|The picture doesn't show "3" is weaker.|
After more than six months of uninterrupted operation, the tens of minutes display started loosing brightness and the decimal point burned out. In order to prolong its life I changed the code to switch off the display between 9.00 and 21.00 unless a large change in the incoming light is detected. In that case the time is shown for few seconds, and then off again.
Moreover during night hours the display is PWM'ed to reduce brightness, and heat dissipation is decreased as well.
The updated code is on github.