Sensors and feedback — Engineering, 11–13 years
A sensor measures something, such as light, temperature, distance or pressure. Feedback uses that measurement to adjust a system, helping it respond to changing conditions instead of simply following one fixed action.
A sensor lets a system notice
A sensor changes a physical condition into information a system can use. A light sensor detects brightness, a thermometer detects temperature and an ultrasonic sensor measures distance. The sensor does not decide the whole action; it supplies a reading for a controller or person to interpret.
Why use feedback?
A fixed instruction cannot know what has changed around it. A heater set to run for ten minutes may leave one room cold and another too warm. Feedback solves this by comparing a measurement with a target, then adjusting the action when the real condition is different.
A lamp that reacts to darkness
A garden lamp has a light sensor and a brightness target: switch on when the light level falls below 30 units. At 45 units in the afternoon, the controller keeps the lamp off. At 18 units after sunset, the reading is below 30, so the controller closes the circuit and turns the lamp on.
A sensor is not the decision
It is reasonable to call the sensor “the brain” because it is the part that notices the world. But a sensor only measures; another part uses the measurement. If a temperature sensor reads 22 °C, the system still needs a rule saying whether to heat, cool or do nothing.
Feedback in ordinary devices
Automatic doors use sensors to notice a person, washing machines measure conditions during a cycle, and a phone changes screen brightness when the surroundings change. Cars use many sensors to monitor speed, position and temperature. These systems are useful because they respond to the real situation, not just to a timer.
Keep exploring
Other languages
Loading MyLeoNes™…