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
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
- Greenhouses
- 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
- Greenhouse
pH
Measures how acidic or alkaline a material is.
- Water treatment plants
- Pollution monitoring (river)
- Aquariums
- Greenhouse
