Introduction:

Welcome, tech enthusiasts, to another thrilling journey into the realm of ESP32 microcontrollers! In today’s tutorial, we’re diving deep into the world of touch sensors and seven-segment displays, all expertly explained using ESP-IDF. Whether you’re 18 or 30, this comprehensive guide is tailored to fuel your passion for embedded systems and take you one step closer to becoming a pro in Python and IoT. So, grab your ESP32 board, and let’s embark on this enlightening adventure!

Understanding ESP32 and ESP-IDF:

Before we embark on our journey, let’s meet our key players:

• ESP32: The ESP32, born from the brilliant minds at Espressif Systems, is a versatile microcontroller celebrated for its prowess in the world of IoT. Its capabilities are boundless, making it the perfect companion for your next project.
• ESP-IDF: The ESP32 IoT Development Framework (ESP-IDF) serves as the official development platform for the ESP32. It’s equipped with a toolbox of tools and libraries to simplify the creation of applications that run seamlessly on this powerful microcontroller.

Understanding Touch Sensors:

Touch sensors, often referred to as touch-sensitive switches or touch pads, are electronic components that detect physical touch or proximity. These sensors can be found in a wide range of devices, from your smartphone’s screen to interactive kiosks and even household appliances like microwave ovens.

How do touch sensors work? They rely on various technologies, including capacitive sensing, resistive touch, and surface acoustic wave (SAW) technology. When you touch a surface equipped with a touch sensor, it detects the change in capacitance or resistance caused by your touch, translating it into an electrical signal. This signal is then processed to trigger specific actions or responses in the connected device.

Understanding Seven-Segment Displays:

Seven-segment displays are common output devices used for displaying numbers, letters, and basic symbols. They consist of seven individual segments, typically arranged in the shape of the number “8.” Each segment can be independently controlled to form numbers from 0 to 9 and some letters, making them suitable for numerical displays, digital clocks, and basic alphanumeric readouts.

The seven segments are named “a,” “b,” “c,” “d,” “e,” “f,” and “g,” and they can be illuminated or turned off selectively to represent different characters. By controlling which segments are lit up, you can create the appearance of numbers and letters on the display.

Importance of Touch Sensors and Seven-Segment Displays:

Now that we have a basic understanding of touch sensors and seven-segment displays, let’s explore why they are essential components to learn and work with:

1. Real-World Applications: Both touch sensors and seven-segment displays are ubiquitous in our daily lives. Understanding how to integrate them into your projects opens up opportunities to build devices with practical applications, such as interactive interfaces, digital counters, and temperature displays.
2. Hands-On Experience: Working with touch sensors and displays provides hands-on experience in interfacing with electronic components and microcontrollers like the ESP32. These skills are valuable for anyone looking to pursue a career in electronics, IoT, or embedded systems.
3. Foundation for Complexity: Learning the basics of these components lays a strong foundation for tackling more complex projects in the future. Once you grasp the fundamentals, you can explore advanced topics like capacitive touch interfaces and multiplexed displays.
4. Creativity Unleashed: Armed with the knowledge of touch sensors and seven-segment displays, you can unleash your creativity and invent innovative solutions. Whether it’s designing a touch-sensitive game or building a custom digital clock, the possibilities are endless.

With this comprehensive understanding of touch sensors and seven-segment displays, you’re well-prepared to dive into our tutorial on integrating them with the ESP32 using ESP-IDF. So, let’s roll up our sleeves and embark on this exciting journey!

Why Touch Sensor and Seven-Segment Display?

You might be wondering why we’re focusing on touch sensors and seven-segment displays. Here’s why:

1. Touch Sensors: Touch sensors are a ubiquitous part of our lives, found in smartphones, tablets, and even kitchen appliances. Mastering touch sensor integration unlocks the door to countless real-world applications.
2. Seven-Segment Displays: Seven-segment displays are the go-to choice for displaying numbers and basic characters. Learning to control them is essential for building digital counters, timers, and clocks.
3. Hands-On Experience: These components provide hands-on experience with GPIO (General Purpose Input/Output) pins and interfacing, vital skills for any aspiring embedded systems developer.
4. Versatility: Once you’ve grasped the fundamentals, you can apply these skills to a wide range of projects, from digital thermometers to scoreboards and beyond.

Setting Up Your Environment for Touch Sensor and Seven-Segment Display:

Before we dive into the coding magic, let’s make sure your toolkit is ready:

1. Install ESP-IDF: Head to the official Espressif documentation for a step-by-step guide on setting up ESP-IDF on your machine. Don’t worry; they’ve got you covered!
2. Select Your Coding Environment: Choose a code editor or integrated development environment (IDE) that suits your style. Visual Studio Code with PlatformIO is a popular choice among developers.
3. Hardware Check: Connect your ESP32 board to your computer using a trusty USB cable. Ensure your ESP32 has a stable power source to avoid any interruptions.

Creating a New Project for Touch Sensor and Seven-Segment Display:

To begin your touch sensor and seven-segment display project, follow these steps:

# Create a new directory for your project
mkdir esp32_touch_display
cd esp32_touch_display

# Initialize the project
idf.py create-project -p . <project-name>

Here, replace <project-name> with the project name that you wish to give to your “Touch Sensor and Seven-Segment Display with ESP-IDF” project

Understanding the Code Logic of Touch Sensor and Seven-Segment Display:

With the GPIO pin configured, it’s time to write the code. Create a new file, main.c, in your project directory and add the following code:

#include <stdio.h>
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

const int seven_seg_pins[7] = {GPIO_NUM_22, GPIO_NUM_21, GPIO_NUM_19, GPIO_NUM_18, GPIO_NUM_5, GPIO_NUM_4, GPIO_NUM_2};
const int numbers[10][7] = {{0, 0, 0, 0, 0, 0, 1}, {1, 0, 0, 1, 1, 1, 1}, {0, 0, 1, 0, 0, 1, 0}, 
{0, 0, 0, 0, 1, 1, 0}, {1, 0, 0, 1, 1, 0, 0}, {0, 1, 0, 0, 1, 0, 0}, {0, 1, 0, 0, 0, 0, 0}, 
{0, 0, 0, 1, 1, 1, 1}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 1, 1, 0, 0}};

int count = 0;

void app_main(void)
{
    for (int x = 0; x < 7; x++)
    {
        gpio_set_direction(seven_seg_pins[x], GPIO_MODE_OUTPUT);
    }

    gpio_set_direction(GPIO_NUM_23, GPIO_MODE_INPUT);

    while (1)
    {
        if (gpio_get_level(GPIO_NUM_23))
        {
            if (count < 9)
            {
                count += 1;
            }
            else
            {
                count = 0;
            }
        }
        else
        {
        }

        for (int i = 0; i < 7; i++)
        {
            gpio_set_level(seven_seg_pins[i], numbers[count][i]);
        }
        vTaskDelay(30);
    }
}

Let’s break down the provided code snippet and explain each section, highlighting the key functions and their purpose:

#include <stdio.h>
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

These lines include necessary libraries and headers:

• <stdio.h>: The standard input/output library in C, which provides functions like printf.
• "driver/gpio.h": The header file used to work with GPIO (General Purpose Input/Output) pins on the ESP32.
• "freertos/FreeRTOS.h": The header file for using FreeRTOS (Real-Time Operating System) functions and features.
• "freertos/task.h": The header file specifically for managing tasks in FreeRTOS.

const int seven_seg_pins[7] = {GPIO_NUM_22, GPIO_NUM_21, GPIO_NUM_19, GPIO_NUM_18, GPIO_NUM_5, GPIO_NUM_4, GPIO_NUM_2};
const int numbers[10][7] = {{0, 0, 0, 0, 0, 0, 1}, {1, 0, 0, 1, 1, 1, 1}, {0, 0, 1, 0, 0, 1, 0}, 
{0, 0, 0, 0, 1, 1, 0}, {1, 0, 0, 1, 1, 0, 0}, {0, 1, 0, 0, 1, 0, 0}, {0, 1, 0, 0, 0, 0, 0}, 
{0, 0, 0, 1, 1, 1, 1}, {0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 1, 1, 0, 0}};

In this section, you define two arrays:

• seven_seg_pins[7]: This array contains the GPIO pin numbers used to control a seven-segment display. Each element represents a specific segment of the display.
• numbers[10][7]: This two-dimensional array stores patterns for displaying numbers (0-9) on the seven-segment display. Each row corresponds to a digit (0-9), and each column represents a segment of the display. For example, the pattern {1, 0, 0, 1, 1, 1, 1} corresponds to the number “1.”

int count = 0;

This line declares an integer variable count and initializes it to 0. This variable will be used to cycle through the numbers to display on the seven-segment display.

void app_main(void)

This line declares the app_main function, which serves as the entry point for our program running on the ESP32.

{
    for (int x = 0; x < 7; x++)
    {
        gpio_set_direction(seven_seg_pins[x], GPIO_MODE_OUTPUT);
    }

    gpio_set_direction(GPIO_NUM_23, GPIO_MODE_INPUT);

In this section, you configure the GPIO pins:

• for (int x = 0; x < 7; x++): This loop iterates through the seven_seg_pins array and sets the direction of each pin to GPIO_MODE_OUTPUT. These pins will control the segments of the seven-segment display.
• gpio_set_direction(GPIO_NUM_23, GPIO_MODE_INPUT);: This line configures GPIO pin number 23 as an input pin. This pin will be used to detect a button press or some other input event.

    while (1)
    {
        if (gpio_get_level(GPIO_NUM_23))
        {
            if (count < 9)
            {
                count += 1;
            }
            else
            {
                count = 0;
            }
        }
        else
        {
        }

        for (int i = 0; i < 7; i++)
        {
            gpio_set_level(seven_seg_pins[i], numbers[count][i]);
        }
        vTaskDelay(30);
    }
}

This is the main part of the code, which runs in an infinite loop (while (1)) and continuously monitors the state of GPIO pin 23 while controlling the seven-segment display based on the value of count.

• if (gpio_get_level(GPIO_NUM_23)): This condition checks the state of GPIO pin 23. If the pin is in a high (1) state, it means the condition is true, indicating that a button press or input event has occurred.
• Inside the if block, the code checks if count is less than 9. If it is, count is incremented by 1. If count reaches 9, it is reset to 0, allowing cycling through the numbers 0 to 9.
• The for loop then iterates through the segments of the seven-segment display. For each segment, it sets the corresponding GPIO pin’s state based on the pattern defined in the numbers array for the current count.
• vTaskDelay(30);: After setting the display segments, the code introduces a 30-millisecond delay using vTaskDelay(30);. This delay controls the display refresh rate and ensures that the numbers are displayed clearly.

Overall, this code controls a seven-segment display and cycles through the numbers 0 to 9 when a button press is detected on GPIO pin 23. The numbers array defines the segment patterns for each digit, and count keeps track of the currently displayed number.

DOWNLOAD FULL CODE

Using Menuconfig:

ESP-IDF’s menuconfig tool makes it easy to configure project settings. Access it with:

idf.py menuconfig

Here, you can customize various settings, including GPIO pin configurations and touch sensor settings.

Uploading and Testing Your Code:

Once your code is ready, it’s time to upload and test it on your ESP32 board. Follow these steps:

# Build the project
idf.py build

# Flash the project to your ESP32 board
idf.py -p PORT flash

Troubleshooting Tips

1. Driver Issues:

Problem: Your computer doesn’t recognize the ESP32.

Solution: Visit the official Espressif website for ESP32 drivers and install them to ensure smooth communication between your computer and the ESP32.

2. Port Configuration:

Problem: You encounter issues while flashing your project (idf.py -p PORT flash).

Solution: Ensure you’ve specified the correct port for your ESP32. Typically, it’s /dev/ttyUSB0 on Linux or COMX on Windows. Double-check your port configuration to prevent flashing errors.

3. Permission Problems (Linux):

Problem: You face permission problems when accessing the serial port.

Solution: Add your user to the dialout group using the sudo usermod -aG dialout $USER command. Afterward, log out and log back in to apply the changes and resolve permission issues.

4. GPIO Pin Configuration:

Problem: Unexpected behavior in your project.

Solution: Double-check your GPIO pin configurations both in the menuconfig menu and your code. Small mistakes in pin configuration can lead to unexpected behavior.

5. Library or Dependency Errors:

Problem: Errors related to missing libraries or dependencies.

Solution: Ensure you’ve followed the ESP-IDF installation guidelines correctly. Make sure you’ve installed all the necessary libraries and dependencies as specified in the documentation to avoid errors in your project.

By organizing these troubleshooting tips with clear headings, readers can easily identify and address common challenges they might encounter during the setup and coding process, making their learning experience smoother and more productive.

Conclusion:

You’ve just embarked on an exciting journey into the world of touch sensors and seven-segment displays with ESP-IDF. With this newfound knowledge, you’re well-equipped to create innovative IoT projects and take significant strides toward becoming a pro in the realm of Python and IoT. So, go ahead, tinker, experiment, and bring your ideas to life. The world of embedded systems awaits your creative genius! 🚀🔌

Also, check out our other playlist Rasa Chatbot, Internet of things, Docker, Python Programming, MQTT, Tech News, ESP-IDF etc.
Become a member of our social family on youtube here.
Stay tuned and Happy Learning. ✌🏻😃
Happy tinkering! ❤️🔥