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Questions and Answers
What is the minimum distance that the HC-SR04 sensor can measure?
What is the minimum distance that the HC-SR04 sensor can measure?
Which pin on the HC-SR04 sends the ultrasonic pulse?
Which pin on the HC-SR04 sends the ultrasonic pulse?
What operating voltage is required for the HC-SR04 sensor?
What operating voltage is required for the HC-SR04 sensor?
What is the maximum measuring range of the HC-SR04 sensor?
What is the maximum measuring range of the HC-SR04 sensor?
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How does the Arduino calculate the distance measured by the HC-SR04?
How does the Arduino calculate the distance measured by the HC-SR04?
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If the time of flight for an ultrasonic pulse is measured as $t$ seconds when using an HC-SR04, and the speed of sound is denoted as $v$, what is the correct formula to calculate the distance to the object?
If the time of flight for an ultrasonic pulse is measured as $t$ seconds when using an HC-SR04, and the speed of sound is denoted as $v$, what is the correct formula to calculate the distance to the object?
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An HC-SR04 sensor returns no echo signal. Which of these is the LEAST likely reason?
An HC-SR04 sensor returns no echo signal. Which of these is the LEAST likely reason?
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If the HC-SR04 sensor is operating near its maximum range, which of these factors could introduce error MOST significantly?
If the HC-SR04 sensor is operating near its maximum range, which of these factors could introduce error MOST significantly?
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The HC-SR04 sensor sends out an ultrasonic pulse at 40kHz. If an object is detected and an echo is received after 294 microseconds, what is the approximate distance to the object, assuming the speed of sound is approximately 340m/s?
The HC-SR04 sensor sends out an ultrasonic pulse at 40kHz. If an object is detected and an echo is received after 294 microseconds, what is the approximate distance to the object, assuming the speed of sound is approximately 340m/s?
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Which of the following statements best describes the nature of the ultrasonic pulse emitted by the HC-SR04 sensor?
Which of the following statements best describes the nature of the ultrasonic pulse emitted by the HC-SR04 sensor?
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Study Notes
HC-SR04 Ultrasonic Sensor with Arduino
- The HC-SR04 is an ultrasonic sensor that measures distances between 2 cm and 400 cm.
- It uses sonar principles to measure distance by sending sound waves and calculating the time taken for the echo to return.
- The sensor has a trigger pin that sends an ultrasonic pulse (8 cycles at 40 kHz), and an echo pin that receives the reflected pulse.
- The Arduino calculates the distance using the time of travel and the speed of sound (343 m/s or 0.0343 cm/µs).
Sensor Specifications
- Operating Voltage: 5V DC
- Operating Current: 15 mA
- Operating Frequency: 40 kHz
- Minimum Range: 2 cm / 1 inch
- Maximum Range: 400 cm / 13 feet
- Accuracy: 3 mm
- Measuring Angle: <15°
- Dimension: 45 x 20 x 15 mm
Distance Calculation
- To calculate the distance, the total time taken for the sound wave to travel to the object and return is measured.
- This total travel time is then divided by 2 to get the one-way distance.
- The formula is: Distance = (Travel Time × Speed of Sound) / 2
Arduino Code Example
- The code ensures proper communication through
Serial.begin(9600). -
pinMode(TRIG_PIN, OUTPUT),pinMode(ECHO_PIN, INPUT)sets the trigger and echo pins for proper functionality. - The code clears the trigger pin using
digitalWrite(TRIG_PIN, LOW). - Timing is crucial, so
delayMicroseconds(2);anddelayMicroseconds(10);control the pulse and subsequent readings. -
duration = pulseIn(ECHO_PIN, HIGH);reads the time the echo takes to return. -
distance = (duration * 0.0343) / 2;calculates the distance based on the travel time. - This example calculates the distance, providing a clear output to the serial monitor using
Serial.print().
Another Code Example (with Library)
- This example program uses a library (
NewPing.h) for simpler distance calculations. - Defines
MAX_DISTANCEto control the sensor's range. -
NewPing()within the code initializes a new sonar object with the associated pins.
Example LCD Display Code
- Uses an I2C LCD library for controlling a Liquid Crystal display (LCD).
-
LiquidCrystal_I2C Icd(0x27, 16, 2);establishes the LCD connection. - Initializes LCD components and sets the display backlight on.
- Displays "Ultrasonic Sensor" message on the first line.
- Includes
delayfor visual clarity, preventing rapid scrolling.
Additional Notes
- These delay values are crucial for the sensor's accurate pulse sending and receiving. The calculation assumes a consistent speed of sound, and the sensor is properly calibrated.
- Zero value returned by the sensor implies the reading is outside the set maximum or minimum distance.
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Description
Explore the functionality of the HC-SR04 ultrasonic sensor and how it can be integrated with Arduino. Learn about its specifications, operating principles, and distance calculation techniques. Test your knowledge with this quiz focused on sensor technology and practical applications.
