The DHT21 sensors used in the “Beelogger” are capacitive sensors used in modern electronic absorption hygrometers. This type of sensor uses a hygroscopic layer as dielectric between the two electrodes of a capacitor. The absorption of moisture in the dielectric changes its properties and so the electrical capacity of the sensor.
The first self-made data loggers (beelogger solar SD) according to the instructions of Thorsten Gurzan (www.beelogger.de) go into operation!
- Waterproof housing, suitable for outdoor use, with screw-on device
Each measuring station contains 3 combined sensors for humidity and temperature, with an accuracy of ±0.5°C or ±3%.
- Equipped with a real-time clock, i. e. the data is written with a time stamp. This real-time clock also records the temperature in the housing.