Input Devices
Definition
Input
What is put into a system
- Input devices detect changes in the environment and send signals into an electronic system.
- They act as the system’s “senses,” triggering a process or output.
Types of Input Devices
- Analogue Input Devices
- Produce continuous signals that vary over time.
- Examples: Temperature sensors, light sensors.
- Digital Input Devices
- Produce discrete signals, often in the form of binary data (0s and 1s).
- Examples: Switches, digital microphones.
Note
Analogue signals are continuous and can take any value within a range, while digital signals are discrete and represent data in binary form.
Switches
- Purpose: Turn a circuit on or off manually or mechanically.
- Functionality:
- When a switch is closed, it completes the circuit, allowing current to flow.
- When open, it breaks the circuit, stopping the flow of current.
- Examples: Push buttons, toggle switches, reed switches (activated by magnets).
- Signal Type: Digital (just two states – ON/OFF).
Sensors
Definition
Sensor
An electronic input device that detects or measures physical changes in the environment, such as light, temperature, or motion, and converts them into electrical signals.
| Sensor Type | Detects | Example Use | Signal Type |
|---|---|---|---|
| Light Sensor (LDR) | Light level | Auto night lights, phone brightness | Analogue |
| Temperature Sensor | Heat changes | Thermostats, smart fridges | Analogue |
| Humidity Sensor | Moisture in air | Weather stations, indoor air quality systems | Analogue |
| Sound Sensor | Volume or noise level | Voice-activated systems | Analogue |
| PIR Sensor | Motion detection | Security lights, alarms | Digital |
Example
An LDR in a streetlight system detects decreasing light levels at dusk, triggering the light to turn on.
Note
Humidity sensors are crucial in agriculture, where maintaining optimal moisture levels can significantly impact crop yield.
