New hardware model! Hestia Zero - your feedback please

After our successful crowd-funding campaign we got lots of feedback from newcomers…
We are investigating the addition (not replacement of existing) of a new hardware version and we want your feedback on this one.
As many people came from the openHAB land they already had an instance of openHAB running in their houses in more powerful computers with maybe already setup additional peripherals. This pushed them to the (right) direction of changing HestiaPi to a dummy extension to their main openHAB.
The result was a wall-mount remote relay with sensor and display.

Moving to this direction we are considering dropping the Raspberry Pi off our design and downgrading to an ESP based controller (something like an Arduino with WiFi).
A smaller non-touch OLED display with a rotary knob will enable the device to be physically controlled without having to pull your phone out every time you need to interact. A gentle beeper/buzzer speaker will add more ways to interact with the user if not present.

WiFi will still be the only networking capability with MQTT of course as it has always been so far. No change there. The thermostat would be 100% functional using it locally without anything else. Without even WiFi! But if you link it to your openHAB system, or any MQTT based system it will simply extend both ways your existing setup minimizing the modifications needed on your end.

The above changes are expected to make the unit smaller and cheaper. The less processing power needed and the fewer electronic components will dissipate less heat so passive cooling will be easier in a smaller and even more crowded case. The power supply block may even be swapped for a smaller one.

As we slowly move production of the original HestiaPi to China, we might as well do that too and offer production-line quality from the first batch with smaller costs.

So this is your turn… What do you think? Please share your thoughts but keep in mind the general direction we are trying to move to.

I could see myself falling in this user category and many other users that just want a thermostat. Imagine on top of that, a PWA you can load on your phone to directly interact with the thermostat over MQTT. You would get an icon on your home screen, and once you connect the app to your thermostat it saves those settings in the app’s localstorage.

In that scenario we would be talking about a simply WiFi-enabled thermostat but I can see your point.

In my case, I really appreciate the openHAB instance and the touch capabilities. It is true that openHAB is big, and I praise the work of @rlkoshak improving it.

But I consider the current setup a very interesting platform on which I can build other projects. I am finishing a couple of them that I will share soon!

was cooling really that much of an issue? It seems like you could just apply a static, constant adjustment to the temp reading to compensate.

Cooling, as in, too much heat stays in the case affecting the readings of the internal sensor. Not like the Pi overheats or something. This is the reason we move away the sensor with the internal cable.

I like the idea a lot and the use case you describe perfectly matches my personal use case. The HestiaPi is just smart enough to run autonomously but my main automation is running on a server somewhere else on my network.

Some additional things I like about using a microcontroller:

  • it’s not as big of a deal to keep up with updates; as a security engineer I’m still uncomfortable having a machine on my network that shouldn’t be updated periodically
  • near instant start/reboot times
  • smaller size
  • less power

The software will, of course, need to be completely rewritten and depending on which ESP model you choose you might run up against storage limits if you have to import too many libraries (MQTT, sensor, etc). Definitely pay attention to that as you choose the model.

We have completed similar hardware combination (libraries for WiFi manager, OLED screen, BME280 and rotary encoder) in other projects and had only managed to reach something like 40% of storage memory. We don’t expect the actual logic for the thermostat to cover that much more space but most definitely, if we decide to go that way, we will make a few prototypes and maybe share the designs here as beta for comments and feedback. Covid situation is not particularly helpful here…

I have some history with ESP/Xbee based devices as a thermostat. I built several over a two year period from 2016-2018. These devices sound great on paper, but in a live setting I found them unusable for a couple of reasons:

  • sensor driver support was pretty limited
  • if you live in a dense area the baud rate past 10-20 feet is an issue due to interference on 900kHz and below bands. You can still transmit/receive data, but the delay can be several seconds.
  • quality oversees manufacturers of ESPs and the like isn’t very good. I’d get 6-9 months out of a device before it die. Buying offical Xbee or particle boards is pricey.
  • wasn’t easy to support complex sensors (I2C, SPI, blutooth, one wire). It’s doable, but a lot of work.

In the end, I switched to the RPi Zero W when it was released. Why deal with ESPs when you can use standard Linux tooling and ecosystem. If cost is the primary reason for this idea, I’d drop the touchscreen and find some off the shelf stuff instead.

Working with the BME280 was pretty easy to be honest and WiFi connectivity has never been an issue. Of course we understand this changes from house to house.
About their life time, we have maybe 10 of them running 24/7 off mains and none has died (yet).
The price was only the result of this change. The main drive was the conclusion that a RaspberryPi is over-engineering for some people’s setup.

I repeat this is not about replacing HestiaPi. This is about offering an additional model for people who only want an extension of their existing smart home setup.

May be an idea…
A thermostats need to be autonomous from other system, and reliable over time.
OpenHab is quite interesting sw but too heavy for this HW, a solution like HestiaPi Touch IOThermostat may be a better solution for the Hestia HW.

You may take this sw and improve it, from my point of view need a better UI interface, functionality are good, and offer as alternative to OpenHab.
An evolution may be integrating it with Apple Homekit, Google Alexa.
To lower the HestiaPI cost you my use a smaller touch display (with luminosity control may be interesting), a display need always