Wireless thermometers transmit the measured temperature by radio to a central display unit. Several measuring units can be connected to such a unit outdoors or in different rooms of a building and transmit the measured values to them.
Wireless thermometers offer a relatively wide range of functions. They can be used to measure temperatures outdoors and indoors, and often humidity as well. They offer displays for the maximum and minimum values and can store the maximum and minimum daily values in an internal memory and compare them with new measured values. Depending on the design, wireless thermometers can collect readings from multiple sensors.
Temperature measurement is performed with temperature-sensitive sensors. The analog measured values are digitized to an AD converter and transmitted to the central measuring unit, where they are shown digitally on the display. As far as radio transmission is concerned, two frequency ranges in the sub- gigahertz range are available, namely the 433 MHz and 868 MHz bands. The signals can be modulated using various modulation methods such as frequencyshift keying or minimum shift keying( MSK).