The smart thermostat has become in a way the public face of the Internet of Things. It’s a demonstration that technological uptake by the general public is driven not by how clever the technology is, but by how much use they can see in it. A fridge that offers your recipes or orders more eggs may be a very neat idea, but at street level a device allowing you to turn your heating on at home before you leave work is much cooler. Products like Nest or Hive have started to become part of normal suburban life.
There is no reason though for an IoT thermostat to be a commercial product like the two mentioned. Our subject today demonstrates this; SST is a Wi-Fi smart thermostat using an ESP8266 that can be controlled by an app, thanks to its use of the open-source Souliss IoT Framework.
The build is very well finished, with PCBs, colour display and other components in a neat 3D-printed box. It’s a project that you could put in front of an end-user, it’s finished to such a high standard. Physical entity files are available from the hackaday.io page linked above, while its firmware is available in a GitHub repository. THere is a video showing some of the device’s capabilities, which we’ve put below the break.
If this is a subject about which you’d like to know more, we’d like to point you at a couple of previous articles, one a simple ESP8266 thermostat, and the other a guide to rooting the Nest.
Now all I need is a “C” wire to power it.
If your system lacks a “C” wire, you can usually add one in at the control panel for your AC/heater. Most systems, even very old ones, can be retrofitted. Venstar makes an add-a-wire product that takes 4 wire systems and converts to 5 wire for smart thermostats. ~US$30.
http://a.co/17zf3CN
Companies also sell 24VAC transformers that you can wire to R and C to power the thermostat even if the furnace doesn’t have a C wire (or you have no way to run an extra wire – as is the case in my current rental)
You can also remix the design to use two AA batteries or one 9V battery and a regulator. Since the display only comes on when needed, and the ESP8266 conserves power when using WiFi, it would be a good choice.
I would go this route, and leech off power to recharge when the relay isn’t actuated. I would hope the duty cycle leans in favour of the off state…
Oh, and you’d have to use a latching/impulse relay
Needs OpenTHERM support for Europe and for modulation of heating systems. Then we’ve got ourselves an awesome solution :)
“turn your heating on at home before you leave work is much cooler.”
Shouldn’t that be much hotter? (Or did you mean turning on the air conditioner?)
If you plan go on batteries I would suggest to use BME280 or HTU21D instead of DHT22, faster reading and lower current usage they have also smaller size.
Anything is better than crappy DHTxx: http://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_many.html
Wonder how someone can trust this kind of crap outside arduino “hacking”?
Your link shows that they’re all accurate to within half a degree C. These sensors are $3. What are you talking about?
“There is no reason though for an IoT thermostat to be a commercial product like the two mentioned.”
There are already a few commercial options available. In Germany they are actually pretty well known. Just to name a few: Homematic, MAX! (they are all german products).
And since I am renting and the WAF (Wife Acceptance Factor) needs to be pretty high, I just installed two of them and set a weekly/daily program. This build seems very much inspired from what the MAX! system does.
For the DIY oriented among us, they also offer the IoT products as half-build pieces/assembly kit (for a cheaper price, about 5-10€ cheaper) and one has to build the whole thing.
I think that the success it had in Germany (don’t know about other places) means that there are actually enough reasons for such a product to exist commercially.
I think you may have misunderstood. What he is saying is that internet enabled thermostats don’t HAVE to be commercial products. Smart thermostats are a huge market and any hardware store is full of them. Building your own is much more interesting though.
Cool and probably cheaper option than our (RasPi based touch screen) new HestiaPi :)
I can assure you though open source and commercial can go along just fine ;)
Well done guys!
Would love to try this out! Never heard of this, only the commercial products like Nest and Ecobee.