Tutorial Arduino ITA 31: display a matrice 8×8 con il LED driver MAX7219

Understanding the Display

The sketch to display animations will also show how to control the display with a simple gesture. A matrix display is nothing more than a set of many small LEDs. Thanks to the matrix structure, the number of pins needed to control them can be reduced to a minimum. In fact, with an 8×8 display composed of 64 LEDs, only 16 are needed, but as you will see below, you can further reduce it to only three pins using a MAX7219 LED driver. Alternatively, you can also use special modules in which the LED driver is already integrated. In this video, however, we will not use them to show you how to connect the display to the integrated circuit and what connections are hidden inside the module.

Pin Layout

The pin layout is quite intuitive: one half corresponds to the rows and the other half to the columns. It is less intuitive, however, for the order in which the pins are arranged, as they do not follow any logic. The various rows and columns are practically scattered randomly over all 16 pins. For this reason, it is extremely important to have the schema at hand. Another important thing to know is that not all LEDs are oriented in the same direction. Generally, when the code ends with 88AS, the cathode of each LED is connected to its respective row pin, while the anode is connected to the column. If the code ends with 88BS, all the LEDs are inverted and, consequently, the connections must also be inverted. In this case, the cathode is connected to the column and the anode to the row.

Connecting the Display to the Integrated Circuit

Once you have understood how the pins are arranged and how the LEDs are oriented, you can start connecting the display to the integrated circuit. First, connect the VCC pin of the display to the 5V pin of the Arduino and the GND pin to the GND pin. Then connect the DIN pin of the display to the digital pin 11 of the Arduino, the CS pin to the digital pin 10 and the CLK pin to the digital pin 9. Finally, connect the VCC pin of the integrated circuit to the 5V pin of the Arduino and the GND pin to the GND pin.

Writing the Code

To write the code, you will need to include the LedControl library. This library allows you to control the LED driver MAX7219. To do this, you must first create an object of type LedControl and then call the begin method. This method initializes the LED driver and sets the brightness of the display. You can then use the setLed method to turn on and off the LEDs. This method takes three parameters: the row, the column and the state of the LED. Finally, you can use the clearDisplay method to turn off all the LEDs.

I PIN di Arduino in modo da poter caricare, il nostro sketch sulla scheda

Utilizzare un LED Driver

Un LED driver un dispositivo che consente di controllare l’intensit luminosa di un LED. Il driver MAX7219 uno dei pi comuni e pu essere utilizzato per controllare una matrice 8×8 di LED. Il driver MAX7219 un circuito integrato che pu essere collegato direttamente ad Arduino, consentendo di controllare la matrice 8×8 di LED senza l’utilizzo di resistori.

Collegamenti

Per collegare il driver MAX7219 alla matrice 8×8 di LED, necessario scambiare le righe con le colonne. Gli anodi dei LED devono essere collegati ai pin sulla destra del circuito integrato, mentre i catodi devono essere collegati ai pin sulla sinistra. La prima colonna corrisponde al segmento DP, mentre le successive ai segmenti da A alla G. Le righe, invece, devono essere collegate ai pin Digit da 0 a 7. Se si utilizza un display dove i LED hanno polarit invertita, necessario scambiare le righe con le colonne.

Alimentazione

Una volta collegato il driver MAX7219 alla matrice 8×8 di LED, necessario alimentare il circuito. Per farlo, necessario portare sulla breadboard i pin 5V e GND. Inoltre, necessario aggiungere un condensatore da 47 microfarad, assicurandosi che il piedino contrassegnato con la banda scura sia collegato al GND.

Caricare lo Sketch

Una volta effettuati tutti i collegamenti, possibile caricare lo sketch sulla scheda Arduino. Per maggiori dettagli, possibile riguardare il video sul display a sette segmenti con quattro cifre, dove stato gi utilizzato lo stesso circuito integrato.

Il numero del led driver che stiamo utilizzando e come secondo parametro. Il valore da impostare ad esempio.

Utilizing the LED Driver MAX7219 to Display an 8×8 Matrix

The LED Driver MAX7219 is a powerful tool for displaying an 8×8 matrix. It is a versatile device that can be used to create a variety of visual effects and animations. In this tutorial, we will discuss how to connect the LED Driver MAX7219 to an Arduino board and use it to display an 8×8 matrix.

Connecting the LED Driver MAX7219

The first step in setting up the LED Driver MAX7219 is to make the necessary connections. The connections should be made in such a way that they do not obstruct the view during filming. All of the lower pins of the display should be connected to the top. It may take some patience to complete the circuit since there are many connections to be made. However, it is possible to simplify the circuit by using a display module with an integrated LED Driver MAX7219. In either case, the same sketches can be used since the pins on the Arduino board remain the same.

Installing the Library

The next step is to install the library for the LED Driver MAX7219. This can be done by going to the Library Manager and searching for LED Control. Once the library is installed, it can be included in the sketch. The three pins of the LED Driver MAX7219 should be specified, and an object of the class LED Control should be created. The first three parameters are the digital input, clock, and load pins, while the last parameter specifies the number of LED Drivers connected.

Setting Up the LED Driver

The setup function should be used to activate the LED Driver MAX7219 and set the brightness. It should also be used to clear the screen. All of the methods of the LED Control object should be passed the number of the LED Driver being used as the first parameter, and the value to be set as the second parameter.

Displaying Animations

Once the setup is complete, animations can be displayed on the screen. This can be done by using the setRow and setColumn methods of the LED Control object. The setRow method takes two parameters: the row number and the value to be set. The setColumn method takes three parameters: the column number, the row number, and the value to be set.

The LED Driver MAX7219 is a powerful tool for displaying an 8×8 matrix. It can be used to create a variety of visual effects and animations. In this tutorial, we discussed how to connect the LED Driver MAX7219 to an Arduino board and use it to display an 8×8 matrix. We also discussed how to install the library and set up the LED Driver MAX7219. Finally, we discussed how to display animations on the screen.

Overview

This tutorial provides a comprehensive guide to using the MAX7219 LED driver to display a 8×8 matrix. It explains how to interact with the display, how to use the set LED, set row and set column methods to animate the display, and how to use an array of bytes to store and display symbols.

Interacting with the Display

The simplest way to interact with the display is to use the set LED method. This requires four parameters: the index of the LED driver, the coordinates of the LED from top left, and a boolean value to specify whether the LED should be turned on or off. In this example, the index of the LED driver is always zero. The brightness can be adjusted from 0 to 15, with 15 being the brightest.

Animating the Display

The loop function is used to animate the display. It calls several functions to execute the animations. The inner for loop is used to turn on eight LEDs with different coordinates. The outer for loop is used to turn on the LEDs in the first iteration and turn them off in the second iteration, making the animation visible. After each turn on or off, a small delay is added.

Controlling Rows and Columns

The library also provides the ability to control entire rows or columns at once. The set row method is used to manage rows, while the set column method is used to manage columns. Both methods require four parameters: the index of the LED driver, the row or column to be changed, and a byte where each bit represents a single LED of the row or column in question.

Displaying Symbols

The set row method also provides an easy way to draw symbols or letters. An array of bytes is used to store the symbols, where each bit corresponds to the single LED of a row. With a multi-dimensional array, more than one symbol can be stored, each composed of 8 bytes (8 rows with 8 LEDs each). To display a symbol, the rows are scanned one by one to form the entire symbol. Since the loop is executed three times, but only two images are stored, the modulo is added to make sure that once the images are finished, the scan will start again from the beginning.

The MAX7219 LED driver is a powerful tool for displaying matrices of 8×8 LEDs. This tutorial will explain how to use the driver to display matrices of 8×8 LEDs.

Setting Up the MAX7219

The MAX7219 LED driver is a versatile device that can be used to control matrices of 8×8 LEDs. To set up the MAX7219, first connect the power supply and ground pins to the Arduino board. Then, connect the data pins of the MAX7219 to the Arduino board.

Writing the Code

Once the MAX7219 is connected to the Arduino board, it is time to write the code. The code is written in the Arduino IDE and consists of two parts: the initialization code and the display code.

The initialization code sets up the MAX7219 and configures it to display matrices of 8×8 LEDs. The display code is used to display the matrices of 8×8 LEDs.

Displaying the Matrices

Once the MAX7219 is set up and the code is written, it is time to display the matrices of 8×8 LEDs. To do this, the code must be uploaded to the Arduino board. Once the code is uploaded, the matrices of 8×8 LEDs will be displayed.

Using an Array to Store Images

Rather than writing code for each individual image, it is possible to store images in an array. This allows for multiple images to be stored in a single array and displayed in sequence. To do this, each image must be stored as a 64-bit integer, with each bit corresponding to a single LED in the 8×8 matrix.

Adding Interactivity

To make the content displayed on the 8×8 matrix more interactive, a gesture sensor can be used. The gesture sensor can be used to detect light, colour and proximity. By using the gesture sensor, the content displayed on the 8×8 matrix can be made more interactive.

Hardware

This tutorial focuses on the display of a 8×8 matrix with the LED driver MAX7219. The circuit for this tutorial consists of an Arduino Uno, a MAX7219 LED driver, a 8×8 LED matrix, and a APDS9960 gesture sensor. The LED driver is connected to the Arduino Uno via the SPI interface. The APDS9960 is connected to the Arduino Uno via the I2C interface.

Software

In this tutorial, we will need to install two libraries: one for the LED driver and one for the gesture sensor. To install the LED driver library, we can search for the “MAX7219” library in the Library Manager and install it. For the gesture sensor, we can search for the “APDS9960” library in the Library Manager and install the Adafruit library.

In the sketch, we need to specify the indices of the arrows to be displayed on the display. We also need to create an object to communicate with the gesture sensor. As seen in the previous example, we use an array of integers to store the symbols.

In the setup function, we add the initialization of the gesture sensor. In the loop function, we simply check if a gesture has been recognized. If so, we update the display using the switch construct. Since the gesture sensor is oriented upside down compared to the display, the direction of the arrows needs to be inverted compared to the movement detected by the sensor.

The function to display the images does not change, so we can load the symbols into the array and display them on the display.

This tutorial has explained how to use the MAX7219 LED driver to display matrices of 8×8 LEDs. It has also explained how to use an array to store images and how to add interactivity by using a gesture sensor. By following this tutorial, it is possible to create interactive displays using the MAX7219 LED driver.

In this tutorial, we have learned how to display a 8×8 matrix with the LED driver MAX7219 and the APDS9960 gesture sensor. We have installed the necessary libraries and specified the indices of the arrows to be displayed on the display. We have also created an object to communicate with the gesture sensor and inverted the direction of the arrows compared to the movement detected by the sensor. Finally, we have loaded the symbols into the array and displayed them on the display.