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2026

  • 6 min read

ESPHome on Tuya IR-Remote

A while back I bought a Tuya IR-Remote to control my AV equipment using Home Assistant. I've read that it was possible to flash ESPHome, but with so many variants available, it was hard to be sure. Since these units are not very expensive, I gave it a shot and ordered the following Tuya Wifi Smart IR remote.

Inspection

The unit arrived in a small cardboard box as shown below. In the box there was a small manual, a USB-C cable and the IR-Remote. As can be seen on the back of the box, the full model name is WIFI Smart IR Remote Controller (IRC03). However, this doesn't tell us if it is possible to flash ESPHome.

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Box front.

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Box back.

  • 6 min read

Reverse engineering modbus protocol

Recently, I started an effort to integrate the heat recovery ventilation (HRV) system into my Home Assistant setup. The house is equipped with a Zehnder ComfoAir E300, but after an extensive search I couldn't find any existing integrations for this particular model. I did however found an issue hinting at an undocumented connector that was connected to a level shifter, suggesting a serial interface was available.

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Schematic showing the IC connected to C3.

I disassembled the device, probed the PCB with a multimeter and followed the traces from the connector. The result can be seen in the figure above.