ULTRASONIC

• What is an LED?

  A PN-junction diode that emits light
• How does an LED emit light?

  Through recombination of charge carriers
• What materials are used to make LEDs?

  Colorless semiconductor material
• What is the role of the P-type material in an LED?

  It is the surface where recombination occurs
• Where is the anode located in an LED?

  At the edge of the P-type material
• What is the function of the gold film in the LED cathode?

  It reflects light to the surface
• What are the advantages of LEDs?

  • Smaller size for high-density displays
  • Intensity controlled by current
  • Available in various colors
  • Fast switching time (<1 nanosecond)
  • Economical and reliable
  • Operate over wide temperature range
  • High efficiency with moderate power needs
• What is the typical voltage and current required for full brightness of an LED?

  1.2V and 20mA
• What are the disadvantages of LEDs?

  • Higher power consumption than LCDs
  • Higher cost
  • Not suitable for large displays
• What materials are needed to connect an LED to an Arduino?

  LED, 220Ω resistor, Arduino Uno R3
• How is the LED connected in the Arduino circuit?

  N-junction to GND, P-junction to resistor
• What function is used to set the LED to OUTPUT in Arduino?

  pinMode()
• What does the delay() function do in Arduino coding?

  Pauses the code for specified milliseconds
• What are the applications of LEDs?

  • Indicators and signs
  • Lighting solutions
  • Smart lighting systems
  • Non-visual applications
• What is an LDR?

  A light-dependent resistor
• How does the resistance of an LDR change?

  Resistance decreases as light increases
• What material is commonly used to make LDRs?

  Cadmium sulfide (CdS)
• What are the types of photoresistors?

  • Intrinsic Photoresistor: Uses un-doped materials
  • Extrinsic Photoresistor: Uses doped semiconductor materials
• What is the connection setup for an LDR with Arduino?

  LDR connected to 3.3V and pin A0
• What does the analogRead() function do in Arduino?

  Reads the value from an analog sensor
• How do ultrasonic sensors measure distance?

  By emitting sound waves and measuring echoes
• What are the main components of an ultrasonic sensor?

  Transmitter and receiver
• What is the formula to calculate distance using ultrasonic sensors?

  Distance = time * 0.034 / 2
• What are the applications of ultrasonic sensors?

  • Proximity sensors in vehicles
  • Robotic obstacle detection
  • Liquid level monitoring
  • Medical imaging
• What is Arduino?

  A microcontroller board for projects
• What is the purpose of Arduino hardware and software?

  To create interactive objects/environments
• What are the types of Arduino boards?

  • Arduino UNO R3
  • Arduino Mega
  • Arduino LilyPad
  • Arduino BT
  • Arduino Nano
  • Arduino Mini
• How can the Arduino UNO be powered?

  USB cable or barrel jack
• What is the recommended voltage for Arduino UNO?

  6-12 volts
• What does the GND pin on Arduino signify?

  Ground connection
• What is the function of PWM pins on Arduino?

  Simulate analog output using digital pins
• What is the purpose of the Arduino IDE?

  • Write and upload code to Arduino
  • Contains text editor and message area
  • Allows for serial communication with Arduino
• What is the baud rate for Serial communication in Arduino?

  9600
• What does the Serial.print() function do?

  Sends data to the serial monitor
• How does the ADC work in Arduino?

  Converts analog signals to digital values
• What is the maximum sample rate for Arduino's ADC?

  10,000 times a second
• What command is used to write an analog value to a pin?

  analogWrite(pin, value)
• What does the command Serial.begin() do?

  Initializes serial communication
• How is data transmitted in serial communication?

  As bits sent one after another
• What do the TX and RX LEDs indicate?

  Data transmission and reception