Arduino LED 8X8 DOT Matrix Display With MAX7219

The Dot Matrix display is so useful that every enthusiast once came across it. It is a two dimensional patterned LED array that is used to represent character, symbol and images. Almost every outdoor LED display uses a dot matrix.

Talking of controlling dot matrices, hardly anyone can find any better IC than MAX7219. This IC is so simple to use and very inexpensive which makes it more popular than others.

Supplies

Arduino UNO

LED Dot Matrix

Battery 9V

Step 1: About MAX7219 Module

There are many breakout boards available for MAX7219, but 2 of them are largely popular ona is the Generic module(the one we used in our project) and the other one is the FC-16 module.

Generally a MAX7219 module contains a 8x8 dot matrix and a MAX7219 LED driver. Let’s get familiar with each of them.

Step 2: Dot Matrix LED Display

There are 16 pins in a typical 8x8 LED Dot Matrix, 8 for each row and 8 for each column. Here all rows and columns are wired to reduce the total pin required. If this was not done then it would require a total of 65 pins to connect to a 8x8 led dot matrix 64 for the LEDs and 1 for the common Anode/Cathode. By doing this only 16 pins are required. The method of controlling a large number of LEDs through a few pins is called Multiplexing.

Step 3: MAX7219 IC

The main drawback of the multiplexing is, You have to keep on refreshing the display for stability.

Here comes the role of the MAX7219 IC. It will take care of everything, you just have to send commands to the 4 pin serial interface.

t is capable of controlling all the 64 individual LEDs maintaining the same brightness and we can also change the brightness.

Once the IC is updated by the Development board it will take of all the work refreshing the display at 800 Hz. As the MAX7219 IC communicates via SPI it only requires 3 pins. We can also control a number of dot matrices through these 3 pins.

Step 4: Pinout of MAX7219 Module

Whichever module we choose we get pins on both sides.

Step 5: Input Connection of MAX7219 Module

VCC Connects to +5 V

GND To the Common Ground.

DIN Data in Connects to any digital Pin.

CS/LOAD Chip Select, is connected to any digital pin.

CLK is the Clock pin, Connect it to any digital pin.

Step 6: Connection of MAX7219 Module With Arduino UNO

Now as we get familiar with the module, we start connecting it with our Development board(in our case it is an Arduino UNO). It is recommended to use an external power supply for the display as it drains much current but if you are experimenting with a single matrix then its OK(still external power supply recommended).

As it requires a lot of data transformation it will be better if we connect the SPI pins with the hardware SPI pins(vary from board to board, for reference do check the official site).

Step 7: Ordering PCB From JLCPCB

Ordering PCb from JLCPCB is quite simple and easy.

You just have to add your gerber file (max upto 6 layers) , select layer and add to cart then checkout securely and the sum. That's it no your designed PCB is at your doorstep.