself as a HA novice.

  2. relates to Q2-Q4 Can your switches be used to dim/ramp the lighting and or control ceiling fans in your current setup. My understanding is you can do it via openhab with timers and scenes. I wasn’t clear on if you are doing these types of things, and if you have the capability of doing it directly from the switches.

  3. How would your setup go for passing building inspections on a new build? Would they basically just ignore your switches because they are ELV/POE or something? Would a typical building inspector pass a building with no light switches? I see how the ELV in switchboard passes now double shielded cat cable

  4. What would you do differently in a new build while you have frame access now that you have so much experience to build on? e.g. Would you do something like have a whole house battery system for UPS provisioning? failsafe your light switches somehow?

  5. Are your alarm and camera systems integrating to openhab either as sensor inputs for automation or using openhab to control those devices? I assume you are still running the Annke cameras.

  6. You briefly mention Nodered, is that something you are using in this system? It seems like just openhab and mqtt from the rest of your explanations. or perhaps not, flow based programming I have less of an idea about than cbus. HA, I don’t think I need to know this, YET

  7. You stated you had an electrician wire all this up. Can you pass on his contact details if he is interested in more work?

Thanks for taking the time of creating this resource, it is extremely valuable. Oh and if I have over looked the answers from the comments on youtube I apologise, I haven’t looked there too deeply yet. Information overload was kicking in, it was handy for myself to write this all down Sorry for the essay.



I was wondering why you used 12v relays instead of 5v relays, since the relays are controlled by arduino output pins. I would think that 5v relays would require less hardware to latch.

One problem I have gone over and over,regarding relays, is weather to use self latching relays for the lights. Latching relays require no power to maintain state and, of course, they retain the last used state during a power failure. Actuation is a bit more complicated, requiring a positive pulse to activate and a negative pulse to deactivate. Also the cost is about twice as much as a similar standard DPDT relay, which adds up when you consider that there are, maybe 20 in an average house.

For my house I finally settled on using the readily available (and cheap) 4, 8 & 16 relay boards that are available all over the net, wherever arduinos are sold, Bangood, eBay etc. Using a multiple relay board makes it easy and inexpensive to build in extra, spare relays, in case of failure. If one relay fails, you just mark it dead (with a sharpie) and move the jumpers over to a good relay. The cost per light can be as little as $2 per fixture, or less.

If UL or RU approvals are a concern, the boards are not approved, but the relays generally are. I read an article at the UL site about approval criteria. It seems that they will approve components but that does not automatically approve a device made with those parts. It seems that it becomes the decision of the inspector weather to approve the hardware installation, or not. I don’t know if my inspector will pass my relay board without approvals. He might just be stunned enough, when he sees my lighting setup, to pass it…his call. All I can do is to make the installation look as professional as possible, making it look like it won’t explode or catch fire spontaneously. In my opinion, code regulations are running far behind the technology when it comes to smart homes. Usually, when faced with something like this, I would hold off any fancy modifications until the inspections were finished and I was free of the inspectors. Unfortunately, there is no way to do this since there is no way to switch the lights without using the relays. I did look over the web for UL approved relay boards but the only thing available, that I could find, was expensive, commercial units or really high end residential devices, usually provided by companies like Lutron, Elan, and Crestron, to name a few. The later being dealer only items. More on this subject later.


Hi Nic,

That’s a big list of questions! So my answers make sense I’ll try to match up the numbering.

  1. Yes, those are LV. Many people are surprised to discover that domestic mains power is referred to as “low voltage”, but of course that’s from the perspective of power companies that deal with kilovolts.

  2. Originally it was the default choice. The commonly available relays and bases were DPDT, so I would have had to go out of my way to find single pole relays or just use one pole of each relay. When the electrician was wiring it up we looked at it for about 30 seconds, considered taking all the neutrals to a common terminal block and just switching the actives, and decided it was actually easier to simply terminate both the active and neutral at each relay. It made the cable routing easier in the switchboard. There was very little reason for it except that. However, now that it’s been done this way, I actually like it and so does the electrician, because it means we can totally isolate any endpoint cabling. If he’s working on something in the house, he can just pop out the relay for that endpoint and know with 100% certainly that the cable is fully isolated from both active and neutral, so he can work on it in complete safety while the rest of the house remains live.

  3. No, I can’t do any dimming with the relays. That’s a big topic that I plan to cover in future. It will require the relays to be replaced with something else, such as an output controller using Triacs. However, because the cabling all comes to the central point, I’m future-proofed for these sorts of changes. The DIN-rail mounted relays can be removed and a new output controller dropped into their place, and then loads can be dimmed.

  4. I don’t have any ceiling fans, but the relays are just mechanical contacts so I don’t see any big problems with using them to control fans. Controlling fan speed is another matter that someone brought up elsewhere on the forum but I haven’t done it myself. We have gas heating, evaporative cooling, and reverse-cycle airconditioning in different parts of the house, so I have everything! For the aircon I have an IR blaster type setup with a Particle Photon but I don’t like that at all. I’m planning to cover HVAC control in future episodes. In fact my next 2 project episodes will be about sensors for exactly that.

  5. I’m using blinds with 240Vac tubular motors supplied and installed by Global Blinds (also here in Melbourne) controlled by relays in the same way as lights. Some of the relays you can see in my switchboards are for controlling the blinds. They’re twin-active, with one active for up and one for down. I want to cover this more in detail in future. I’ve spent a long time working on blind controllers including some with WiFi built into the motor itself (long and painful story)

  6. Yes, you’re correct, my GPOs are currently wired in a totally traditional way. There’s no control of them, only monitoring from the switchboard on a per-circuit basis. Another topic for future videos!

  7. CBUS uses a shared bus topology, so you can daisy-chain the cable around from one device to the next. Each device has a unique address on the bus so they can communicate with the master. If you’ve seen something like 1-wire bus or I2C, it’s conceptually similar. I’ve done a bit with CBUS (and I have a bunch of CBUS modules here wired up in a test system) so I could probably cover that in future.

  8. I don’t have any dimming right now except for LiFX lamps which have power constantly supplied and are controlled via WiFi. Those are the exception in my house, most lights are “dumb” and controlled centrally with no dimming. Right now the button controller only sends a button press event so that OpenHAB can detect when a button has been pressed, but it would require a tiny software change to make it send both press and release events so that it’s possible to determine press duration. For example, a press event could cause the lights to start fading either up or down, and a release event would cause the fade to stop. I haven’t done this though because I don’t have the hardware for dimming control. Yet!

  9. The switches still need to pass electrical inspection because they use fixed cabling. Regulations here in Australia are quite strict about any fixed cabling, even if it’s ELV. Even things like speaker cables run through a roof need approval, according to the regulations! So in our case I made sure to involve my electrician (who has extensive experience with both domestic and industrial automation) to make sure it was done correctly. If you’re doing a new build I don’t know how the building inspector would react. In my case it was a renovation of the existing structure plus the extension, and my electrician was involved in the process right from the start so he did everything according to regulations and the building inspector just seemed to accept it.

  10. That’s a great question. I think what I’d do at framing stage is make sure there is easy access for additional cabling in future, such as putting in conduit running through noggins etc to allow cabling to reach between the ceiling space and light switches mounted below the level of the noggins. Probably also more sensors, such as installing flow gauges in water pipes while at the framing stage and all the pipes are exposed. Plus leak detectors inside walls.

  11. The cameras aren’t integrated at all right now, but security motion detectors are. They’re monitoring by an Arduino which tracks their state and publishes motion events to MQTT. It always does that whether the house is occupied or not. Then other code watches those topics and can do things like turn on lights by calling the OpenHAB API. I have some “items” in OpenHAB that are just variables with toggles associated with them, and I’ve grouped them into a “settings” frame. So I can navigate to that frame and toggle “auto bathroom lights” for example, and if the setting is on, motion in the bathroom will cause the lights to turn on for a preset time.

  12. Right now I don’t have Node-RED actively part of the system, but I plan to replace my simple rules engine with Node-RED soon and do a video about it.

  13. I’d rather not publish personal details here, but I can do that by direct message.


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I could have used either 12V or 5V relays, but I chose 12V because it gives more electrical isolation for the microcontroller. In either case you’d use low-side switching (with + supplied to one side of the coil, and something like a FET that connects the other side of the coil to GND to activate it) so it makes no difference to the complication of controlling them. The difference is that by supplying the relay with 12V, it can come from the general 12V supply that I feed into devices before it’s regulated down to 5V or 3.3V for the microcontroller. This is important because if you run the relay coils off the same power rail as the MCU, any electrical noise they generate will be directly linked to the MCU. But if they’re powered separately, the voltage regulator that supplies the MCU will do a much better job of keeping its power supply clean.

Kinda hard to explain in words. I should do a video about this to demonstrate low-side switching.

Hi Jon,

Thanks for the detailed response. You have definitely inspired me to pursue home automation integration in my house and the new build. Your relay setup looks great and sounds like it’s easy to work with. Dimming seems to be a tricky aspect from a DIY perspective, I look forward to seeing how you deal with it in the future.

Ceiling fans seems to be another headache for home automation too. Sounds like you dodged a bullet there with your HVAC and AC setups. Ahh sensor videos! I will be watching those for sure. Blind do’s and don’t would be another interesting topic.

Yes cabling regulations seem to be strict here, I guess I can understand it even if I don’t like it. Building inspectors too I presume are understandably strict. Conduit and leak sensors are great suggestions, thanks.

So I guess I am working on updating my current super old alarm panel with some extra reed switches and trying to get that into openhab. It always seems like it is just around the corner. But it seems like a great place to start to set some smarts up for a house. Node-red seems like it will make openhab much simpler. Onto getting a Pi setup!

I will send you a message in the future regarding those private details if the need arises.

Many thanks for taking the time to reply.



For my Openhab install I plan on using a pine64 for the CPU. The pine is cheaper than a raspberry Pi, has more resources and there is an openhab distribution for it. Also there is a really great openhab, with node red, tutorial on youtube that walks you through the complete install and setup. Very well done (just like your videos, Jon).

The 5V relay boards, that I am using are opto isolated so there is good isolation of the relays. They sell din rail mounts for the boards also. Because the relays are very popular and they sell lots of them, they are really cheap. You can get them for about $2 per relay, or less. All of the designs are pretty much the same regardless of manufacturer. Due to the cheap price I will be able to install redundant relays that I can, quickly and easily, wire into the system in the event of a relay failure. Also each relay has an LED that shows the relay state, something that is handy when troubleshooting or programming the system. My workshop will be in the same room where my homerun and control panel is located.

As far as dimmers, I don’t see any reason to disconnect the relays to add dimming to a light circuit. It seems to me that you could easily add the dimmer circuit between the relay and homerun board. This would make certain that when the light was shut off, that you would not have any residual voltage going to the light, a problem that I have read about with some of the dimmer circuits. I do like your idea of replacing the relay with a circuit board that plugs into the din mount. That would make a really clean, easy to install solution. Just pop out the relay and pop in a new board, Kool. You might also be able to mount the boards inside a 3D printed box with an LED on the top.

Speaking of which, I finally bought a 3D printer myself. It should arrive in a couple of weeks. It’s a Tronxy X5S with a build size of 300mm x 300mm x 400mm. My first project is to print a case for an electric shifter for my electric bike. I converted the single speed to a 3 speed derailleur and I’m using a small linear stepper motor with an arduino tiny to control it. I wasn’t able to find a stock shifter that fit the freewheel cog spacing on the hub. I’m mounting 2 push buttons on the handlebars to shift up and down. This is kind of off topic but should be a fun, and practical, project.