Unfortunately the design of the basic PIR can not discriminate between different heat sources. It reacts to changes in the heat signatures in the field of its view. If they are static it remains passive and if it detects a change it reports that change. One would need some sort of temperature discriminator that responded only to temperatures in the range of human body temp to be able to see humans and ignore animals of other body temps and objects.
Unfortunately the design of the basic PIR can not discriminate between different heat sources. It reacts to changes in the heat signatures in the field of its view. If they are static it remains passive and if it detects a change it reports that change. One would need some sort of temperature discriminator that responded only to temperatures in the range of human body temp to be able to see humans and ignore animals of other body temps and objects.
