18. Sensors

Sensors are used to detect physical quantities outside a computer such as light, temperature and pressure.

They collect data automatically and usually at regular intervals. This data can either be transmitted immediately to the computer or it can be stored for a period of time and a batch of readings sent in one go.

In order to process input from sensors, a device called an 'Analogue to Digital Converter' (ADC) must be connected between the computer and the sensor. This device converts the analogue signals from the sensors to digital data that the computer can process.

The photo opposite shows the Rasberry Pi which is a single board computer and one of the things it can do is take in and process data from external sensors connected to it.