Dataloggers

Memory unit/data logger is an electronic device that records data using a built-in sensor or via external instruments and sensors. One of the main advantages of using it is the possibility of 24-hour automatic data collection.
These are usually small, portable, battery-powered units equipped with a microprocessor, internal memory for data storage and sensors. Some data loggers connect to a PC and use software to activate the data logger and view and analyse the collected data, while others have a local interface device (keyboard, LCD) and can be used as a stand-alone device.
Electronic data loggers have replaced traditional data loggers in many applications. After activation, they are usually left unattended to measure and record information during the monitoring period. This gives a comprehensive and accurate picture of controlled environmental conditions such as air temperature and relative humidity.
Source:Wikipedia 01/2021