Do I have to build my own touchscreen thermostat?

[email protected]

"Smartknob View"

Sabata

Tape a raspberry pi to the wall with some relays and a temperature sensor dangling and call it a day. Anything else is spying on you.

[email protected]

Except thermostats. You literally could do it with a Raspberry Pi, some 24V relays and a temperature sensors. Thermostats are not that hard.

[email protected]

Inputs and outputs mapping sure is hard /s

[email protected]

Program it in increments?

My house has a lot of thermal mass. In the morning when the temperature comes up, it tends to overshoot after working hard to heat all that thermal mass. However I found it much more comfortable to add an increment: half an hour at a degree colder than I want. Now it can heat all that thermal mass while overheating the air is just playing into my hands

[email protected]

I’ve got it programmed in increments of a half a degree per hour. The thing still goes into panic mode.

[email protected]

It’s actually surprising that we expect so much from a smart thermostat. Wouldn’t it be far smarter to sell a dumb thermostat on a local iot network and put the smarts in your automation hub? People who want the extra functionality would be good with that and people who don’t would appreciate saving the money

[email protected]

If my choices are a z-wave/zigbee thermostat that connects to my HomeAssistant instance and a Raspberry Pi that I have to maintain, I'll pick the z-wave one (and I did, 10 years ago. It's been rock solid.)

For my smart devices I prefer devices that can't send information over the internet no matter what. I don't want to worry about my thermostat mining bitcoin for some dude in China.

[email protected]

A smart thermostat is the only smart device I own (ecobee). I figure it actually is better than something I could design in a week so it seemed worth it. Do you know of an actually competitive open hardware/open source solution?

[email protected]

Smart thermostats do way more than just set the temperature: that's table stakes. Off the top of my head the ecobee will:

Set the temperature also taking the room's humidity into account
Communicate with sensors throughout your house
Can change things via the Internet in case you accidentally forget to set it to a better temperature when you'll be gone for a few days
Tweak your schedule based on demand

I'm probably missing things, but they're actually pretty useful, and I'm someone who thinks most IoT is shit.

[email protected]

Well that's not quite true.

I have some z-wave thermostats, which I know do not talk to the Internet, just a local system with a zwave dongle.

For a relative, recently set up a similar setup, but with a homekit thermostat. Similar deal, though it really really wanted to connect to a cloud server and you kind of had to trick it to a non apple homekit setup. The follow on model from that brand did drop homekit support, presumably because they wanted to force their cloud servers, which became required for any advanced functionally.

There are ways to get automation friendly devices without a cloud connected requirement, though admittedly you have to be paying pretty close attention. Generally offerings for business are more likely to be locally workable, but that's hardly a given either

[email protected]

As the other poster said, both Zigbee and Zwave devices do not talk to the Internet. They can't even connect to your Wi-Fi anyway. They need to connect to a device that acts as a router but specifically for Zigbee or Zwave, usually called a Hub or Coordinator.

There's many different hubs around. Many commercial ones do indeed connect directly to the WiFi and therefore internet. But nothing is stopping you from buying a USB Dongle Hub with open source firmware and plugging it into a Raspberry Pi, if you want to eliminate the potential spying.

The Zigbee and Zwave networks inherently cannot communicate with the Internet. So the only risk of spying is if you installed something in the Raspberry that spies on you.

Both Philips Hue and IKEA Trådfri and many other vendors simply use Zigbee, which means you can bring your own Hub and completely eliminate the risk of spying.

[email protected]

Which are all things you can easily do with an RPi and some simple python. My response was to OP stating that embedded systems are hard.

If you’re using a specific embedded system and want to make it pretty, sure that could pose some issues, but if you want to make something functional that matches what a smart thermostat can do, there’s not much behind it.

Sabata

Do you trust every device you buy without question?

[email protected]

Noting ESP specific to my knowledge, but there is a home assistant community.

[email protected]

my high efficiency HVAC unit would like a word with you.

what you're saying is basically you can replace anything with a RPI. yes, in theory, you are correct. but, unfortunately for you, there are nuances that you didn't take into account. such as, startup/shutdown procedures, cool down cycles, heat pumps, dual compression ac units, etc.

[email protected]

Nope, but I trust the ones that lack the hardware for dialing home.

[email protected]

Alright I'll check it out. Tnx:)

[email protected]

All of that is handled by the HVAC (if there's anything to handle) and not the thermostat

Thermostats can be (and most often are) a bimetallic strip that bends one way as it cools and bends the other way as it warms, and that flips some switches that you set for temperature ranges which then demands cool or hot from your hvac

[email protected]

Raspi is overkill. Mine runs off an esp32 using code I wrote in Arduino. The web interface takes up more space than the code.
Only reason it's an esp32 instead of an Atmega 328p is the wifi support