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.

Sensors are reliable, accurate, and don’t get tired; working well in places where humans would rather not be.

Common sensors and their applications

Sensor Description Application
Magnetic Field 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) Detects movement / heat from objects. Automatic doors
Burglar alarm systems
Gaming systems, inc accelerometer
Counting, e.g. people or cars
Temperature 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
Ovens, refrigerators and freezers
Sound Measures the presence of sound. Burglar alarm systems
Leak detection system
Moisture / Humidity 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 Measures pressure. Burglar alarm systems
Traffic light controls
Chemical processes
Liquid through pipes
Gas 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 Can detect the ambient light level, meaning how bright or dark it is. Controlling street lighting
Burglar alarms (beams of light)
Automatic doors
pH Measures how acidic or alkaline a material is. Water treatment plants
Pollution monitoring (river)