Comment by p1mrx | Hacker News Reader

Comment by p1mrx | Hacker News Reader

I just got some new air conditioners for the shelter-in-place summer, and I'd like to control them from a central thermostat, but it's annoying that the remote sends "next mode" or "toggle power", with no way to jump to a known state.

The cool/fan/dehumidify/heat mode is indicated with a vertical column of LEDs (EdgeStar AP14001HS), so I can probably stick a photocell at the top, and have a program repeatedly send "mode" while watching the brightness level, to deduce the state and stop on the correct one. The fan speed uses a different column of LEDs, but stopping on "dehumidify" forces the fan to low. The temperature can be set blindly because it stops at the minimum/maximum value.

I haven't actually tried to build anything yet, but it at least seems possible using a Raspberry Pi with 1 analog photocell and 1 IR transmitter.

Unless you really want to dive into building it for fun, check out the Sensibo Sky. If your unit is compatible, I think that's the way to go. I honestly think they're slightly overpriced for what they are, even on sale, but I've also bought 4 and have been very happy.

Basically you get all the control/features you want by app or API, based on the unit's thermostat and hygrometer. Remote control, scheduling, auto on/off based on your location if you want that, and the big thing for me: programmable event control with any settings (cool/dry/fan at X degrees and Y strength/angle).

I mostly use the temperature based on/off programability because that feels the most like a traditional central air to me. I usually do: "when temperature is >24C, turn unit on to cool 20C medium fan strength" and "when temperature is <23C, turn unit off".

How does Sensibo handle the state synchronization problem? I would happily pay for something that works, but throwing state-dependent IR codes into the void is a recipe for pain.

Monitoring the current draw may give some clues

We make a smart thermostat for minisplits using IR (flair.co/products/puck). We have solved for state problems but some brands were such a PITA!

According to [1], Flair doesn't work with stateless remotes, and EdgeStar is not on the manufacturer list. My units are dual-hose portables, because I can't put equipment outside the building.

[1] https://support.flair.co/hc/en-us/articles/360004153852-Can-...

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