[RESOLVED] Building a Thermostat for 2 ac unit with openhab

Hello everyone,

I would want to build a thermostat for my ac unit.
I have one unit in my living room and one in the corridor.
I tried to hack the ac unit with an uart usb, but I failed.

So I imagine 2 ir controller to control the 2 ac unit, and an indoor thermometer (or several, to activate one or another ac unit)

Everything binded together with openhab and rules.

I would want a local system only, or if I need remote access, access it via openhab cloud.

Do you have any idea what I can buy to achieve that ?
I can diy if needed.

Thanks for your help.

• 1 x ESP32 - with OpenMQTTGateway on it
• 2 x Bluetooth Thermometers
• 2 x Tuya IR - Wifi Gateway, also with flashing OpenMQTTGateway onto both.

That would be my recommended setup.

All completely local with no cloud/internet connections needed. Both the thermometers through Bluetooth gateway and IR-Wifi gateways interface with openHAB via mqtt, letting you define your cooling rules as desired.

And the hardware costs are under $30 for it all.

Hope this helps.

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Thanks for you quick response.

Tuya ir seems perfect and cheap too.
The Bluetooth thermometer seems good too.
For the esp32, I imagine this is needed to read temperature?

My openhab instance is installed on old laptop with bluetooth on ubuntu 20, maybe I can use that to read temperature? What do you think?

Probably, if you implement the reverse engineered protocol for the thermometers on your Ubuntu system, which OpenMQTTGateway already has included, and/or if you install an alternative firmware onto them

which advertises their data without encryption.

Searching for “LYWSD03MMC” (the thermometers’ model number) on github does come up with several possibilities, e.g.

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Thanks for all this link.
I bought a spare esp32 just in case.

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