How ultrasonic sensor works ? || Working of ultrasonic sensor HC SR-04

Summary

In this 'Crazytronics' tutorial, the host explains the workings of an ultrasonic sensor, ideal for distance measurement. The sensor operates using ultrasound waves, which are beyond the human hearing range. It consists of a transmitter and a receiver, both piezoelectric transducers, and has four pins: VCC, trigger, echo, and ground. The sensor sends out ultrasonic pulses, and the echo pin signals the time until the pulse is reflected back. The distance is calculated using the speed of sound and the time duration, which is measured in microseconds. The HC-SR04 model's range is 2cm to 4m, and its accuracy is affected by temperature variations. The video promises a follow-up on interfacing the sensor with Arduino.

Takeaways

• 🔊 Ultrasonic sensors are used for distance measurement and operate using ultrasound frequencies higher than what humans can hear (20 kHz to 20 kHz).
• 📡 The sensor consists of two piezoelectric transducers: one transmitter and one receiver, which are responsible for sending and receiving ultrasonic pulses.
• 🔌 It has four pins: VCC for 5V power supply, a trigger pin for sending a 10-microsecond high pulse, an echo pin for output, and a ground pin.
• 💡 The working principle involves sending an 8-cycle ultrasonic pulse, which then gets reflected off an object and received back by the sensor, with the time duration measured by the echo pin.
• ⏱️ The pulseIn function measures the time duration for which the echo pin is high, which is used to calculate the distance.
• 📐 The formula to calculate distance is speed of sound (343 meters/second) multiplied by the time duration divided by 2, converted to centimeters and microseconds.
• 🚫 The HC-SR04 model of ultrasonic sensor has a range of 2cm to 4m, which is important for practical applications.
• 🌡️ The speed of sound, and thus the sensor's accuracy, can be affected by temperature changes, so it's not suitable for environments with fluctuating temperatures.
• 🔍 The sensor's accuracy is based on the time it takes for the ultrasonic pulse to travel to an object and back, which is why it's divided by 2 in the formula.
• 📚 The tutorial will continue with interfacing the ultrasonic sensor with an Arduino in the next video, indicating a series of educational content.

Q & A

What is the primary use of an ultrasonic sensor?

An ultrasonic sensor is primarily used for distance measurement.

Why can't humans hear the sound produced by an ultrasonic sensor?

Humans can't hear the sound produced by an ultrasonic sensor because it operates at a frequency higher than the audible range for humans, which is 20Hz to 20kHz.

What are the two main components of an ultrasonic sensor?

An ultrasonic sensor consists of two piezoelectric transducers: one is a transmitter that sends ultrasonic pulses, and the other is a receiver that captures the returning ultrasonic pulses.

What are the four pins found on an ultrasonic sensor?

The four pins on an ultrasonic sensor are VCC for power supply, trigger pin for receiving a high pulse, echo pin for output, and ground pin.

How does the trigger pin function in an ultrasonic sensor?

The trigger pin receives a 10-microsecond high pulse, which prompts the transmitter to emit 8 ultrasonic pulses.

What happens when the echo pin of the ultrasonic sensor gives a high output?

The echo pin gives a high output when the ultrasonic pulses are emitted by the transmitter and before they are reflected back and received by the receiver.

How is the time duration of the echo pin's high output measured?

The time duration of the echo pin's high output is measured using the pulseIn function.

What is the formula used to calculate the distance using an ultrasonic sensor?

The formula to calculate the distance is speed of sound times time divided by 2.

Why is the speed of sound divided by 2 in the distance calculation formula?

The speed of sound is divided by 2 because it accounts for the time it takes for the pulse to travel to the object and back to the sensor.

What is the typical operating range of the HC-SR04 ultrasonic sensor?

The HC-SR04 ultrasonic sensor has a range of 2cm to 4m.

How does temperature affect the performance of an ultrasonic sensor?

The speed of sound, and thus the performance of an ultrasonic sensor, changes with temperature. Therefore, it's not recommended to use the sensor in environments with fluctuating temperatures.