ESP32 with Adafruit Medium RGB Matrix Panel


I find it very interesting, using the Adafruit Medium RGB Matrix Panel (16×32 Pixel) with the ESP32. Unfortunately, until now, the Adafruit libraries did not support the ESP32 for driving the Matrix Panel.
Therefore I started migrating the Adafruit RGB-Matrix-Panel library to support the ESP32 as well.


At first I’ll look into the hardware connection between the ESP32 Development Kit and the RGB Matrix Panel. Adafruit describes the connection using jumper wires in their blog. Unfortunately, we cannot use this easy type of connection as the RGB matrices expect 5V I/O voltage and the ESP32 does only deliver 3.3V.

I’ve tested using 3.3V I/O Voltage to drive the RGB Matrix but it did not show the pictures clearly. For this reason, we will build an I/O level shifter board to connect the RGB Matrix and the ESP32 Development Board.

You can find very interesting hints on building prototype boards on

Level Shifter

To build the level shifter, we need the following materials.


IC174AC244N74AC244NDIL20Octal BUFFER and LINE DRIVER, 3-state
IC274AC244N74AC244NDIL20Octal BUFFER and LINE DRIVER, 3-state
PCB125x15 points (full count)PUNKTRASTER 254PUNKTRASTER
X2MKDSN1,5/2-5,08MKDSN1,5/2-5,08MKDSN1,5/2-5,08MKDSN 1,5/ 2-5,08 Printklemme


The following picture shows the schematic for the level shifter board.

Level Shifter Schematic
Schematic Level Shifter

And additionally, we will use the board as power distribution unit for the matrix and the development board using the following schematic.

Schematic power source
Schematic power source

Board Layout

The Top Side Layout and Bottom Side Layout as PDFs to enable “print to scale”.

To make the soldering as easy as possible, we created a very lean board layout.

Layout Level Shifter Top Side
Top side layout level shifter

These two pictures show the top and bottom layout of the level shifter board. Even beginners should be able to correctly solder this board.


Board photographs

At first, we placed the components onto the board as shown in this picture and soldered one point to fix the components.

Level shifter board top side
Level shifter board top side component placement

To make the connection easier, we bend the pins of the level shifter chips to the outside, so that we can directly solder them to the pin headers.

level-shifter pre-soldering pic
Establish contact before soldering

After that, we solder the pins together and finish with connecting the power leads using silver wire. At the end, it should look like in the following two pictures.


Finished level shifter board top side
Finished level shifter board top side


Finished level shifter board bottom side
Finished level shifter board bottom side

Connecting ESP32 and RGB Matrix using Level Shifter board

The following diagram shows the required connections between the ESP32 board, the level shifter board and the RGB Matrix Panel. Additionally, you need to connect the power cable of the Matrix panel to the screw terminals of the level shifter board and the barrel jack connector of the 5V power supply to the level shifter board.

Matrix Panel Wiring Diagram
Matrix Panel Wiring Diagram

The following table shows the resulting pin to pin definitions.

ESP32 GPIOLevel Shifter InputLevel Shifter OutputRGB Matrix Pin


We use the Arduino IDE and the Adafruit RGB Matrix Panel Library to drive the Matrix Panel. The Adafruit GFX Library is used to easily draw graphics on the panel.

Install IDE

At first, we install the Arduino IDE on your computer. Please download the Arduino IDE and install it according to your operating system. Download from

Install dependencies

We need a couple of libraries and the board support package to get started.


The easiest way to make your Arduino IDE compatible to the ESP32 is to use the board manager URL. Please copy the following URL:

Then open the Arduino IDE and go to “Preferences”. Then add the URL to the field “Additional Board Manager URLs”

Board Manager URL
Board Manager Setting

Next, click OK to close the Dialog.

Next, go to “Tools -> Board -> Boards Manager”. The Arduino IDE will not start to download the indexes from the board manager URLs and show the results to you.

Then search for “esp32” and install the resulting board support package by espressif.

ESP32 Board Manager
ESP32 Board Manager

After clicking “Install”, the IDE will download the BSP including compilers and toolchain. This may take some time.
But after that, you are able to compile and run sketches on your ESP32 board.

Adafruit GFX Library

Open the Library Manager from the Tools menu and search for the Adafruit GFX Library and click install.


Adafruit RGB Matrix Panel Library

Unfortunately, you cannot use the Library Manager to install the current version of this library that supports running the panel using the ESP32. Therefore we need to install the library manually using the current source code from GitHub.

Download the current source code as ZIP-file.

Extract the source into your Arduino-libraries folder in your documents folder.

Extract RGB Matrix Panel Library
Extract RGB Matrix Panel Library

After extraction, you need to restart the Arduino IDE, if it is currently running.

Code Example

To test your installation and hardware, you can use the plasma_16x32 example from the RGB Matrix Panel Library.

RGB Matrix Example
RGB Matrix Example

Before you upload the code to your device, you need to change the code to use the following definitions.

#define CLK 8
#define OE 9
#define LAT 10
#define A A0
#define B A1
#define C A2

RGBmatrixPanel matrix(A, B, C, CLK, LAT, OE, true);


#define CLK 4
#define OE   0
#define LAT 2
#define A   12
#define B   13
#define C   14

const uint8_t rgbpins[] = { 17,18,19,21,22,23 };
RGBmatrixPanel *matrix = new RGBmatrixPanel(A, B, C, CLK, LAT, OE, true, (uint8_t *)rgbpins);

Now, compile the code and upload it to your ESP32 and have fun!

Compile and upload
Compile and upload

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