A data logger is an electronic device that records data over time or in relation to location by means of its own or externally connected instruments and sensors. Almost all are based on microcontrollers. Monitor and record changes in conditions over time. They can be individual and independent units or consist of several channels. Most standalone units are battery-powered, allowing them to record while in transit and for extended periods of time.

Data loggers can monitor temperature, humidity, carbon dioxide, pH, pressure, voltage, current, and pulse – making them useful for a number of applications.