Hi. I want to automate pulling a shade over a glass roof when the temperature inside is above a certain level AND the outside air temperature is higher than inside, AND there is direct sunshine on the glass (increasing the inside temperature further). If the outside air temperature is less than the inside temperature, e.g. in winter, then the direct sunlight is welcome and I want to keep the shade open....
I have shaded air temperature sensors below and above the glass and can evaluate those, but I don't have any good ideas for the sunshine (irradiation) sensing. A cloudy sky on a stinking hot day won't necessarily increase the air temperature under the glass, because the walls inside will reradiate to the outside too, so brightness may not be a good indicator. I thought about IR irradiation, but I don't actually know how much of that gets absorbed by clouds.
Maybe I should measure the wall temperature that gets hit by sunlight (and heated up) in a couple of locations and put that in the calculations?
Looking forward to opinions.
Cheers.
That's easiest option, maybe even better to attach matt black aluminum plate to temp sensor.