The ESP32 contains a Serial Peripheral Interface Flash File System (SPIFFS). SPIFFS is a lightweight filesystem created for microcontrollers with a flash chip, which are connected by SPI bus, like the ESP32 flash memory. In this article we’re going to show how to easily upload files to the ESP32 filesystem using a plugin for the Arduino IDE.
Introducing SPIFFS
SPIFFS lets you access the flash memory like you would do in a normal filesystem in your computer, but simpler and more limited. You can read, write, close, and delete files. At the time of writing this post, SPIFFS doesn’t support directories, so everything is saved on a flat structure.
Using SPIFFS with the ESP32 is specially useful to:
- Create configuration files with settings;
- Save data permanently;
- Create files to save small amounts of data instead of using a microSD card;
- Save HTML and CSS files to build a web server;
- And much more.
In most of our web server projects, we’ve written the HTML code for the web server as a String directly on the Arduino sketch. With SPIFFS, you can write the HTML and CSS in a separated file and save them on the ESP32 filesystem. Check the following tutorial to learn how to build a web server with files stored on the ESP32 file system:
Installing the Arduino ESP32 Filesystem Uploader
You can create, save and write files to the ESP32 filesystem by writing the code yourself on the Arduino IDE. This is not very useful, because you’d have to type the content of your files in the Arduino sketch.
Fortunately, there is a plugin for the Arduino IDE that allows you to upload files directly to the ESP32 filesystem from a folder in your computer. This makes it really easy and simple to work with files. Let’s install it.
First, make sure you have the latest Arduino IDE installed, and you have the ESP32 add-on for the Arduino IDE. If you don’t, follow one of the following tutorials to install the add-on:
Follow the next steps to install the filesystem uploader:
1) Go to the releases page and click the ESP32FS-v01.zip file to download.
2) Go to the Arduino IDE directory, and open the Tools folder.
3) Unzip the downloaded .zip folder to the Tools folder. You should have a similar folder structure:
<home_dir>/Arduino-<version>/tools/ESP32FS/tool/esp32fs.jar
4) Finally, restart your Arduino IDE.
Note: the latest instructions can also be found here: https://github.com/me-no-dev/arduino-esp32fs-plugin
To check if the plugin was successfully installed, open your Arduino IDE. Select your ESP32 board, go to Tools and check that you have the option “ESP32 Sketch Data Upload“.
Uploading Files using the Filesystem Uploader
To upload files to the ESP32 filesystem follow the next instructions.
1) Create an Arduino sketch and save it. For demonstration purposes, you can save an empty sketch.
2) Then, open the sketch folder. You can go to Sketch > Show Sketch Folder. The folder where your sketch is saved should open.
3) Inside that folder, create a new folder called data.
4) Inside the data folder is where you should put the files you want to be saved into the ESP32 filesystem. As an example, create a .txt file with some text called test_example.
5) Then, to upload the files, in the Arduino IDE, you just need to go to Tools > ESP32 Sketch Data Upload.
Note: in some ESP32 development boards you need to keep the ESP32 on-board “BOOT” button pressed while it’s uploading the files. When you see the “Connecting …….____……” message, you need to press the ESP32 on-board “BOOT” button.
When you see the message “SPIFFS Image Uploaded“, the files were successfully uploaded to the ESP32 filesystem.
Testing the Uploader
Now, let’s just check if the file was actually saved into the ESP32 filesystem. Simply upload the following code to your ESP32 board.
After uploading, open the Serial Monitor at a baud rate of 115200. Press the ESP32 “ENABLE” button. It should print the content of your .txt file on the Serial Monitor.
You’ve successfully uploaded files to the ESP32 filesystem using the plugin.
Wrapping Up
Using the filesystem uploader plugin is one of the easiest ways to upload files to the ESP32 filesystem. Check the following project to see how to build a web server using HTML and CSS files stored on the filesystem: ESP32 Web Server using SPIFFS (SPI Flash File System).
For more projects with ESP32, check the following tutorials:
This is an excerpt from our course: Learn ESP32 with Arduino IDE. If you like ESP32 and you want to learn more, we recommend enrolling in Learn ESP32 with Arduino IDE course.
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