Home automation - making a dumb ducted aircon smart

dimitryp on 23/11/2017 - 13:18
Last edited 23/11/2017 - 16:31

Hello ozbargainers, i'm hoping someone could help me with a home automation aircon hack.

As part of my home automation project i'm trying to "smartify" my old ducted aircon. Want to be able to at least on/off control it via Alexa or a phone app.

The aircon is a 10yr old Temperzone ducted multi-zone system which has a proprietary interface (no popular smart thermostats are compatible, i've checked), and also doesnt come with an IR remote. The only way to control it is via a physical wall panel (and this sends signals to a control box that's in the roof void).
The only 2 things that would work, from my research, are 2 smart aircon systems made in Australia. One is MyAir, which requires a partial refit to the tune of $3000+, the other being AirTouch, which will only do on/off control for my system to the tune of $1200.

I was hoping to achieve this in some other way, at least for on/off control.

The wall panel has a momentary-press button for on, and another one for off.

Would there be some Alexa/z-wave enabled device that would allow me to manipulate these on/off signals? I dont mind doing some wiring/hacking, etc.
Or are there even some remote-controlled-physical-button-pushers? Is that a thing?
Pictures of wall panel are here:
https://imgur.com/a/q2hij

The on/off buttons work with the contacts labelled SW1 on/off.
Not sure how the signal is sent, i imagine its some type of 12v pulse? A fair bit of pressure needs to be applied to the rubber buttons for the press to register. Can i get some remote-controlled device to send this pulse if i wire it to the switch contacts?

Any ideas? :)

thank you!

p.s. on further investigation, there's not 2 buttons for on/off, its just one wide toggle-button with 2 labels. I've been pushing either the left or right side depending if i wanted on/off but i realise that its just a toggle! The button much close the 2 contacts underneath it to enact the toggle..?

Electrical & Electronics

Comments

  • [Deactivated] on 23/11/2017 - 13:23

    Oopps. Sensibo won't work

    • dimitryp on 23/11/2017 - 13:35

      Yep. My system doesnt have IR remote control capability. :(

  • npc on 23/11/2017 - 13:38
    +1

    Perhaps use oscilloscope to record the signals in the wires between the control panel and the aircon. Then use RPI to repeat/inject them in the control wires (On/Off, +/- temperature etc.) RPI is also connectable to Alexa via AWS+Lambda for example.

    • dimitryp on 23/11/2017 - 13:41

      That's a very interesting idea.. I didnt know this was possible.
      Could you link me to what kind of oscilliscope and what kind of an RPI (what is that?) could do the trick? Alexa-controllable ones would be ace.

      • npc on 23/11/2017 - 14:07

        Well it's kind of hacking approach that I suggested and it requires some skills in electronics and programming. RPI = Raspberri PI. Oscilloscope - any.

        • Gronk on 23/11/2017 - 16:32

          Could you not just read the data via serial, provided A/C the wire wasn't running more than 5v?

        • abb on 24/11/2017 - 14:54

          @Gronk: Well, if it's TTL (i.e. 5V) serial, then yes, you can use TTL serial.

          It could be RS-232, RS-485, I2C, some proprietary thing, etc. An oscilloscope is the best (although also most expensive) way to figure it out, apart from breaking open the box and looking at the chips it uses.

          edit: just noticed OP's photo - 12V, Data, Clock, Gnd. So it's not straight serial. Probably I2C.

    • peter_mcc on 23/11/2017 - 15:05
      +1

      The basic concept is sound but if the OP doesn't know much about electronics they may end up killing themselves - sometimes the control signals aren't nicely isolated from the mains. Plus you need to be able to generate the correct type of signal - right voltage/etc - which is going to need some sort of interface circuit from the RPI. Doable but not novice level stuff…

      • npc on 23/11/2017 - 15:12
        +1

        So many ways to kill yourself these days:) This is not the easiest one but everything is possible.

      • dimitryp on 23/11/2017 - 16:34

        hmm. I'd definitely classify myself as a novice in this field. I'm an IT consultant by trade, so i understand "systems", but have never had to do any pcb electronics work or code for hw.

  • sane on 23/11/2017 - 13:45
    +1

    Yeah, Australian systems have a habit of being proprietary nightmares.

    Best bet is to see if there is a controller upgrade for the system you have with IR remote (they often offered it, though you might need to go looking through old parts stores, ebay, etc.). They usually just plug in. I think your supplier is just a distributor for other manufacturers, so you'd need to find out what model, range, etc. (manual is a good starting point).

    Then use something like a Broadlink unit to provide control. Get the RM Pro and it has a temperature sensor built in, then use something like Home Assistant to fake the automation.

    Wiring the actual switches is potentially possible (though I'm sure someone wouldn't like it), but you have the problem of powering whatever device you hack together.

    • dimitryp on 23/11/2017 - 13:47

      I've contacted Temperzone, there arent any upgrades, IR or otherwise, available for my system.
      I dont mind doing lots of wiring, providing power supply, etc, that's not the hard bit.

      • sane on 23/11/2017 - 13:55

        Overload the switch with momentary make relay circuit board, controlled by a RaspPi then.

        For double brownie points, include mic/speakers and make the RaspPi also be a fake Echo or Google Home.

        PS here's their trade site, if you haven't found it https://www.temperzone.biz/AU-Home/Product-Overview/

        • dimitryp on 23/11/2017 - 14:03

          Any guides online on how to do what you're mentioning above?

          And yes, i've contracted Temperzone via that site, no luck on upgrades.

        • sane on 23/11/2017 - 14:08

          @dimitryp:

          Loads of them, that's why I suggested the RaspPi, there are loads of tutorials to pick from.

          eg http://www.instructables.com/id/Controlling-Any-Device-Using…

          All you really need is the relay wired across the existing switch so you can fake the 'press'. From there it's software.

          Obviously you won't be able to get sensor data that way - but secondary sensors are probably better anyway.

        • peter_mcc on 23/11/2017 - 15:06

          That's a fairly safe and easy way to do it.

        • dimitryp on 23/11/2017 - 15:10

          @sane:

          Thanks, I'll investigate that guide and see if it's something I can muster
          Will need to invest in a Pi and relay, looks like. Still cheaper than full aircon refurb!

  • bdl on 23/11/2017 - 14:09

    I got one of these from Amazon - have you checked if these work?

    https://www.luxproducts.com/geo/

    • dimitryp on 23/11/2017 - 15:08

      This looks similar to the nest or ecobee thermostats. They won't work with my setup as they expect standard wiring to be present, while my system is completely proprietary and passes all data via one data wire according to a protocol temperzone have devised.
      This is why I'm here looking for less orthodox solutions..

  • No on 23/11/2017 - 15:31

    While it wont look nice and might need a bit of messing around to get it to work without obstructing the door you could look into this kind of product:

    https://www.amazon.com/MicroBot-Push-Wireless-Automation-Pla…

    • dimitryp on 23/11/2017 - 16:23

      Thats certainly an interesting idea, and doesnt require wiring or coding!
      I wonder if it'll be able to "fit" onto my thermostat. The on/off button is annoyingly in the middle. I guess i could obscure some of the screen, thats probably not a problem. Will consider, thanks!

  • stampella on 23/11/2017 - 15:38
    +1

    I don't see it as complex. Most likely you just need to send a (likely to be 12v) pulse through the momentary button path. Best to arm yourself with a multimeter and see what goes on the button pads.

    Note that these pads looks a bit worn off (understandable after the use) or oxidized. Try to gently clean them (hard rubber eraser, maybe some m. spirit) and it will make it easier to press them, unless the contact on the button is f-up too.

    If you only want on/off control, then likely all you need is the cheapest arduino based clone you can find. https://www.ebay.com.au/itm/New-Pro-Mini-ATmega32U4-16MHz-5V… This will be plenty for you, and small enough to be tucked in the same enclosure if you get creative enough I think.
    You will also need a way to connect the board to the network. ESP8266 is a path I would investigate, as is likely you will have good wifi coverage in the house.
    From there, you can do and integrate it the way you want. Further researches in the panel might enable you to have a full fledged online climate monitoring and control system.

    BTW, this is likely one of the best scenarios to approach this kind of hobby. A complex enough, but not too complex aircon unit board; simple double sided pcb design and only through-hole chips for the whole board logic (at least the likely to be interesting portions).
    It is likely that most of the fun happens in that U1 DIP chip. Start with just a multimeter.
    May not even need a more complex approach or tools (if you guys have oscilloscopes lying around feel free to send me one).

    Oh yeah, see if you can leech 5v from somewhere on that board, or you'll need to sort out power supply to your arduino and wifi module too (watch out for simple linear regulator…especially if you plan to close them in a small plastic box without heat dissipation).

    • dimitryp on 23/11/2017 - 16:29

      Thanks mate. Could be an interesting approach.
      Could you point me to a guide on working with an Arduino like this for my use-case? Not super sure where to start, what to wire and how to supply power. Chip looks pretty barebones!
      thanks v much

    • peter_mcc on 23/11/2017 - 23:16

      Don't feed 12V through the momentary button path - for a start the circuit is likely to run at 3.3V or 5V - injecting 12V will probably let the magic smoke out.

      It would be much safer (for the wall controller but also you) to simulate the button press using a small relay to "short" out the pads like the physical button does. You could use a low current relay like a "reed relay" but you'll probably still need a transistor or something to drive it (they draw 20mA at 5V).

      • dimitryp on 23/11/2017 - 23:49

        not being sharp on electronics i'm not sure i completely understand what this entails.
        Any docs online showing how to do this? How do i power this?

        • stampella on 24/11/2017 - 12:52

          My best advice is to get an Arduino and start playing with it, independently and outside of this control panel and project. Turn on leds, read values from a few sensors, combine the two things together and grow on from that.

          I can guarantee you that it is not that difficult, but be prepared for some grinding and a somewhat steep learning curve if you know 0 about electronic and programming. You have a HUGE amount of literature freely available online. Just controlling a beefier transistor that in turns controls the switch is something that you can learn how to do in a week or so.

          The BOM for this project probably sits below the $100 mark (for a smart ozbargainer at least) and it would require about a month of dedication (and I mean, daily dedication) to get it done, including learning the basics.

      • stampella on 24/11/2017 - 12:41

        Yeah, thanks for pointing that out. There is an adjustable voltage regulator there (VR1). Judging from the other components on the board you can have there something from ~3.3-5V. Unless you want extra fun, don't change the setting in the voltage regulator (don't turn the screw).
        Note that I doubt it may be able to power both an MCU AND a communication module to connect it to the network though. You will likely need your own power supply circuit.

        A relay and a transistor would still miss the other portion of the equation though, the "smart" portion. This is where an arduino or RPI would come in handy.

    • neomathew on 24/11/2017 - 10:43

      Can I use the https://www.ebay.com.au/itm/New-Pro-Mini-ATmega32U4-16MHz-5V with a Rasberry pi W?.

      This topic is getting interesting, thanks for sharing. I am sure everyone wants their dummy aircon to stop working hard and start working smart!.

      • stampella on 24/11/2017 - 12:45

        If you have a RPI W you don't actually need another MCU. You can do everything with it and better than with that puny 32U4.
        Note that this is not the lowest available price for that board. The lowest I got was probably below the IC cost itself (something like 1$ delivered).
        Also note that, while it is a good board for playing around, it may not be the best choice for critical/production applications. May do fine, may stop working after a few weeks.

  • dimitryp on 23/11/2017 - 16:32

    p.s. on further investigation, there's not 2 buttons for on/off, its just one wide toggle-button with 2 labels. I've been pushing either the left or right side depending if i wanted on/off but i realise that its just a toggle! The button much close the 2 contacts underneath it to enact the toggle..?

    • peter_mcc on 23/11/2017 - 23:16

      It probably has two conductive pads underneath - one on each side. So while the thing you touch is one big button there are actually 2 behind it.

  • dimitryp on 24/11/2017 - 10:54

    It's also been suggested to me that i could use a voltage-free relay to "short" the on/off contacts on the aircon panel, which might be an easy and automation-ecosystem-ready way to do this
    something like this
    https://capitalsmarthomes.com.au/collections/goap/products/g…

    • sane on 24/11/2017 - 13:29

      "shorting" the contacts via a relay was basically what I was suggesting above - and something like a Rasp Pi Zero W with something like this

      https://www.adafruit.com/product/3352

      would be cheaper than the above.

      You don't want to be injecting power into the circuit, or necessarily drawing power unless you know it is up to it.

      It's also important to realise you will be creating a 'stateless' device, the equivalent of pushing the button blind. If it gets out of sync, you won't know without manual intervention. Often such devices use effectively a single wire comms (eg serial) to the unit in the roof. Such a device might also allow you to snoop and understand such datacomms (similar to the oscilloscope idea above).

      • dimitryp on 24/11/2017 - 13:53

        just did some testing and i was able to short the 2 button contacts with a piece of wire to achieve on/off. So that's worked out at least!
        i think the z-wave device might be the go as it's z-wave integrated and basically ready to go. The Pi + relay might not even work out that much cheaper? $55 for the Pi + $12 for relay + shipping (unless i can use the Pi Zero..?). Works out close to the $105 z-wave device price.

        Yes, i understand it's stateless, but i can tell the state by looking at my ceiling ducts (i've attached little bits of coloured tape there to spot air-flow) :D

        The stretch-goal challenge would be to be able to manipulate the Zone toggle buttons. These arent the same type as the on/off switch, they're part of a keypad that feeds data into the PCB via a 9-wire serial cable. Although the buttons are still pushed, so is there something shorting some wiring in the keypad to achieve the toggle? Or is it more complex than that?
        I've added a photo of the back of the keypad to the end of the original album
        https://imgur.com/a/q2hij

  • dimitryp on 25/11/2017 - 11:28
    +1

    I ended up going for the z-wave dry contacts module as a decent mix of cost-effective & easy. Will use this to short the contacts that control the on/off function under the on/off button.
    Will report my results after i receive the module in the post and wire it up.
    Thanks for all the great ideas here guys!!

    • rompastompa on 02/07/2018 - 15:22

      How did you go?

      • dimitryp on 03/07/2018 - 09:38
        +1

        Oops, forgot to report results. Yes, it worked! Was very fiddly wiring the fry-contacts relay into the on/off button, but got that working reliably eventually. Now have good voice control over the air-con :). Only on-ff [cant do temp change or zone change], but that's still very nice.

        • KRM123 on 24/07/2018 - 10:55

          Do you have functionality now or is it simply on off? I.e can you adjust mode and temp and other stuff?

        • dimitryp on 26/07/2018 - 10:48

          @KRM123: No, only on-off, unfortunately. To get other functionality i'd need to wire in one extra dry-contacts relay ($100) per button i want to automate, which would be quite a few additional buttons and a lot of fiddly tinkering with the panel. So i've decided to just be happy with on/off for now.

  • twocsies on 03/12/2017 - 11:18

    Find your local Hackerspace (google it). I'm sure you will find knowledgeable and friendly people there.

  • MrZ on 26/07/2018 - 11:27

    Speaking of "dumb" air conditioners/heaters, does anyone know how to get a newish ducted system to turn itself off when it reaches the right temperature? The old unit (a Lennox gas system) we had would do this, but the new one runs almost 100% of the time. Occasionally it will turn off for maybe 30-60 seconds, then come back on again. When set to heat, the house becomes like a sauna because of this, even on the lowest possible setting of 18C!

    • dimitryp on 27/07/2018 - 10:55

      my guess is that your thermostat is in an area where the true temperature isnt sensed?

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