Topics / Hardware / Sensors


Sensors are input devices that record data about the physical environment around it.

Sensors send data to a microprocessor (computer).  They do not make judgements, decisions or control any output devices.

There are many types of sensors used in a variety of household, commercial and industrial applications.

Advantages of using computer sensors

  • Sensors are reliable
  • Sensors are accurate
  • Sensors don’t get tired
  • Sensors work well in places where humans would rather not be

Common sensors and their applications

Magnetic Field Sensor

Detect changes in magnetic fields.
Can measure the strength and direction of a magnetic field.

  • Mobile phones
  • Anti-lock braking
  • Detection of cars at traffic lights
  • Reading magnetic ink characters on cheques

Motion (infra-red) Sensor

Detects movement / heat from objects.

  • Automatic doors
  • Burglar alarm systems
  • Gaming systems, inc accelerometer
  • Counting, e.g. people or cars

Temperature Sensor

Measures heat generated by an object or system. By measuring the change in heat, the sensor can detect changes in temperature.

  • Chemical process or reaction
  • Central heating (thermostat) / air-con
  • Greenhouses
  • Ovens, refrigerators and freezers

Sound Sensor

Measures the presence of sound.

  • Burglar alarm systems
  • Leak detection system

Moisture / Humidity Sensor

Moisture sensors measures the amount of moisture in a certain material whilst humidity sensors measure the amount of moisture in the air, along with its temperature.

  • Clothes dryer
  • Environmental control / greenhouse, air-con

Pressure Sensor

Measures pressure.

  • Burglar alarm systems
  • Traffic light controls
  • Chemical processes
  • Liquid through pipes

Gas Sensor

Detects the presence of gas in a certain area.

  • Pollution monitoring (river)
  • Greenhouse environments
  • Confined areas (space craft, aircraft)
  • Fish tanks / aquariums
  • Carbon monoxide alarms

Light Sensor

Can detect the ambient light level, meaning how bright or dark it is.

  • Controlling street lighting
  • Burglar alarms (beams of light)
  • Automatic doors
  • Greenhouse

pH Sensor

Measures how acidic or alkaline a material is.

  • Water treatment plants
  • Pollution monitoring (river)
  • Aquariums
  • Greenhouse

Our Input Devices page explains all about the other input devices that are not sensors.

Topics / Hardware / Sensors

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