Data-loggers

A relatively recent innovation, the data-logger is rapidly growing in popularity among librarians and archivists because of its cost (lower than the cost of a hygrothermograph), convenience, and adaptability. Data-loggers range from simple battery-operated devices that register temperature and humidity and must be regularly downloaded into a computer to sophisticated instruments that are connected to the Internet and can monitor factors such as temperature, humidity, light intensity, and pollutants.