OpenSprinkler Forums Comments, Suggestions, Requests Wanted: OpenThermostat


Viewing 21 posts - 1 through 21 (of 21 total)
  • Author
  • #40303


    I love my OpenSprinkler. I thought it was good when I bought it, but having now used it for several months, I know it’s GREAT!

    Please develop a similarly great IP thermostat.



    That is indeed in the long term plan. In fact we have already acquired the domain name last year. The main challenge was to find a good and low-cost WiFi chip. Now that ESP8266 has become widely available with great community support, I think it is the ideal microprocessor to use for openthermostat.



    +1 … I was thinking to post a similar request 🙂
    I’m delaying to buy a thermostat, if you announce OpenThermostat I will be on the pre-order list.



    +1….Me too! ?



    Sign me up!


    Mike Mathee

    +1….Me too!



    Winter is coming 🙂 … any chances to have it for this winter?



    Unfortunately we are unlikely to release OpenThermostat for this winter season. Sorry!



    +1. Ray, take my money, now! I just installed OSPi this past week–very easy install, no hitches–and was thinking about how thermostats use 24VAC for switching, just like a lot of sprinkler systems do (mine included). Of course, sprinklers use solenoids, and HVAC switching is for the control side of a relay, but both are just driving coils in the final analysis.

    A system that didn’t need a Pi, like the ESP8266 you mentioned, would be even better cost-wise, as long as it could provide similar functionality. I know that the Pi is a bit of overkill for OpenSprinkler, but it’s at such a good price point that the overkill doesn’t mean overpriced.

    Can’t wait to see this come to fruition!! Loving my OSPi so far!!




    Consider making remote temperature sensors that folks can plug into an outlet in rooms not covered by their main thermostat so that the thermostat can get additional temperature data.




    So my plan is to release OpenGarage first (ESP8266-based garage door opener). It’s pretty much finished and I will probably post it by this weekend as a submission to the ESP8266 design contest. The framework I’ve built for OpenGarage firmware (including the WiFi setup procedure and UI) will be a good foundation for writing OpenThermostat firmware.

    @Ian: yes, your suggestion about making remote temperature sensor is a good suggestion. It might not be very economic to make separate temperature sensor nodes; instead, I can have some OpenThermostat units to serve as sensing nodes which can send its data to other units.



    Hey Ray not to thread Jack but I have a lot of experience in the garage door industry, if you need any pointers on legal requirements for remote operating systems shoot me an email. At the very least UL325 compliance in the US will help fast track any commercially available product virtually worldwide. Light and sound alarms are usually the part that slows residential acceptance. I also have a lot of experience installing accessory devices on all major opener brands, so I could also provide help with how-tos and directions.

    Just shoot me an email, or private message if I can be of assistance.



    OK, thanks, will shoot you an email.

    Note that OpenGarage is essentially a WiFi-enabled door button, it does not operate the motor directly and it relies on an existing garage door system.



    I too would be interested in purchasing OpenThermostat especially if you create a version for the Pi. For what it’s worth, here’s the list of features I would find valuable. I’d be interested to hear the features others would like to see.

    Powered by the HVAC system — the same 24 VAC that powers other digital thermostats and OpenSprinkler.
    Onboard real-time clock (like OpenSprinkler) in case the internet connection dies
    Switches 24 VAC to control heating stage 1, heating stage 2, A/C, Fan (blower) from automatic to always on
    Connects to one or more wired or wireless temperature sensors
    I know this sounds extravagant, but self learning algorithms are really important for high-efficiency HVAC systems. Without self learning algorithms it’s difficult to know when to schedule the heat or AC to start in the morning because it can take an hour to raise the temperature by 1 or 2 degrees.
    Mobile app to display current temperature, override current scheduled temperature and control scheduling.

    I would suggest that rather than attempt to develop a slick looking box to mounting on the wall (think Nest), it would be better to located the OpenThermostat in the furnace room or unfinished space. Slick looking boxes are expensive and people (like my wife) are picky about how something looks on their wall. By mounting OpenThermostat in an out of the way location, the appearance of the box won’t be as important and the mobile app can handle all the functions.



    @Jonathon: it’s interesting you mentioned that the box doesn’t need to be slick looking, because a stylish look is one of the main design challenges. Your suggestion actually makes a lot of sense — kind of like how sprinkler controllers don’t have to look stylish because nobody is going to look at it every day! I guess one consideration is that for most people who do DIY installation, it’s easier to replace an existing thermostat on the wall, than to chase the wires and find out where they go behind the walls. Also, the thermostat typically has a built-in temperature sensor and should be placed where it needs to sense temperature at. But that’s less of an issue as it’s better to separate sensors with the thermostats for better accuracy (i.e. the temperature sensed at the wall hardly represents the temperature at the center of the room).



    Ray, has this gone anywhere? I am open to the idea of running network cable to my thermostat. I am in an area of extremely congested wireless and wouldn’t use that feature.



    It’s going on, but very slowly. It will be based on the ESP8266 WiFi chip, which has been working pretty reliably (as I’ve learned from the OpenGarage project). I don’t have plan to develop a Ethernet-jack based version. Sorry.



    Any time-frames for releasing more information?



    Another vote for open thermostat.

    Can you tell us any more about the HVAC power board you have in the works?

    I hope you’ll over provision it a bit as I want to modify it to control more than just a normal furnace/AC.
    I need a few extra outputs to drive 24v relays to control dampers and my attic fan.
    I also need some extra temperature sensors (preferably both RF and a network of ds18b20 one-wire sensors).
    It would be great if it also had an expansion board connector and expansion boards for both 24v controls and relays.



    I have an initial prototype board, which is basically an OS3.0 main controller board plugged into a OpenThermostat driver board (it can be powered either by USB or 24VAC if you have a C wire from your HVAC system — this is pretty much the same as OpenSprinkler’s 24VAC power circuit). On top of that it currently has two relays and a temperature/humidity sensor (which is on the OS3.0 main controller board as there is a 4-pin header for AMS2320 T/H sensor). The software is very primitive at the moment and needs a lot of work.

    You said it would be great to also have expander connector, which I haven’t thought about — in a typical HVAC system you only have a few devices (like mine only has heating and cooling, not even a fan). What would expanders to?



    My thermostat has 7 24V outputs (W, W2 for two stage heat), Y, Y2 (for two stage cooling), G (fan only), O/B (heat pump reverse) and L (fault).
    It also has connections for an outside temperature sensor for controlling when to use a heat pump.
    I don’t have a heat pump or two stage cooling (at least not in the conventional sense), but I have other things I’d do with those connections if I could.

    Here in Santa Clara there isn’t much humidity and the outside temperature usually drops below 72 in the late afternoon or early evening.
    As long as the outside temp isn’t over 78 or so, the house stays cool until the late afternoon.

    When I had the new furnace/AC put in, I added an external air inlet from the front of the house to the furnace.
    The fresh air duct and normal return air duct from the house both have 24v dampers to select which actually connects to the furnace air return.
    This lets me use the furnace fan to blow fresh air through the house in the evenings when the outside temperature drops, rather than running the AC.
    At the moment, this is selected by a couple of manual switches bolted on the furnace return and a couple of relays.
    The two-stage furnace runs at low speed with Fan only (G) or high speed with (G) and (Y) energized. For AC, it must run at high speed to keep the condenser from freezing.

    The cooling demand line (Y) from the thermostat connects to the two switches. S1 connects it on to the furnace (or not) selecting high-speed or low-speed.
    S2 connects (Y) from the thermostat to activate two SPDT relays (could have been a single DPDT).
    The R1 connects (Y) (via S1 and the furnace) to connect to the compressor (n/c).
    The second relay connects 24V to one damper or the other (close fresh air when n/c, close indoor return n/o).
    So I essentially have 3 stage cooling (low-speed fresh air, high-speed fresh air, high-speed AC) but it’s manually selected now and controlled by the thermostat’s Y.

    I also have an attic roof fan that I’d like to control.

    I realize you can’t design for my specific needs.
    If you built a board with the standard outputs noted at the top, I’d hack it to repurpose Y2 and O/B to select fresh air and to activate an external relay for the attic fan. (I’d keep the relays I’ve got to ensure I don’t turn on the compressor without setting the furnace to high speed or leave both dampers open or closed at once.)

    I plan to add wired (DS18B20) temperature sensors outside (at the fresh air inlet) and in the attic.
    (Wired because I don’t want to have to run power to them or climb up there to change batteries.)
    If you’ve got a spare GPIO pin to tie those to directly, that would be ideal.
    Otherwise I’d have to use another controller turn these signals into RF to talk to an RF receiver on the main controller board.
    I would like to use RF remote sensors to read the temperature in different parts of the house and keep the OpenThermostat itself in the furnace closet.

    I want to modify the software to use downloaded weather data together with live inside and outside temperature to decide:
    o On a day expected to be over 78 or so, run the AC as needed all day.
    o On a day expected to be cooler, don’t run anything until the outside air cools off in the late afternoon, then run low or high speed fresh air through the house.
    o When using fresh air, automatically choose low or high speed based on the difference between desired and actual inside temp and the difference between inside and outside temp.
    I also want to control the attic roof fan at night with the outside and attic temperatures:
    o If the next day is expected to be hotter than 75, run the fan as long as the outside temperature is lower than attic temp.
    (Currently it runs on an analog thermal switch in the attic so it runs longer than it needs to and I have to climb up there to change the temp setting in spring and fall.)

    If your base OpenThermostat driver board doesn’t have enough 24v outputs to do all the above, I’d want to connect an expansion board.
    I also figured that the same main controller could control the sprinklers too, with an expansion board to activate the sprinkler lines.
    (That assumes the controller has enough capacity to accommodate all the firmware needed for OpenThermostat and OpenSprinkler.)

Viewing 21 posts - 1 through 21 (of 21 total)
  • You must be logged in to reply to this topic.

OpenSprinkler Forums Comments, Suggestions, Requests Wanted: OpenThermostat