Learn Everything About Ultrasonic Sensor HC SR04

Raj Sawkare
13 min readSep 18, 2023

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What is Ultrasonic Sensor

HC-SR04 stands for High-Conductance Ultrasonic Sensor consists of a transmitter and receiver. The sensor measures how far things are without touching them, and it uses sound waves to get the measurements right. It can work well when things are between two to four centimeters away. Just like other tools that measure distances, this sensor doesn’t harm objects. So, it’s good for things that are around two to four centimeters away.

The HC-SR04 creates sounds we can’t hear, which help us figure out how far things are or how they’re placed. The sensor can feel things within a specific area. To get it to function, you need to lift the Trig pin while keeping the Echo pin down for roughly 10 seconds.

The Ultrasonic sensor can tell you how far things are, even if they’re as distant as 13 feet. It’s really cheap and easy to use, which is great for robots that run on batteries. This thing kind of looks like the eyes of Wall-E the Robot. It sends out sounds you can’t hear, and these sounds are like 40,000 little vibrations per second. The farther away things are, the quieter the sounds get. Depending on how far stuff is, you can use this sensor for all sorts of things. You can also study how the sensor works to get what it does.

Every time the wave reflects, the HC-SR04 produces a pulse. The time between the transmitted wave and the reflected signal is proportional to the distance, and the longer the time, the greater the distance. The sensor can determine the distance between the transmitter and the object when this pulse is high. It is an excellent tool for robot obstacle avoidance and path-finding applications. This is the ultrasonic sensor definition.

How Ultrasonic Sensor Works

How Ultrasonic Sensor Works: This technology detects objects by measuring the sound they produce. These sensors can detect levels and distances. But some factors affect their performance. When designing ultrasonic sensors, it’s essential to consider factors such as the speed of sound through air, as well as elements like humidity, temperature, and air pressure.

To make this sensor work well, the thing you’re trying to sense needs to bounce back the sound waves. The sensor should be facing straight at the thing, and it’s best if the angle is really small, like less than 3 degrees. If the thing is bumpy, the angle can change and mess up the results. So, pick something smooth. To make the ultrasonic sensor do its best, think about power, how it’s connected, the instructions you give it, and how far you want it to work.

A typical ultrasonic sensor emits a high-frequency sound pulse that propagates through air. Once the sound reaches the object, it bounces off and returns to the sensor. The sound pulse’s travel time between the transmitter and the receiver determines the distance, utilizing the principle of measurement known as transit time measurement. Additionally, this principle plays a crucial role in accurately assessing distances in various applications. This method is a powerful one for many purposes. Compared to other modules, the working of the ultrasonic sensor is notably superior.

The Ultrasonic Sensor Module is a circuit with four pins. The trigger pin acts as the input pin and must be held high for about 10 us to detect the transmitted signal. On the other hand, the echo pin functions as the output pin. When the reflected signal arrives, it causes an output pulse, converted into an electrical signal. This signal is then passed on to a signal processing system.

Information on Ultrasonic Pulse Velocity Test

An ultrasonic pulse velocity (UPV) test is a safe way to examine concrete and rocks. This test helps us understand how strong they are. It works by sending quick sound waves through them and seeing how fast they travel. This helps us figure out their properties and quality.

In this test, we pass a pulse of ultrasonic waves through the cement we want to check. We measure how long it takes for the pulse to move through the material. Higher speeds demonstrate great quality and progression of the material, while more slow speeds might show concrete with many breaks or voids.

The Ultrasonic testing equipment has a circuit that makes quick pulses. This circuit creates pulses and sends them to a part that changes them into vibrations you can’t hear. These vibrations are pretty fast, around 40 kHz to 50 kHz. Another part of the equipment catches these signals.

How Ultrasonic Sensor Works With An Arduino

Learn how Ultrasonic Sensors collaborate with Arduinos to gauge distance using sound waves. The sensor emits sound, tracks its return time, and calculates the time taken for the wave’s round trip. The gap between emission and reception time determines the object’s distance from the sensor. To use an ultrasonic sensor with Arduino you should know about Arduino Uno R3 properly.

The HC SR04 Ultrasonic Sensor uses four pins to transmit and receive sound waves. These pins are connected to an Arduino UNO or the original board. The Trig pin sends the sound waves while the Echo pin receives the waves. You can use the serial monitor to see the sensor readings. The sensor will send a signal back to the Arduino if the distance is correct.

The Ultrasonic Sensor with Arduino reports the distance to an object up to 13 feet away. The sensor is powered by the battery and is easy to interface with. The sensor’s appearance resembles the eyes of a Wall-E robot. The speed of sound in water is 4.3 times faster than in air. Depending on the distance, you can position the sensor near the bottom of a body of water.

The HC SR04 ultrasonic sensor measures distance and is used with an Arduino as a small device. The sensor’s working principle is similar to that of SONAR, which ships use to navigate underwater. It measures distance by emitting and receiving sound waves. It sends out sound waves and then catches the ones that bounce back. The transmitter pin initiates the transmission of sound waves, and the receiver pin goes to the circuit ground.

What Can an Ultrasonic Sensor Detect?

What can an Ultrasonic Sensor Detect? These devices are used to detect the level of bulk goods. Their high-quality sonic reflection allows them to detect objects of the same color or shape. Another benefit is their ability to measure a wide area without touching the object they are sensing. The technology behind ultrasonic sensors uses piezoelectric ceramics to transmit sound waves.

Unlike lasers, the ultrasonic signals produced by an ultrasonic transmitter are acoustic waves, similar to a flashlight light. Because the distance between the transmitter and the target increases, the detection area grows. Ultrasonic sensors give details about how wide their detection area is by using terms like “beam angle” and “beam width.” You need to check the beam angle to make sure it covers the whole space you want to sense. The beam angle is how much the detection area’s direction is different from where the sensor is placed.

Using an ultrasonic sensor for detection requires some advanced knowledge of physics. It is essential to understand that the ultrasonic sensor range of detection varies depending on the temperature and air pressure of the target. In dry air, the sound propagates at a velocity of 343 m/s. This velocity is enough to cover a kilometer in 2.91 seconds. Objects that have a high refractive index will reflect the sound toward the sensor. Permeable targets absorb the ultrasonic energy and thus reduce its range of detection.

Is Ultrasonic Sensor Waterproof?

If you’re buying an ultrasonic sensing system, it’s important to know if your ultrasonic sensor is waterproof. Thankfully, most ultrasonic sensors are. This article will explain how they work and what you should look for when purchasing one. Also, the waterproof ultrasonic sensor is a bit costly compared to a normal one. Read on to discover whether your sensor is waterproof and what to look for in a waterproof Ultrasonic Sensor. After all, the more information you have about a product, the better equipped you’ll be to make a good purchase.

A waterproof ultrasonic sensor uses a single ultrasonic transducer, both the transmitter and the receiver. These sensors are best used when they’re not going to be inaccessible or prone to a high-risk environment. This makes ultrasonic sensors great for outdoor projects and industrial settings. You can find waterproof sensors that have a wide operating angle. The JSN-SR04T model is one example.

The water resistance of your ultrasonic sensor depends on how you plan to use it. It can sense things by feeling their surface. If you want to use it in industries, it’s a good idea to get a waterproof one. You can do this by either buying a sensor with waterproofing already included or by making sure the product you choose is labeled as waterproof.

The waterproof Ultrasonic Sensor offers a solution to this problem. The only downside to this product is its limited distance and range. If this is correct it’s not a true waterproof ultrasonic sensor. This device is only useful for measuring distances up to a certain range. You should also make sure your sensor can work with liquids and slurries.

How to Mount Ultrasonic Sensor on Servo Motor

To mount an ultrasonic sensor on a servo motor, you need to know how to mount it. All you need is four wires, but you can use one if you have only two. You can use a cable tie to hold the servo motor and sensor wires to a servo stand. You need to connect the Ultrasonic Sensor with Servo Motor using the ribbon cable. Once you have completed this step, you can mount the ultrasonic sensor with a servo motor.

Once you have everything you need, you can attach the sensor to a servo motor. To do this, you’ll need a special bracket for the sensor. You can find one to buy on the Internet. But if you want, you can make one yourself. You just need a servo motor and a certain kind of cable. The sensors have one type of connector, so make sure to choose the right kind of bracket that works with the servo motor.

The Ultrasonic sensor mounting bracket comes with velcro dots that will allow it to secure the servo. Since the bracket permits angle adjustments, it shouldn’t pose significant complexity for a beginner. Nevertheless, if you possess knowledge of mounting servos and ultrasonic sensors, you can leverage this guide to initiate your project. You can also add a sounder to the Arduino to make the alarm more audible.

Ultrasonic Sensor Application

The PING ultrasonic sensor works with 3 pins: GND, Vcc, and Signal. The speed of sound is approximately 340 m/s or 29 microseconds per centimeter. Ultrasonic sensors are commonly used for level and distance measurements. As they can detect anything that is in the way, including people.

There are two main kinds of ultrasonic sensors: one that can sense things only within a certain range, and another that can sense things through surfaces. The limited range sensor needs a part that sends out sound and another part that listens for the sound to come back. When the sound bounces back from something, it tells the sensor there’s something there. The edge of the limited-range sensor also has something that helps the sound bounce back.

For performing an ultrasonic measurement, the transducers must receive an ultrasound signal. The ultrasonic signal is then converted into electrical energy by an oscillator with a diameter of 15 mm. The part called the “transducer” sends out the special sound waves, and the “receiver” part has a circuit that figures out how strong the sound that comes back is. This circuit needs electricity to work, so it gets power from a special kind of battery that keeps the voltage steady.

The multiple-vibrator kind has a special piece made of a certain kind of ceramic that makes a sound when you put electricity through it. This piece is shaped like a cone, which helps the sound spread out and focus in the middle of the piece. The special piece is most sensitive to sound at a certain frequency, and that’s when it works the best. Moreover, the directivity of the beam pattern makes it possible to detect an object’s position in space.

Ultrasonic Sensor HC SR04 Module

The Ultrasonic Sensor HC SR04 offers many more features, such as low-power data transmission, high-speed data transfer, etc. It is a full-duplex communication which means both sender and receiver transmit and receive data at a time.

Besides, the Ultrasonic Sensor HC SR04 FHSS uses frequency-hopping spread spectrum radio technology. This technique provides many advantages of communication over a noisy channel and prevents the signal from being hacked or jammed.

We were talking about the Ultrasonic Sensor HC SR04’s features and showed how it is an alternative option for short-distance communication. Later, we will talk about its pinout diagram and its interfacing with Arduino Uno, 8051.

Pinout of HC-04

HC-04 Pinout

The Ultrasonic Sensor HC SR04 Bluetooth module uses UART communication to transfer data to the master and uses two pins, Rx and Tx, to do this job. The pinout details of the Ultrasonic Sensor HC SR04 device are as follows:

VCC and GND

These pins are used for powering the module.

Ultrasonic Sensor HC SR04 has two modes of operation those are as follows:

1. Data Mode

By default, the Ultrasonic Sensor HC SR04 mode works in data mode. In this mode, HC-04 sends and receives data from other devices.

2. Command Mode

In this mode, Ultrasonic Sensor HC SR04 accepts AT commands from the user and reacts to the commands accordingly.

Arduino Code For Ultrasonic Sensor

You’ve come to the right place if you’re looking for an Arduino Code for Ultrasonic Sensor. This library aims to make access to ultrasonic distance measurements easy for everyone. However, with a large amount of online information, navigating through the code can be challenging. The first step in creating a useful ultrasonic sensor is to select a sensor. The HC-SR04 is a popular option. You can also code ultrasonic sensors with Arduino.

To use an ultrasonic sensor with Arduino, you must first connect it to an Arduino microcontroller. You can use an Arduino UNO R3 or an Arduino Pro Mini. This ultrasonic sensor has four pins: the Trig pin, the Echo pin, and the output pin. The outputs from this sensor are converted to distance using the time delay. Using this information, you can calculate the distance to an object. Since the speed of sound is 343 meters per second, the distance measurements you get are accurate.

To connect the sensor to your computer, you’ll need an A to B cable and a USB port. And then, you need to choose the Arduino UNO as your board and the Arduino UNO as the COM port. You can find these settings under Tools > Board and Port in Arduino. The serial monitor window will appear. You can enter the code to get your sensor readings. Here you can copy Arduino Code for Ultrasonic Sensor from the document. Download the document of code below.

Arduino Code for Ultrasonic Sensor

While using the Arduino Code for Ultrasonic Sensor check the syntax and code properly for zero error. You can also check the source for the proper Arduino Code for Ultrasonic Sensor.

Ultrasonic Sensor And Servo Motor Arduino Code

An Ultrasonic Sensor And Servo Motor are simple yet effective ways to control an object. These sensors use sound waves to detect movement and send an elapsed time signal to the Arduino board. A servo motor is a type of electric motor designed for precise motion control and includes a suitable motor coupled to a sensor for position feedback. You can purchase these sensors in electronic shops or online. You can also control the servo with an ultrasonic sensor Arduino.

To control the speed of a servo motor, you must change the step size and rotation speed. These two variables will affect the number of ultrasonic sensor reads per servo position update. Increasing the step size will decrease the number of sensor updates per servo sweep. Also, you can adjust the microsecond value, which will affect the number of ultrasonic sensor reads per servo sweep.

To mount an ultrasonic sensor to Arduino, you must use a bracket. You will need a SG90 servo and a bracket for it to do this. The bracket comes with “D”-shaped washers, which will hold the sensor in place. If the sensor is tilted or looking to the left, you may need to adjust the position of the servo horn screw. You should never connect the sensor mounting screws to the center of the servo sweep. Also, you can adjust the sensor position later when the Arduino program is running. You can download a doc file for Ultrasonic Sensor And Servo Motor Arduino Code from given below button.

Ultrasonic Sensor And Servo Motor Arduino Code

Ultrasonic Sensor Datasheet

If you have searched for an ultrasonic sensor datasheet and have not gotten it. Here is the thing you can download the ultrasonic sensor datasheet from the given button below.

Ultrasonic Sensor Datasheet

How much does Ultrasonic Sensor Cost?

The ultrasonic sensor price differs from website to website. In vayuyaan, the ultrasonic sensor cost is too low compared to other sites.

Where to Buy Ultrasonic Sensor HC SR04

There are different websites on which you can buy ultrasonic sensors. In vayuyaan, we offer cheap prices for our customers. You can check the ultrasonic sensor price and can buy ultrasonic sensor by the given option below.

Buy Ultrasonic Sensor

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source: https://vayuyaan.com/blog/learn-everything-about-ultrasonic-sensor-hc-sr04/

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Raj Sawkare

Vayuyaan is the first choice for electronics & robotics components like Arduino development boards, Sensors, Drone accessories, Thermal Printer etc..!!