Understanding Input Devices
Definition
Input device
Hardware components that capture data from the environment and convert it into a form that a computer system can process
Input devices play a crucial role in control systems by providing the necessary data for decision-making and automation.
They can be categorised as:
- Manual Data Entry
- Devices: Keyboard, mouse, joystick, touch screen, touch pad
- Example Use: Adding client or book records in a library
- Direct Data Entry
- Devices: OCR/OMR scanners, MICR reader, barcode scanner
- Example Use: Lending a book, locating borrower details
- Automatic Data Entry
- Devices: Sensors (temperature, sound, pressure, light, etc.)
- Example Use: Controlling the temperature in the library
In control systems, input devices are often sensors that monitor specific physical properties, such as temperature, motion, or pressure because of their automatic nature.
Choosing the Right Input Device
When selecting an input device for a specific situation, consider the following factors:
- Accuracy: How precisely the device can measure the intended quantity.
- Range: The limits within which the device can operate effectively.
- Resolution: The smallest change the device can detect.
- Cost: The price of the device, including installation and maintenance.
- Durability: The device's ability to withstand environmental conditions.
- Compatibility: The degree to which the device integrates with existing systems.
- Always consider the specific requirements of the application when choosing an input device.
- A device that works well in one scenario may be unsuitable in another.
Input Devices Types in Control Systems
| Device Type | Examples / Subtypes | Common Applications | Accuracy | Range | Cost |
|---|---|---|---|---|---|
| Motion Sensors | Infrared (IR), Ultrasonic, Microwave | Automatic doors, security systems, lighting | High | Varies (microwave > ultrasonic) | IR is most affordable |
| Temperature Sensors | Thermistors, Thermocouples, Infrared | Smart heating, refrigeration, industrial | Critical | Must match environment | Moderate to high |
| Pressure Sensors | Piezoelectric, Capacitive, Strain Gauge | Automotive systems, machinery, electronics | Essential | Must fit pressure levels | Moderate to high |
| Proximity Sensors | Inductive, Capacitive, Ultrasonic | Robotics, manufacturing, vehicles | Crucial for safety | Ultrasonic > Inductive | nductive typically more expensive |
| Human Interaction Device (HID) Devices | Keyboard, Mouse, Touchscreen | User input, data entry | Important | N/A | Varies; generally affordable |
| Specialized Devices | Barcode scanners, RFID readers | Retail systems, inventory, access control | Important | Depends on technology (e.g., RFID range) | Moderate to high |
Ethical and Practical Considerations
- Privacy: Devices like cameras and microphones may raise privacy concerns.
- Cost vs. Benefit: Balance the cost of the device with its impact on efficiency and safety.
