SuperHouseTV #1: Home Automation System Architecture 2012 

Also, great upgrade path from POST->MQTT, get your 'stakeholder' concerns, if I took all the lights offline for a week I'd get destroyed by the wife.

Thanks! And please share your projects if you get a chance. I love to see what other people have built.

Richard Smith so true...

Richard Smithøå

Of course, I have yet to have a linux box crash on me. They get the most amazing uptimes.

Same idea here. He could have cat5e to the switches and have room for the hot/neg pair and then three other pairs for buttons. Less logic at the switches and less heat.

Nice video. You may also want to checkout the review of home automation on my blog at *bryanreviews. com/home-automation-review/* Thanks, Harlan.

It's a tough balance between keeping the videos brief enough for people to watch, but providing enough information to do it yourself. It already takes days of work (up to a week) just to produce each 20-ish minute video so I can't afford to do much more. In recent episodes I'm trying to put more supporting information in the blog post for it, with more links, diagrams, source code, explanations, etc. If you only watch the video on RU-vid, you're missing out on that extra information. There's a link in each video description going to the blog post for that episode.

Thanks!

I'll be doing a new episode with an update on the architecture when I get a chance.

+Edwin van den Akker or probably use Zigbee instead of Ethernet of Power, if it's a small home.

+vic ky By "heavyweight" I just meant that it uses a bit more disk space and CPU time than some other approaches. On a desktop class machine it's fine, but it can be slow on low power machines. Using MQTT it's very easy for small devices (such as microcontrollers with maybe a few kB of RAM and FLASH) to connect and communicate

Good idea, thanks

That's a very good point. I still have that problem, but my system has changed a bit since that video was uploaded. I'm doing an updated system architecture video now, it'll probably be the next one uploaded.

Absolutely stinging for the updated Architecture, 3/4 the way through a 1st floor addition, wiring is in progress.

+Cornel Ghisoiu If the Linux box goes down then you're right, things stop working. Luckily it hasn't failed in 5+ years of continuous use. I don't understand what you mean about controlling the relay directly from the light switch. If you do that, you may as well just have the switch and nothing else, because if the switch can control the relay to turn it on, other controls such as tablets couldn't turn it off anyway so you lose functionality

Could you set up a second server that is a clone of the first and set one to the primary and the other to the backup. The backup constantly checks that the primary is running and if it finds it isn't sends out an alert and takes over control until the primary comes back online? As you said it's been very reliable, but all things good things must come to an end eventually? :)

Yes, that's certainly possible. Clustered controllers aren't common in home automation systems, but there are already tried and proven techniques for Linux server failover (I've done STONITH setups in the past) so that could easily be applied.

Steven Luzuriaga no way. 6lowpan over 802.15.4 if impossible to use cables. tcp/ip over ethernet otherwise.

+Steven Luzuriaga Isn't Wifi good enough?

That's a common (and very valid) concern. With many modern IoT devices they depend on an external cloud service to operate. I've specifically designed my system to be all locally hosted, so there's nothing external required for my house to operate. If my Internet connection goes down (which it does several times per day thanks to the crappy router provided by Telstra) the house keeps working fine. The only thing I can't do is control the house remotely.

+Cornel Ghisoiu Yes, it's backed up, and I maintain the configuration files in Git so I can recreate the machine any time I need to. Although the cooling fan is getting noisy, so I have a Raspberry Pi here on my desk as a replacement so I will retire the old machine soon. About controlling from both switch and Linux, I don't understand how. Which one would win? If the switch turns on the relay, and the automation controller wants to turn it off, should it override the switch? But then if the controller wants it off, and you turn on the switch, then it shouldn't override the switch anymore? It's a logic problem

For schematic capture and PCB layout there are 2 leading contenders in the cheap / hobby space: KiCAD and EAGLE. Personally I use EAGLE simply because my early work was based on the Arduino reference designs, which are published as EAGLE files. However, that's a proprietary package with a free-for-hobby-use limited version and paid pro versions. KiCAD is open source and very popular for open hardware designs, and we use it at Freetronics for many of our projects. There are excellent tutorials for both packages, but PCB design has a pretty steep learning curve so you'll need to have some patience when you get started.

Thanks, I am learning a lot, and sooner or later, I might have to miniaturize a prototype.

Good questions :-) Many home automation systems do use some form of serial bus (such as RS422 or similar) to allow devices to be daisy-chained. That saves cabling time but potentially makes each node more complex. Since I was dragging the cables myself and wasn't charging myself by the hour or by meter of cable, I opted for a star configuration so I'd have maximum flexibility with everything brought back to a central point. What do you mean about a simple serial enabled button? Do you have an example? Since this video was made I've replaced all the light switches with simple button panels that are managed by centralised Arduino based boards with many inputs, so I don't have Ethernet to every light switch anymore. The cable is still there, but it's used to sense the buttons directly. Each panel now has nothing on it but a wall plate with dumb momentary-action illuminated buttons in them. I'm going to do a video about the updated architecture soon.

+SuperHouseTV That makes sense if the cost of the cable is low for you. I'm assuming the cables going to your wall switch sockets is shielded (6 wires eternet?) so you probably could have a pushbutton with a Arduino nano, (or check out the "digispark" board,) sending a coded signal to the control unit. I'm myself digging through the heap of different serial protocols so couldn't tell which one is better but I've read that i2c and "can" can communicate on up to 100m of cable at a low baud rate.

+SuperHouseTV , could you give some details about the Arduino based switch input capturing board. a schematic perhaps or do you sell these at freetronics?

My power bill is higher than a normal household, but that's more because I usually work from home, not because of the home automation. The 6 monitors on my primary computer draw much more power than the home automation system, and I spend about 10 hours / day using those! I have a half-filmed episode about power monitoring, so soon I'll be able to answer your question in detail with specific measurements.

I work from home as well and my biggest spenders are definitely my workstations. However, I have run some rough numbers and a lot of my always on devices like a handful of poorly finished raspberry pi and arduino projects running through a Kill A Watt meter show that they would cost me between 5 and 10 dollars (each) a year to run. If you have one of those at every light switch that has to add up. Or are they in a low power state until a hardware interrupt (button press) wakes them up? I suppose they could all be asleep since they don't actually do the switching in your system.

Yes, it's surprising how a small usage can add up over a whole year! I've reduced the number of devices in my system dramatically by restructuring all the light switches. They're now just dumb buttons that use the existing Cat-5 cable to link back to 2 central Arduinos (one in each automation switchboard) that handle all the switches in the entire house between them. I need to do an updated video about the new system architecture, it's much more efficient than the way I used to do it.

Ah, so you've changed it. Less capability at the switch for sure but much lower TCO. That makes a lot of sense. Thank you the response!

I'm curious about which kind of communication used to read the dumb switch signal. Did you have to boost the signal?

Use google, or any search engine,really..

+AW Yes, if the Ethernet switch fails then light switches etc will stop working. Ethernet is very reliable though. It hasn't been a problem even after many years

+SuperHouseTV when will you make more videos ?

+william roberts I want to start making more very soon, but I've been burnt out and too tired. It takes days of work just to make one video :-(

ok looking forward to seeing your next video

+Harry M What have I been smoking? How many people are going to know how to fix this if there is a problem? There may be some but you have excluded 99.9% of the market. If there is a repair issue that needs to be done no electrician in the world is going to touch this. Let's say the main board fails not to mention that it is all run by a computer. Who's going to fix it?

+notta3d This is a very important point. It's something I should talk about in a future video. Home automation often *lowers* the resale value of a home instead of raising it, for this very reason. It's seen as a risk by potential buyers. DIY systems even more so, because you can't just find an electrician who is certified for that particular system. In my case, I made a judgement call that if (when) we sell the house, I can replace the contents of the switchboard with something like C-Bus modules very easily because the wiring is already set up for it. That way a buyer won't have to worry about something that's unsupportable.

Every car runs by a computer.....

Not really, you don't need network to turn the lights on. They are connected through cables, when he presses a button, that button sends a signal to the control box (through cables) and that box send a signal to Arduino (through cables) asking to turn on or off relays. No network is needed whatsoever. He only would need network if he wanted to do it remotely, like turn on his house's lights while he is at work, so he would send a signal to his control box via internet, and the control box would send a signal to Arduino via cables. His system is not optimal though, it was 8 years ago, it's waaay easier now in 2020 with a lot of information available and new sensors/devices.

Johan Sagaert everybody already has ethernet infrastructure, so it is cheaper than rs485. and it is already connected to internet(of things)

Johan Sagaert You're right about the power requirements and cost of Ethernet infrastructure (switch ports, etc) but it was a simple way for me to get started with something basic and increment it in small steps. Since this video came out (which was more than 3 years ago) I've changed all my light switches over to simple dumb buttons connected via the existing Ethernet cable back to Arduino-based input boxes that read dozens of buttons each. That's been working great for about the last year. I need to do another video about the updated architecture.

+SuperHouseTV An update would be great Jon.

+jok yhg It's high on my to-do list, but I've been suffering a bit of burnout (not from SuperHouse, just from work and life in general) over the last year so it's been hard to get onto some of the projects that I really want to do. Too much work, not enough hours.

+Johan Sagaert Not a wonderful comment, not helpful. If you are a professional user/installer with a lot of resources, then maybe use something other than Ethernet, but for individual enthusiasts, Ethernet is well supported. Personally I use CAT5e everywhere for LAN and 1-Wire systems for simple interfacing with PC's etc. A few network switches are hardly going to break the bank.