Takes about 30 seconds after power-up to settle and begin detecting correctly.
Set the jumper to Range 2 - (max 2.5 secs)
For longer than 2.5 secs, select Range 3.
For reliable operation, use 3 x100nF capacitors between the motor connections and the case, to help suppress the high voltage spikes produced by emf.
The PIR produces a low output pulse when it detects a heat source and the LED comes on. This can be anything from 1 to 10 seconds depending on the heat source movement.
The low pulse triggers the Monostable which produces a timed high output pulse set by VR1. However if the PIR signal is active for longer than the timed period, then the monostable timing is ignored. If the timing is critical, then use the Circuit 2 option below.
This output from the monostable is connected to a relay with a transistor driver