The Engineering Projects

Introduction to HC-SR04 (Ultrasonic Sensor)

Hi Friends! I hope you are doing well. Welcome you onboard. Today, I'll discuss the basic Introduction to HC-SR04 Ultrasonic Sensor. It is an ultrasonic sensor, also known as an ultrasonic transducer that is based on a transmitter and receiver and mainly used to determine the distance from the target object. The amount of time it takes to send and receive waves will determine how far the object is placed from the sensor. It mainly depends on the sound waves working on “non-contact” technology. The required distance of the target object is measured without any damage, giving you accurate and precise details. This sensor comes with a range between 2cm to 400cm and is used in a wide range of applications including speed and direction measurement, wireless charging, humidifiers, medical ultrasonography, sonar, burglar alarms, and non-destructive testing. In this post, I'll try to cover basic details related to HC-SR04, so you get an idea what is this about and how it can be used in the major applications as per your needs and requirements. Let's jump right in and get down to the details on this ultrasonic sensor.

Introduction to HC-SR04 ( Ultrasonic Sensor )

• HC-SR04 is an ultrasonic sensor mainly used to determine the distance of the target object.
• It measures accurate distance using a non-contact technology - A technology that involves no physical contact between sensor and object.
• Transmitter and receiver are two main parts of the sensor where former converts an electrical signal to ultrasonic waves while later converts that ultrasonic signals back to electrical signals.
• You can download HCSR04 Datasheet by clicking below button:

Download HC-SR04 Datasheet

• These ultrasonic waves are nothing but sound signals that can be measured and displayed at the receiving end.
• Following table shows the main features of this ultrasonic sensor.

 

Parameter	Value
Main Parts	Transmitter & Receiver
Technology Used	Non-Contact Technology
Operating Voltage	5 V
Operating Frequency	4 MHz
Detection Range	2cm to 400cm
Measuring Angle	30º
Resolution	3mm
Operating Current	<15mA
Sensor Dimensions	45mm x 20mm x 15mm

 

• It gives precise measurement details and comes with accuracy (resolution) around 3mm, terming there might be a slight difference in the calculated distance from the object and the actual distance.

HC-SR04 Pinout & Description

• HC-SR04 contain 4 pins in total.
• Following table shows the HC-SR04 Pinout  & Description:

 

No.	Pin Name	Pin Description
1	VCC	The power supply pin of the sensor that mainly operates at 5V DC.
2	Trig Pin	It plays a vital role to initialize measurement for sending ultrasonic waves. It should be kept high for 10us for triggering the measurement.
3	Echo Pin	This pin remains high for short period based on the time taken by the ultrasonic waves to bounce back to the receiving end.
4	Ground	This pin is connected to ground.

 

• I have labelled these HC-SR04 Pinout in below figure for better visualization:

How does it work?

The HC-SR04 Ultrasonic (US) sensor is an ultrasonic transducer that comes with 4 pin interface named as Vcc, Trigger, Echo, and Ground. It is very useful for accurate distance measurement of the target object and mainly works on the sound waves. As we connect the module to 5V and initialize the input pin, it starts transmitting the sound waves which then travel through the air and hit the required object. These waves hit and bounce back from the object and then collected by the receiver of the module. Distance is directly proportional to the time these waves require to come back at the receiving end. The more the time taken, more the distance will be. The waves will be generating if the Trig pin is kept High for 10 µs. These waves will travel at the speed of sound, creating 8 cycle sonic burst that will be collected in the Echo pin. The echo pin remains turned on for the time these waves take to travel and bounce back to the receiving end. This sensor is mainly incorporated with Arduino to measure the required distance. Following formula is used to calculate the distance of the object.

S = (V x t)/2

Where S is the required distance, V is the speed of sound and t is the time sound waves take to come back after hitting the object. We need to divide the value by 2 because time will be double as the waves travel and bounce back from the initial point. Dividing it by 2 will give the actual distance of the target object.

Using HC-SR04 with Arduino Module

In order to get the precise distance measurement, HC-SR04 is mostly used in combination with different Arduino Modules like Arduino Uno and Arduino Mega. You can connect Arduino with this sensor in the following way.

• First, you need to power up the sensor using 5V DC regulated input to the sensor. Connect the ground pin with the ground of the voltage source. You can also power the sensor module using the Arduino 5V pins as the current drawn by the sensor is less than 15mA, won't be affecting the current ratings of the Arduino Module.

After setting up the initial arrangement, connect both Trig and Echo pins to the I/O pins of the Arduino Board. As mentioned earlier, in order to initialize the measurement process, the Trig pin must be kept high for 10us in the start. The sensor module will start generating sound waves with the frequency around 40,000 Hz per second from the transmitter.

• As the waves bounce back, consequently, the Echo pin will turn on until the sounds waves are received by the receiver. This time will be calculated using Arduino Module.

This tutorial that will help you How to Interface Ultrasonic Sensor with Arduino Module You can also Interface Multiple Ultrasonic Sensors with Arduino Module

Applications

HC-SR04 comes with a wide range of applications mainly targeting distance and direction measurements. Following are the major applications it can be used for.

• Speed and direction measurement
• Wireless charging
• Humidifiers
• Medical ultrasonography
• Burglar alarms
• Embedded system
• Depth measurement
• Non-destructive testing

That's all for today. I hope I have given you everything you needed to know about this sensor. If you are unsure or have any question, you can approach me in the comment section below. I'd love to help you the best way I can. Feel free to keep us updated with your valuable feedback and suggestion, they help us stay above the curve and give you quality content as per your demands. Thanks for reading the article.

Introduction to Laser Sensor

Hello everyone! I hope you all will be absolutely fine and having fun. Today, I am going to provide a detailed discussion on Introduction to Laser Sensor. Laser  sensor is basically an electronic device which we often use for the detection of accurate positions as well as small objects. Laser sensors transmit or radiate laser light. This laser light consists of light waves having same wave length. Due to this fact laser light travels in a parallel direction from the source emitting this light. Due to its travel in parallel direction it can be transmitted over long distances. This light is dangerous for the human beings. We must avoid by looking directly into the light. It causes serious eye damaging effect and even can make anyone blind. As we know optical fiber cables are used for the communication theses days and it uses only light to transmit data. If the communication is for shorter distance, LED will be used as a information transmitting source. If we want to communicate over long distances we must use laser because it has the light waves of same wave lengths and has a capability to be transmitted over long distances. If we use laser for the shorter distance communication, the medium will be overloaded with a lot of information and hence data will be damaged and can not be sent to the receiving end. Laser sensor has basically two wires but if it is attached on a small PCB board, then it has three pins which will be discussed later. The further information about laser sensor module will be provided later in this tutorial.

Introduction to Laser Sensor

Laser Sensor is an electronic device usually used to detect small objects. It is also used to detect the accurate positions. Laser light has light waves of same wave lengths. Due to the fact, laser light travels in a parallel direction. It is dangerous for humans because it can cause serious eye problems, if you look directly into the light when it is ON. It can cause blindness too. It can be used to transmit data over long distances, which is considered to be its major benefit. Laser sensor module is shown in the figure given below.

1. Laser Sensor Pins

• Laser sensor has basically two pins, usually known as power pins.
• Both of the pins are provided in the table shown in the figure below.

2. Laser Sensor Pins Description

• We must know about the functions of all the input/output pins in order to use the device properly.
• Laser sensor pin descriptions is given in the table provided in the figure given below.

3. Laser Sensor Working Principle

• Laser radiated a laser beam as shown in the figure below.
• Receiver lens concentrates the light reflected off the target, and produces an image on a light receiving element.
• The concentrated light reflects at several different angles, when distance changes.
• With the change in angle of the concentrated light, position of the image changes correspondingly.
• I have provided the three visuals at different distances in the figure shown below.
• From the three figures given below, you can easily understand the working principle of a laser sensor.
• The laser principle for reference distance is shown in the figure below.

• The laser principle for shorter distance is shown in the figure given below.

• Laser principle for longer distance is shown in the figure given below.

4. Laser Sensor Ratings

• Ratings provides us the basic and general specifications of any electronic device.
• Laser sensor ratings are given in the table shown in the figure given below.

5. Laser Sensor Applications

• Most of the times the electronic devices are known on the basis of their applications.
• Laser sensor has a wide range of real life applications.
• Some of the common applications are listed in the table shown in the figure given below.

6. Laser Sensor Advantage

• Advantages are the parameters which can improve the efficiency of the particular device.
• Laser Sensor advantages are shown in the table given in the figure below.

7. Laser Sensor Disadvantage

• Like other devices laser sensor also has some serious disadvantages.
• Few of the main and avoidable disadvantages are listed in the table shown in the figure given below.

In the tutorial Introduction to Laser Sensor, I have explained about the basic parameters associated with the laser sensors and which are important to be known before using it. I hope you have enjoyed the tutorial and hoping for your appreciation. If you have any sort of problem you can ask us in comments any time. Our team is always there to help to help you. I will share different amazing and informative topics in my upcoming tutorial. Till then take care and bye :)