A data logger is a machine equipped with a sensor, an electronic chip, and internal memory designed to record data at regular intervals for detailed analysis in the future. The sensor measures the physical phenomena or the source of data. The data collected by the sensor is converted into electronic signals by the chip, which then proceeds to store the information in its internal memory. A data interface mechanism allows the logged data to be accessed for analysis and interpretation.

A data logger is a versatile device that can be used for a wide range of reasons. From assessing the amount of sunlight or rain received by a city or region to the average temperature of the cold storage vehicle throughout its journey across the country—a data logger facilitates automatic collection of data at periodic intervals without any reliability or performance issues. Two commonly-used data loggers are devices that measure and log temperature and humidity.