I've been using a virtual thermostat with a fireplace, which also has a virtual sensor, and a Shelly Relay to turn the fireplace on and off.
But, I want to put something on the wall for it. My first thought was some eInk battery powered dashboard with the dashboard virtual controller. Basically just a 1x2 dashboard device, but that can run for months off a battery, so I was thinking e-Ink. But, then I thought that's ridiculously complicated, no one has any low-power e-ink tiny dashboards devices, right?
Then I thought what if just buy a battery powered thermostat? But, it would have to be zWave or Zigbee to send a signal to the Hubitat, since sending the API call to the Shelly over Wifi would take too much energy.
So, anyone know any low power battery operated device I can stick to my wall? To control the fireplace via a thermostat or virtual thermostat?
If simple zwave/zigbee/wifi buttons are not an option:
The first thing that came to my mind is to simply use some tablet in a kiosk mode routed to a custom hubitat dashboard.. Tho it is not so long lasting on internal battery.. without periodic charges.
Then if there is any e-ink book reader (probably on android OS) it might actually do the trick. A price tag could be really conserning..
Another option is to use some Shelly BLU button (directly connecting it to your mentioned Shelly module). Can be fully local. Will need tinkering with shelly scripts to get it to work fully locally.
That sounds similar to what do with my heat. My three heating zones are controlled by custom virtual thermostats, but I use my Honeywell T6 Zwave thermostats as wall controllers for them.
Any change on the physical thermostat gets synced to the virtual thermo, for mode, cooling setpoint, and heating setpoint. I also sync the other way, so if I change mode or temp setting on the virtual, it syncs to the physical T6s. This requires a check that the current setting is not already what it is being set to, to avoid an infinite loop of them both updating each other forever to the same value.
The T6 can run on batteries, or 24VAC. I only use the batteries as a backup since I have a C-wire, so I'm not sure how long they last when only using batteries. They take 4 AA.
I was looking at an Amazon Fire, I could put it on the side table near the fireplace, where there’s power. Then it wouldn’t need to be a battery powered device. Is that still the easiest way for a cheap dashboard? In the past I’ve been able to deploy old iPads as wall mounted dashboards, but they haven’t done well with the power/battery/software update. So maybe a Fire would be better.
Or is it feasible to deploy an old IPhone in Kiosk mode?
No, that is one of the main reasons I am using virtual thermostats. The temp from the T6s is horrible. It rounds to whole digits F from a Celsius conversion, so in regular mode it will not even display some whole digit temps. It will display all F temps if it is in Zwave temp mode that provides .1 degree readings, but I graphed that and it is even worse than standard mode, and the temps jump at least a whole degrees at a time, even though it displays in tenths to Zwave. The Zwave temp mode is also more imprecise as far as reporting the real temperature.
That is why I use Zigbee temp sensors and virtual thermostats. I have the temp sensors reporting on .05 degree change thanks to the kossev drivers, which is important to react quick enough to anticipate needing heat, or when to turn it off.
The T6 is also not good at regulating consistent temperature, it swings a lot using some algorithm, and I tried all the cycles per hour settings and none of them helped the fact that temps swing 2-3 "actual" degrees, while the thermostat always reports on the screen that it is right on temp.
I wrote an anticipating cycling thermostat driver now that now runs my heat (and AC) within .5 degrees from setpoint. The T6s make great consoles.
There is a controller app that goes with the driver for each thermostat. It syncs the temp to the thermostats, and it subscribes to the operating state of the virtual thermostats to run the relays.
The virtual thermostat doesn't need to know if the valve is on or off, that is all on the controller to react to the driver's operating state. My controller also does the syncing for temp from the sensors, and the sync between the thermostats, and it even uses the temperature offset of the T6 to force it to read the rounded value of the Zigbee temp sensors on the T6 screen. It is very handy that the community T6 driver has a temp offset command, and attribute, so I can change the temp on the thermostat using the offset, and get the current offset value back.
Actually, I did a post on it at the time. Current code is not using slope calculations or any of that more complex stuff I tried. I now just use outside temp to adjust the cycle time by a coefficient in the settings, set for each area.
