with the ESP32

If you want to build a robot that can avoid obstacles but are just starting out as an electronics engineer, the first thing you need to do is educate yourself on how an obstacle avoidance system operates. Because of this, the project that we are working on is of the utmost significance. In this project, we are going to interface an HC-SR04 Ultrasonic Distance Sensor module with ESP32, and as a result, we are going to become intimately familiar with every aspect of the module. Since the module is an essential component of any obstacle avoidance or detection system, this makes this project particularly significant. As a result, during the course of this project, we will become familiar with each and every facet of the HC-SR04 Ultrasonic Distance Sensor module as well as the process of interfacing it with ESP32. The ultrasonic HC-SR04 sensor has a detection range of 13 feet and an angle of 15 degrees, making it an excellent tool for locating obstructions. Aside from that, it has a very low operating current, making it exceptionally well-suited for use in applications that are powered by batteries. In our earlier efforts, we were

able to construct a wide variety of fascinating projects by combining an Arduino and a PIC microcontroller with this HC-SR04 board. The Pinout of the HC-SR04 Ultrasonic Sensor VCC, Trig, Echo, and Gnd are the names of the module's four available pins on the HC-SR04 ultrasonic proximity sensor. Because both the input and output of this sensor are digital, we need to connect it to the microcontroller's digital pin in order to use it. The HC-pinout SR04's is shown in the following image. VCC - The supply pin of the HC-SR04 Module. Establish a connection between it and the ESP32's 5V pin. Trig - This is the trigger pin of the HC-SR04 module. An ultrasonic burst can be triggered from the sensor by setting this pin to HIGH for ten microseconds. Echo - This is the HC-SR04 sensor module's echo pin. This pin holds its high state until either the sensor receives the echo back or a predetermined amount of time has elapsed.

GND - This is the module's Ground pin; join it to the ESP32's Ground pin. HC-SR04 Ultrasonic Sensor Overview Before we move on to figuring out how the ultrasonic distance sensor operates, let's first get a better understanding of what ultrasound is: Ultrasound is a type of high-pitched sound wave in which the frequency of the wave is higher than what is audible to humans due to the human ear's limited range. The audible range for humans is between 20 Hz and 20 kHz; however, the sound that is emitted from the module is significantly higher in frequency than what human ears are able to process, and as a result, it is inaudible to humans. Two ultrasonic transducers are used in the construction of an ultrasonic distance sensor. One of these transducers has a frequency of 40 kilohertz and functions as a transmitter, while the other functions as a receiver and listens to the reflected received pulses. The output pulse that the sensor generates is in a manner that is proportional to the distance between it and the object that is being sensed. The sensor has an operating voltage of 5 volts and can provide excellent non-contact range detection between 2 cm and 400 cm. The distance of the object can be determined by reading the pulse width with a microcontroller, and this can be done to determine how far away the object is. The ultrasonic sensor can be interfaced with any microcontroller; if you follow the link, you will find information on all of the possible interfaces for the ultrasonic sensor. What is the operation of the HC-SR04 Ultrasonic Distance Sensor? In order to get the process of measuring distance started, we need to set the trigger pin to high for ten microseconds. As a response, the sensor sends out an ultrasonic burst consisting of eight pulses at a frequency of forty

kilohertz. The eighth pulse is constructed in such a way that it enables the receiver to differentiate between the transmitted pulse and the background ultrasound. When the process of sending 8 pulses is complete, the echo pin will go high, which will indicate that the return signal has been received. In the event that those transmitted signals do not return after 38 milliseconds, this indicates that there is no obstruction in the path of the sensor. If those pulses are reflected back, the echo pin will go low as soon as the signal is received. This will cause a pulse to be generated on the echo pin, the width of which will range anywhere from 150 microseconds to 25 milliseconds, depending on how long it took to receive the signal.

Calculating the Distance by measuring the pulse width We can use the equation for distance, speed, and time in conjunction with the received pulse width to calculate the distance from the reflected object. This can be done by using the received pulse width. Let's assume that we have no idea how far X is from us, but that we have measured a pulse width of 700 microseconds on the echo pin. Following is the formula that will be used by us now when figuring out the distance. Distance = Speed x Time We now know that the speed of sound is 343.2 meters per second. We need to convert the speed of sound to cm/uS, which comes out to 0.03432 cm/uS, so that we can calculate the distance. In addition to this, we need to know the time value that was received from the ultrasonic sensor, which is 700 uS. Distance = (0.03432 cm/us x 700uS) / 2 = 12.012 cm

The distance between the object and the sensor is now known to be 12.012 centimeters. Ultrasonic range sensor module HC-SR04: Frequently Asked Questions Q. What is the upper limit of the HC-range? SR04's The HC-SR04 has a maximum range of 400 centimeters, which is equivalent to 13 feet. Q. Can HC SR04 detect water? Yes, this sensor is able to determine the height of the water's surface, and this information can serve as an early warning of an impending flood. There are a lot of projects that involve water surface-level detection systems that are available on the internet. These systems make use of ultrasonic sensors and the ESP8266-12E module. Q. Is the ultrasonic sensor HC-SR04 waterproof? The HC-SR04 module is extremely delicate; it is susceptible to damage from dust and can even be blown apart by strong winds; moreover, it is not waterproof. However, there are specific modules that can withstand high levels of humidity and can be purchased on the market today. These modules were developed with some level of water resistance built into their designs. Q. Does HC SR04 work with 3.3 V? The datasheet indicates that it cannot be powered by 3.3V, but there is a workaround: you can use 3.3V to trigger the module, and then in the echo line, you can use a voltage divider to reduce the voltage to 3.3V using an appropriate one. ESP32 with HC-SR04 Ultrasonic Sensor Circuit Diagram

Now that we have a comprehensive understanding of how the HC-SR04 ultrasonic module operates, we have connected all of the required wires to the ESP32 module. Next, we will write a straightforward code in order to test the module and ensure that it is functioning properly. The illustration below shows the full test schematic for connecting the ESP32 to the HC-SR04 sensor. The HC-SR04 module and an OLED module have been connected to the ESP32, as can be seen in the image that is located above this one. Because the ultrasonic module requires 5V to function, the procedure for connecting it is very straightforward. Because of this, we have implemented a voltage divider in the echo pin in order to reduce the 5V output to 3.3V. For the HC- SR04 module, any digital pin of the ESP32 can be used as an I/O; however, for the OLED model, you need to use the I2C pin, which is the IO21 and IO22 of the ESP32 module. You can use any digital pin of the ESP32 for the HC-SR04 module. The procedure for making the connection is now complete; the image of the hardware that can be found below will provide you with a clearer picture of how the circuit is connected.

How to Use Arduino Code to Connect HC-SR04 Sensor to ESP32 In the following section of this article, we will be describing the code that will be utilized to measure the distance with the HC SR04 sensor and display the results on the 128X64 display. However, before we begin the process of writing code, we will need to install the Adafruit GFX library, the Adafruit SSD1306.h library, and the NewPing.h library from the library manager of Arduino in order to process the data coming from the sensor and display. When we first begin work on our code, we begin by including all of the necessary libraries. These libraries include the Adafruit GFX library as well as the NewPing library. Since the SPI library and the Wre library are dependencies of the Adafruit GFX library, we need to include those two libraries first before we can include the Adafruit GFX library. How to Fix Issues with the HC-SR04 Ultrasonic Sensor Module If you are having issues connecting the HC-SR04 to the ESP32, the first thing you need to do is check the power line. If you try to power the ultrasonic sensor module with 3.3V instead of 5V, the module will be unstable. The module was designed to work with a supply of 5V. If you are working with a library that is not supported by your module, the module may provide you with inaccurate information. Therefore, you need to check the library that you have installed or you need to install the appropriate library for the module. If the module is still not functioning properly, you might want to examine it alongside another module.