Flashing bathroom fan with ESP32E

ESPHome
1

Hi!

Accidentally broke my PAX Calima bathroom fan while cleaning it, and while tearing it down to fix it, discovered that there is an ESP32E embedded in the detachable motor unit. This device has Bluetooth enabled from factory and there are existing solutions to connect to it to HA via an ESP acting as a Bluetooth bridge.

I'm curious about exploring the possibility of skipping the middle man here and running ESPHome right inside the motor unit. I'm thinking aside from exposing the fan control, moisture- and light sensors, it might also be possible to activate the wifi chip and extend the possible use cases.

The PCB has what I believe is an exposed serial programming port, shining a bright light on the edge of the PCB one can guesstimate the locations of the GND (the one connected to the gnd-plane) and tx/rx pins (the two next to each other)

I am not finding much info on this variant of ESP32 in a ESPHome context however.

  • Can somebody verify that ESPHome is compatible with ESP32E?

  • Does anybody have any insight in what the pinout of the serial interface might be, or how I might go about determining it?

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2

Yes, it's just common
esp32:
variant: esp32

You need to inspect all principal components on pcb, find good magnifying glass...

1 Like
3

Brilliant, Thanks! I'll move on then. Now to find my scope...

4

You could examine the pinout datasheet for the ESP32 and verify with a multimeter which pin on the chip is connected to which pin on the interface board.

Sadly my screen resolution does not bring up the photos in enough clarity to recognise the individual part numbers.

You could examine the other chips and check their pinout to determine their functionality as well.

Is the fan speed controlled, or just on/off?

What pins go to the sensor? Is it a DHT11/22?

Reverse engineering can be fun and rewarding when you finally crack it.