DevDigest

Running Python scripts automatically on boot is a powerful feature for many ESP32-based projects. Whether you’re working on IoT applications, home automation, or other embedded systems, automating script execution right from the start allows your device to be ready to use without manual intervention. The ESP32 is a versatile microcontroller that can run MicroPython, an efficient implementation of Python, enabling seamless integration with your projects. In this article, we’ll guide you through the process of configuring your ESP32 to automatically run a Python script as soon as it powers up, providing an efficient and hands-off experience for your embedded systems.

By setting up the boot.py and main.py files, you can control what happens during the boot process. The boot.py file is executed first and can be used to configure initial settings, like connecting to Wi-Fi. The main.py file will run afterward and contains the main logic of your program. Once these files are set up, your ESP32 will automatically run your desired Python script on boot, enabling you to focus on developing the core features of your project rather than manual startup processes.

Table of Contents

Understanding the Boot Process on ESP32

When your ESP32 powers on, it goes through a boot process, where it loads the firmware and waits for further commands. By default, the ESP32 does not run any scripts automatically. However, by configuring your ESP32 with MicroPython, you can set it up to run Python scripts on boot using the boot.py and main.py files.

The boot.py file is executed first during boot, followed by the main.py file. You can modify or create these files to automate various tasks, such as setting up Wi-Fi, initializing peripherals, or running custom scripts immediately upon boot.

How to Set Up Your ESP32 to Run Python Scripts on Boot

Install MicroPython on Your ESP32

To start programming with the ESP32, you’ll need to set up the development environment. This involves installing the Arduino IDE, adding the ESP32 board through the Board Manager, and setting up necessary drivers for the microcontroller.
Find detailed steps on setting up the development environment here.

Create boot.py for Initial Setup

The boot.py file is executed as soon as the ESP32 starts up. Use this file to handle initial configurations, such as setting up Wi-Fi or loading essential libraries. For example, here’s a simple boot.py that prints a “Hello, World!” message when the device starts:

# boot.py
boot.py print("Hello, World!") 

This message will be printed to the console immediately upon boot.

Create main.py for Your Core Script

After the ESP32 runs boot.py, it will then run the main.py file. This is where the main functionality of your application resides. You can place the core logic of your project, such as sensor readings, device control, or communication, in this file.Example of a simple main.py script:

# main.py
def greet():
    print("This is from main.py!")

greet()

Import main.py into boot.py to Run on Boot

To keep your code modular and organized, you can import main.py into boot.py using the import keyword. This ensures that after printing the “Hello, World!” message, the ESP32 will load and execute main.py as part of the boot process.Here’s how boot.py should look:

# boot.py
print("Hello, World!")

# Import and run the greet function from main.py
import main

main.greet()

Save and Reboot Your ESP32

After saving both boot.py and main.py to your ESP32’s file system, reboot the device to see the changes take effect. You can reboot your ESP32 by running the following command in the REPL:

import machine
machine.reset()  # Reboots the ESP32

Test Your Setup

Upon reboot, your ESP32 will automatically run boot.py and print “Hello, World!” to the console. It will then import main.py and execute the greet() function, printing “This is from main.py!” as expected.

Troubleshooting Tips

• Ensure Correct File Placement: The boot.py and main.py files must be placed in the root directory of the ESP32’s file system. Files located in subdirectories won’t be executed on boot.
• Check for Code Errors: If the ESP32 doesn’t boot as expected, check the serial monitor for error messages. Simplifying your code can help you isolate the issue.
• Resetting the Device: If needed, you can always reset the ESP32 to its default state and modify the boot configuration again.

Conclusion

Running Python scripts on boot is an essential feature for automating your ESP32 projects. With just a few simple steps, you can configure your ESP32 to automatically run Python scripts as soon as it powers up, saving you time and effort. By modifying the boot.py and main.py files, you can easily handle initial configurations and execute your core application logic without manual intervention.