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

Hardware Home Automation
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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.

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• 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?

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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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