[ATM] IR pyroelectric detetors

[David Nicholls]

Having several surplus defective IR movement detectors (which disgraced 
themselves by triggering false alarms), I was wondering if anyone has 
used the pyroelectric sensor from a movement detector as a way of 
measuring mirror temperature for a cooling fan controller?

The sensor type in at least two of the movement detectors is a P4488-02 
made by Hamamatsu. It has a small rectangular Germanium window in a TO5 
can.   A thorough analysis of IR detectors and circuits is online at 
<http://sales.hamamatsu.com/assets/applications/SSD/Characteristics_and_use_of_infrared_detectors.pdf>

Should be possible to use one or more of these sensors in a fan speed 
controller, but no sense in reinventing the wheel if someone has already 
done it.

DN
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David Nicholls
http://www.dcnicholls.com