Automatic A/C: Ambient sensor airflow?

[dj92]

Thanks for your answer

Originally Posted by CTScott

I have also done a couple of the conversions, so I can help if you have any issues.

OK, another issue is the solar sensor - also pretty expensive here (80€ or so) and hard to get, so I feel tempted to test my electronic skills
It is drawn like a diode, so I would assume that it is a photo diode.
Have you made any experiments with usual photo diodes (dark vs. light current etc.) or did you always use the original sensor?