The role of sensors in control
Sensors are used to measure physical quantities such as temperature, light, pressure, sound, and humidity. They send signals to the Shorthand for central processing unit (CPU).. For example:
- a security alarm system may have an Radiation which transfers heat energy. Part of the electromagnetic spectrum with a longer wavelength than light waves but a shorter wavelength than radio waves. sensor which sends a signal when the beam is broken
- a heat sensitive sensor in the corner of a room may detect the presence of a person
- temperature sensors could be used to control the heating in a large building
- magnetic sensors are used to detect metal and can be placed in roads to monitor traffic flow
Other physical quantities that can be transmitted directly to the computer's processor include:
- rainfall/water levels
- radiation level
- pH level
- oxygen level
Analogue to digital conversion
Data such as pressure, light and temperature is Continuous data which can have a range of values.Values, typically letters or numbers.. Computers can only work with Information stored as discrete values usually represented as numbers. This contrasts with analogue data which is represented by continuous data, usually in waves. data.
An interface box or analogue to digital converter (ADC) is needed to convert the analogue data from the sensors into digital data the computer can process.