LED Matrix With Arduino




Hola , I am Javier from Makespace Madrid. Last week we organised a meetup to play with LED matrixes and Arduinos. This was part of  "La noche de la electrónica con Jameco"
This instructable is based on the workshop. It uses one single LED matrix and shows how to switch its LEDs on/off and how to display ASCII characters.
A future instructable will show how to work with mulitple LED matrixes connected together.

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Step 1: Components

For this example, you need the following components:
- Arduino Uno board
- MAX7219 Red Dot Matrix Module
- 5 jumper wires F/M (female/male)

Although this instructable uses an Arduino Uno board, you can use other Arduino (compatible) boards

You can find the matrix module at many online stores (e.g. http://dx.com/p/max7219-dot-matrix-module-w-5-dupont-lines-184854). This includes a 8x8 LED matrix (red colour), a MAX7219 chip to control the LEDs, header PINs and sockets, one 10KOhm resistor, a 100nF capacitor, a 10uF electrolic capacitor and a PCB where everything is connected together. You can purchase the module already soldered and mounted or just the components. Up to you;-)

If you want to learn the low level details, you should check this article at arduino playground.

IMPORTANT: The LED matrix is common cathode. This module does not work with common anode matrixes.

Step 2: Arduino Library

The LED matrix is controlled from the MAX7219 chip through an Arduino Library.
This instructable is based on the LEDControl library. You can read a very clear and detailed tutorial about this library at arduino playground.
The nice thing about this library is that you can connect up to 8 matrixes together to build larger displays (more about this in a future instructable).

The LedControl library has been updated with several new methods to simplify the display of characters and strings. The new version of the library is available here (chose your preferred compression format: zip or rar)

To install the library in your Arduino IDE:
- uncompress the library file that you just downloaded
- make sure that you close all the open windows of the Arduino IDE
- look for the libraries folder inside the folder where you installed the Arduino IDE (see picture)
- copy the uncompressed LedControlMS folder (the folder with all its content)  inside the libraries folder

If everything worked fine, you can now open the Arduino IDE again. If you go to File-> Examples, there should be a tab named LedControlMS with four files inside it.

Step 3: Wiring

Once you have installed the library, it is time to connect the LED matrix to the Arduino board.

The LED Matrix module has two sets of male header PINs. In this instructable you will only use the input PIN headers that are located closer to the MAX 7219 chip.
There are five PINs that must be connected through F/M jumper wires to the corresponding Arduino PINs:

LED Matrix        Arduino         Colour of wire in picture
VCC                        5V                       Red
GND                       GND                   Black
DIN                         D12                    Yellow
CS                          D10                     White
CLK                        D11                     Blue

You can check the colours of the wires in the pictures in case that you have any doubt.

Step 4: Example Sketch

The original LedControl library can handle both 7-segments LED displays as well as LED matrixes. This instructable only uses the LED matrix methods.

The updated library created for the Makespace Madrid workshop defines an alphabet/font of characters that can be displayed in the LED matrixes. It also includes two new methods, writeString and displayChar. You can see practical examples of how the different methods work in the MakeSpace_LEDMatrix example sketch distributed with the library.
To open this sketch, in the Arduino IDE menu go to File-> Examples->LedControlMS->MakeSpace_ LEDMatrix

You can now upload the sketch to your arduino and see what the example does.

Note1: if the version of your Arduino IDE is "quite" old (0.x) you will need to change the extension of the arduino sketches distributed with the library. Change the extension of the files from .ino to .pde (MakeSpace_ LEDMatrix.ino -> MakeSpace_ LEDMatrix.pde). Your IDE should be able to read and open this file (probably you need to close all the Arduino IDE windows, change the file extensions and then restart the IDE again).

Note2: Before uploading the sketch, make sure that you have selected the right card and serial port for your arduino

Step 5: And Play!

If everything worked fine, your LED matrix will start a sequence of actions switching on and off leds and displaying different characters.
You can now map the code in the example sketch to the actions in the matirx. Update the sketch to do new things and experiment with  the library methods.

To help you, the PDF file below has some hints about how the LEDs, rows and columns are numbered and coded in the LEDControl library.
Don't be afraid to make errors! That is the fastest way to learn.


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80 Discussions


Question 1 year ago on Step 3

Does this work with arduino uno board?

I tried the code ,uploaded it and then all the leds glowed.But it didn't show up as shown in the video above


1 year ago

Hi Tumaku,,,nice post...
May I ask you for help, If I want to use 4 set dot matrix and want to display text character, which sketch must to change, please?

I want to use this char

PROGMEM const unsigned char CH[] = {

3, 8, B0000000, B0000000, B0000000, B0000000, B0000000, // space

1, 8, B1011111, B0000000, B0000000, B0000000, B0000000, // !

3, 8, B0000011, B0000000, B0000011, B0000000, B0000000, // "

5, 8, B0010100, B0111110, B0010100, B0111110, B0010100, // #



2 years ago

#define NBR_MTX 2 // Why do I have to say "2" when there is only 1 matrix in my setup?

1 reply

Reply 2 years ago

Thanks Malcolm for noticing this bug!

I used the same sketch for another project with multiple matrices and I forgot to set NBR_MTX back to "1". Anyway, since the code only references one matrix (the one with index "0") the sketch is still working without any problem.


Reply 2 years ago

There is a link in step 2 to compressed files in zip and rar format.


4 years ago on Introduction

I am only getting two leds showing at once. I have checked for bridges and there are none. Can anyone help me here?

4 replies

Reply 4 years ago on Introduction

I am now getting more LEDs on at once but no distinguishable letters.


Reply 2 years ago

Hello, Most probably you fixed the LED matrix on the wrong side of the PCB.
It might be soldered on the CHIP side of the PCB.


Reply 3 years ago

I had the same /similar problem. the reason was that the MAX7219 was wrong inserted. I just removed it and inserted it in the other way round. Then it works!


Reply 4 years ago on Introduction

Sorry for the late response.

Not sure what is wrong, but I suggest to check three points:

- Are you providing enough power (miliamps) to the matrix?

- Have you double/triple checked that the wires are properly connected?

- Are you using a common cathode matrix? (the code does not work if the matrix is common anode)


2 years ago

hi, can the max7129 be used for a dot matrix display with an Arduino pro Micro? If so, What would be suitable pin connections?

1 reply

Reply 2 years ago

I have used it with an Arduino ProMini so a ProMicro should also be ok. The pins in the instructable are defined as:
LED Matrix    Arduino          Colour of wire in picture
VCC               5V                   Red
GND              GND                Black
DIN                D12                 Yellow
CS                 D10                 White
CLK               D11                 Blue

You can remap them for your ProMicro by updating their values in the following line of the sketch:

LedControl lc=LedControl(12,11,10, NBR_MTX);


2 years ago

Hey Tumaku, thanks for your post! This helped me out a ton when I first started out with my 8x8 Matrix.

I've linked to your instructables in an INO I made to make it easier to animate moving animations on the MAX7219 8x8 LED Matrix. I think I need to comment more of the code here, but the basics are there.


Here's what the animation looks like (Sorry, it might be a little loud.)

1 reply

2 years ago

can i get code or any information for respective project ?

1 reply

Reply 2 years ago

Code and explanation is available in Step 2


2 years ago

can you give me sketch(coding) in arduino ? khuzzair@gmail.com :D Thanks