Actron Aircon / ESP32 Controller Help

ESPHome
122

Hi,
I ended up using:

  1. BC549 (has low noise than BC548).
  2. Did not use any external DAC, just the native ESP32 DAC pin GPIO26 (GPIO25 would have worked also).
  3. Added a DC to DC buck converter to lower voltage from 19v(AirCon) to 5v (ESP32), so no external power adaptor. https://www.aliexpress.com/item/1005004587366838.html
  4. Added a 16V 4700uF capacitor on the DC Buck converter to stabilise voltage. (Between ground and Vout.)

So far so good. Very stable and no drift of any sort.

123

Do you have a copy of the code? As well as a schematic?

124

Thanks for confirming. I am receiving drift as temperature changes. It sounds like this is much less an issue on the BC549?

125

Code here. GitHub - skenderh/AirconKeypad (I just uploaded it). Considering that we are in winter now, not much of temp change, not sure how it will go during summer, as the device is in the attic. So far stable anyway.

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126

Thanks. I’m currently getting drift between morning and afternoon once the house heats up a bit. It’s also in an enclosure in the roof space. I will get a DS18b20 also and add it to my circuit so I can try compensate later if need be.

127

Just ordered the parts to try this on my Accent Air system (It uses the same wall controller as the Actron).

Looks like a few people are having issues with the transistor drift with temperature.

Would it be possible to program the unit with a set value from the transistor eg; then program all of the key presses as a percentage of that set value. Then every press would be a function of the transistors moving output.

Or is the temperature drift non-linear?