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2. Electronics ⚡
2. Electronics ⚡
This allows your product to sense the environment and react. You’ll work with Input components (like light sensors or switches), Processors (like integrated circuits), and Output components (like LEDs, buzzers, or motors). If you were designing a smart bedside lamp that turns on when it gets dark, you would need to understand how a Light Dependent Resistor (LDR) works in a circuit.
Electronic Questions
Electronic Questions
Scenario: The Smart School Locker System
Scenario: The Smart School Locker System
A school is considering a new design for student lockers that integrates electronic features to improve security and accessibility. The new 'Smart Locker' system uses a keypad for entry, an internal light to help students find their items, and an alarm system to alert staff of forced entry.
The system is powered by a 9V DC power supply. The following components are used:
A Light Dependent Resistor (LDR) to detect darkness inside the locker.
A red Light Emitting Diode (LED) to indicate a security alert.
A microcontroller to process signals.
A keypad.
A resistor.
A buzzer.
Question:
(a) State the function of the Light Dependent Resistor (LDR) in this Smart School Locker system. [2]
(b) Explain why a resistor is connected in series with the red LED. [2]
(c) Describe how the LDR and the microcontroller work together to automatically switch on the internal light when the locker door is closed. [4]
(d) Name the type of signal the LDR sends to the microcontroller. [1]
(e) Sketch a circuit diagram that shows how the red LED and the buzzer are connected to the microcontroller to function as a security alarm. Annotate your drawing to show the input and output components. [4]
(f) State one input and one output component used in this system, other than those mentioned in part (e). [2]
Input:
Output:
(g) Explain how the buzzer, as an output component, can effectively alert staff of a forced entry. [2]
(h) A student enters the correct password on the keypad. Name the type of output signal that the keypad sends to the microcontroller to unlock the locker. [1]
Electronic Questions
Electronic Questions
Answer Key:
Answer Key:
The Smart School Locker System.
The Smart School Locker System.
(a) State the function of the Light Dependent Resistor (LDR) in this Smart School Locker system. [2]
(a) State the function of the Light Dependent Resistor (LDR) in this Smart School Locker system. [2]
The LDR acts as a sensor to detect the level of light inside the locker. When the locker door is closed, the light level decreases, causing the LDR's resistance to change. This change in resistance is detected by the microcontroller.
(b) Explain why a resistor is connected in series with the red LED. [2]
(b) Explain why a resistor is connected in series with the red LED. [2]
A resistor is connected in series with the red LED to limit the amount of current flowing through the LED. This is crucial because an LED is a current-driven device. Without a resistor, the LED would draw too much current from the power source, causing it to burn out or be damaged.
(c) Describe how the LDR and the microcontroller work together to automatically switch on the internal light when the locker door is closed. [4]
(c) Describe how the LDR and the microcontroller work together to automatically switch on the internal light when the locker door is closed. [4]
When the locker door is open, light enters, and the LDR's resistance is low.
When the door is closed, the locker becomes dark. This darkness causes the LDR's resistance to increase significantly.
The microcontroller is programmed to monitor the voltage across the LDR. When the resistance of the LDR increases above a specific threshold (due to darkness), the microcontroller detects a change in voltage.
The microcontroller then processes this change as a signal to activate the output, which is the internal light, switching it on automatically.
(d) Name the type of signal the LDR sends to the microcontroller. [1]
(d) Name the type of signal the LDR sends to the microcontroller. [1]
Analog signal.
(e) Sketch a circuit diagram that shows how the red LED and the buzzer are connected to the microcontroller to function as a security alarm. Annotate your drawing to show the input and output components. [4]
(e) Sketch a circuit diagram that shows how the red LED and the buzzer are connected to the microcontroller to function as a security alarm. Annotate your drawing to show the input and output components. [4]
(f) State one input and one output component used in this system, other than those mentioned in part (e). [2]
(f) State one input and one output component used in this system, other than those mentioned in part (e). [2]
Input: Keypad, LDR
Output: Internal light
(g) Explain how the buzzer, as an output component, can effectively alert staff of a forced entry. [2]
(g) Explain how the buzzer, as an output component, can effectively alert staff of a forced entry. [2]
The buzzer is an audible output component. When the microcontroller detects a forced entry (e.g., from a sensor), it sends a signal to the buzzer. The buzzer then produces a loud sound, which is easily heard by staff, drawing their attention to the locker and alerting them to the security breach.
(h) A student enters the correct password on the keypad. Name the type of output signal that the keypad sends to the microcontroller to unlock the locker. [1]
(h) A student enters the correct password on the keypad. Name the type of output signal that the keypad sends to the microcontroller to unlock the locker. [1]
Digital signal.
Disclaimer :
I can make mistakes, so double-check it with textbook, past year papers and other online resources.
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