I have the PIR sensor Rev. B 555-28027:
I understand from the information sheet that it takes 40 seconds upon startup to determine a baseline reading on the IR flux into the sensor, then uses that to determine a significant change to indicate motion. I have a few questions:
1. What happens if the ambient lighting condition changes, slowly, or rapidly to a new overall level?
2. Is a new baseline taken if the background level changes, ie. does the sensor somehow adapt to the new ambient conditions?
3. If so how much and how rapidly does it adapt?
4. Does it adapt to the background rate of change of IR or the actual IR level?