[time-nuts] Environmental sensor recommendations

[Mark Sims]

Lady Heather has a very nice temperature control PID in it (designed by Warren Sarkisen).  It was originally designed to stabilize the temperature of a Thunderbolt GPSDO.  The standard Thunderbolt OCXO is rather temperature sensitive.  

The standard/simple implementation involves sticking the Thunderbolt in a cardboard box with some thermal mass and baffling.  Heather then PWMs a fan (at 1 Hz, using the serial port modem control signals and a DC solid state relay) to mix room temperature air into the box.   It can control the temperature readings to around 0.01C with long term RMS errors in the low microdegree range  (absolute accuracy depends upon the temp sensor).

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> I would suggest that if you are looking at taking temperature sensor data
and attempting to control some type of heating/cooling device that you
implement a PID loop for stability.