3. Sensors

A sensor is a device designed to measure some physical quantity in its environment.  An example might be a heat sensor that measures the temperature in a room or a pressure sensitive mat that detects someone walking over it.

temperature sensor
A temperature sensor is tucked away somewhere inside this fridge and its output is used by the display you see. The output could as easily be fed into a computer for further processing.

Once they have taken a reading or measurement, they might send that reading straight back to the computer or they may store it up and take a set of readings over time and send them back in a batch. 

This data is called an ‘input’. Whilst the sensor itself is producing an 'output'.

There are many different types of sensors, below is a table showing you a few of the most common ones:

Sensor Measures Where Used
Heat Temperature Living room for central heating system
Humidity Water vapour in the air Swimming pool, greenhouse
Infra-red Infra-red radiation e.g. body heat Security alarm systems
Light Light levels External security lights
PH Acid/alkali levels e.g. pH of soil Environmental experiments, river pollution
Pressure Pressure Burglar alarm systems, automatic doors
Smoke Smoke in the atmosphere Offices
Sound Levels of sound Security alarm systems
Tilt Angle of tilt Windows in security alarm system
Touch Detects if one object bumps into another Computer controlled robots

Challenge see if you can find out one extra fact on this topic that we haven't already told you

Click on this link: Sensors