Northern Prairie Wildlife Research Center
Dave Ward and Kevin Lay, Sirtrack Limited, Private Bag 1403, Havelock North, New Zealand
Sirtrack Limited has added a remote temperature monitoring system to its range of wildlife tracking and telemetry products. The sensor is based on their highly reliable two-stage transmitter. Without battery or packaging it measures 24 x 7.4 x 7 mm and weighs less than 2.5 g. It has an accuracy of 0.25°C with a resolution of 0.1°C. The standard temperature range is -9.9 to +49.9°C but other temperature ranges are available. The unit uses a highly stable comparison circuit against which to reference the pulse period being determined by the temperature. A hand-held decoder measures the difference between the pulse rates and expresses it as a direct temperature reading. The system requires no calibration. The decoder plugs into the headphone jack of any good tracking receiver to give a direct LCD reading of the sensed temperature. The decoder is only 150 x 80 x 35mm and runs on a single 9-V alkaline battery. It has an RS232 port for computer logging of the temperature information. The comparison circuit pulses at 45 beats per minute so the transmitter can also be used for tracking and location work.