Data logger is designed to observe and document alterations in conditions over a period. These devices can be standalone, single units, or can have multiple channels. Most standalone devices are battery-operated, enabling them to record data while on the move and for extended periods of time.

Data loggers utilize a microprocessor, an internal memory to store data, and a sensor for data collection. These are usually compact and battery-powered. Data loggers may be connected to a computer for data analysis and viewing using software, or can function as a self-contained device with a local interface or connect wirelessly to other devices.