Design and Technology – Systems and control | e-Consult

Input Device: A light-dependent resistor (LDR) would be a suitable input device. An LDR's resistance changes depending on the amount of light falling on it. In a dark room, the LDR's resistance is high, and in a bright room, the resistance is low. The LDR provides an analogue electrical signal that represents the light level.

Process Device: A microcontroller, such as an Arduino or Raspberry Pi Pico, would be an appropriate process device. The microcontroller would read the analogue signal from the LDR using an analogue-to-digital converter (ADC). It would then compare this digital value to a pre-set threshold. If the light level is below the threshold (dark), the microcontroller will activate an output. If the light level is above the threshold (bright), the microcontroller will deactivate the output.

Output Device: A transistor or MOSFET would be used as an output device to control the LED lamp. The microcontroller would send a signal to the transistor/MOSFET, which would then switch the current flow to the LED lamp, turning it on or off. A resistor would be needed in series with the LED to limit the current and prevent damage.

Interaction: The LDR provides the input (light level). The microcontroller processes this input by converting it to a digital value and comparing it to a threshold. Based on the comparison, the microcontroller sends a signal to the transistor/MOSFET. The transistor/MOSFET then controls the power supplied to the LED lamp, resulting in the desired brightness control. A block diagram illustrating this interaction would be beneficial.