The DTM4000 is an inexpensive digital handheld multifunctional device for various sensors. The sensors are queried via a standard bus (I2C). A wide range of sensors is available for this purpose. Temperature, humidity (various inaccuracies) and brightness are currently realized. The sensors are pre-calibrated with a certain basic accuracy. New sensors are constantly being integrated. The device is powered by two AA cells. The display is shown on a two-line backlighted display. A USB interface is used for data acquisition and for setting parameters and calibration data of the sensors. For this purpose, they are equipped with an additional memory. Additional information can also be stored in a designated memory area. A corresponding PC program is available on the Internet. Current firmware versions can also be loaded via this interface if new sensors make this necessary. The sensors are detected automatically after switching on. The DTM4000 switches off after 3 minutes. This can be prevented by the software. If a USB cable is connected, the DTM4000 will not switch off, as the device is then supplied with power. The scope of delivery includes a standard temperature sensor and a transit case.