Monitoring the Temperature
Inside the W1FY Freezer

The W1FY freezer was designed to keep the equipment warm in the winter, despite residing in an unheated location. It does a great job!

The next challenge was to find a way for the remote sysops to monitor the inside temperature. Our concern now became the summer.

Peter, KA1AXY, found a circuit board that contains a thermal sensor which can be read from the parallel port of a computer. Peter worked with Charlie, NC1N, to develop an interface that would allow PacketCluster to read the temperature. Peter implemented the sensor interrogation in a C program. Charlie wrote several more programs and scripts to allow the node to trigger interrogation at the appropriate times, to save or post the output, and to manage the SHOW/THERM file area.

The sensor is protected by a plastic box chosen for cheapness and good air flow. It ain't pretty, but nobody can see it in the cabinet, anyway! The circuit board is actually 1/2 the length of the box.

W1FY Interior Thermal Sensor

General users can access the thermal data by typing SHOW/THERM. This lists a set of daily temperature files, named after the date. Each file contains 23 hourly readings. It is posted to the file area at approximately 2302 UTC each day. A specific file can be downloaded with the command TYPE/THERM <filename>.

Sysops also receive automatic hourly readings on their consoles, and can interrogate the sensor on demand.

[PacketCluster Home Page ] Last Update: 23 May 1999