On this venture, we’ll study LED Matrix Shows and two completely different tasks on Arduino 8×Eight LED Matrix Interface. The primary venture will probably be an easy interface between Arduino and 8X8 LED Matrix to show data (even scrolling data and pictures may be displayed) and the second venture will probably be a complicated venture the place the 8×Eight LED Matrix is managed by way of an Android machine.
An LED matrix is a two-dimensional array of LEDs that can be utilized to show symbols, characters, and even pictures. Primarily based on the orientation of the LEDs within the matrix, there may be two forms of LED matrices. They’re Widespread Row Anode and Widespread Row Cathode.
Venture 1: Easy Arduino LED Matrix Interface
The venture relies on the Arduino Uno microcontroller board. Out of the 14 out there digital enter/output pins on the Arduino Uno, we’d like solely three pins to implement this venture.
One pin gives the clock sign to the LED show driver IC (MAX 7219) whereas one other pin is used to transmit the serial information to the IC for displaying on the LED matrix. The corresponding pins should be appropriately talked about in this system.
An Eight x Eight LED matrix show is used on this venture to show the data. LED matrices can be found in numerous kinds like single coloration, twin coloration, multi-color or RGB LED matrix.
They’re additionally out there in numerous dimensions like 5 x 7, Eight x 8, 16 x 16, 32 x 32 and so forth. Primarily based on the association of the LEDs within the matrix, an LED matrix may be both frequent row anode or frequent row cathode.
In case of frequent row anode kind LED matrix, the present sources (excessive or constructive voltage) are given to the rows A-D and the present sinks (low or adverse voltage or floor) are given to the columns 1-4.
In case of frequent row cathode kind LED matrix, the present sources (excessive or constructive voltage) are given to the columns 1-Four and the present sinks (low or adverse voltage or floor) are given to the rows A-D.
The LED matrix used on this venture is a standard row cathode kind LED matrix. Whereas creating the venture, the kind of LED matrix should be identified and this system should be written accordingly.
IC MAX 7219
The LED matrix may be pushed in two methods. They’re parallel (the place every row or column are despatched with parallel information) and serial (the place the info is distributed serially and an IC is used to transform this serial information into parallel information).
MAX 7219 is a standard cathode show driver with serial enter and parallel output. It’s used to interface microprocessors and microcontrollers with 64 particular person LEDs (Eight x Eight LED matrix, for instance, has 64 LEDs), seven-phase LED shows as much as Eight digits or bar graph shows.
The Eight x Eight LED matrix is linked to the MAX 7219 as proven within the circuit diagram and the info enter is acquired from the Arduino board to the MAX 7219.
Pre-wired MAX 7219 and eight x Eight LED matrix modules can be found out there. They can be utilized for comfort.
The intention of the venture is to interface an Arduino Uno board with an Eight x Eight LED matrix to show data.
Though a single Eight x Eight LED matrix with corresponding MAX 7219 IC is used on this venture, a number of LED matrices may be linked in the collection for lengthy scrolling show. Join the elements as proven within the circuit diagram. The working of the system is as follows.
three of the 14 out there digital enter/output pins are used to manage the show driver IC MAX 7219. The three pins on the MAX7219 IC are the clock, information in and cargo (or cs in case of MAX 7221 IC). The most clock frequency of 10MHz may be utilized. DIN (Knowledge in) accepts the serial information from the microcontroller or Arduino board.
It’s 16 bit lengthy the place the primary Eight bits (D0 – D7) are for driving the columns (SEG A-G and DP of the MAX 7219 IC) of the LED matrix and the subsequent Eight bits (D8 – D15) are for driving the (DIG 0-7 of the MAX 7219 IC) rows of the LED matrix.
The load pin (or CS or chip choose pin in case of Max 7221 IC) latches the serial enter information on its rising edge.
One other vital pin on MAX 7219 is the ISET, which units the height present to the phase to drive all of the LEDs. It’s linked by way of a resistor (R1), which known as RSET. The capacitors filter out any noise within the provisions.
When the serial information in is distributed utilizing the Arduino (by way of this system), the serial information is transformed into segments and digits to drive columns and rows of the LED matrix. Based on the info despatched, the corresponding LEDs on the matrix gentle up and show the message.
This system written right here is for scrolling textual content show. It could be troublesome to view lengthy scrolling information on a single Eight x Eight LED matrix. Therefore, a number of LED matrices may be chained to kind a protracted matrix.
The no. of MAX 7219 ICs are equal to the no. of Eight x Eight LED matrices. With a view to prolonging the show to a number of LED matrices, the Knowledge OUT (DOUT) pin of the primary MAX 7219 should be linked to the Knowledge IN (DIN) pin of the second MAX 7219 IC. This course should be continued for a number of LED matrices.
(The positioning of the LED Matrix within the chain is vital. The primary LED matrix should be positioned on the proper of the chain.)
- This system makes use of a library referred to as LedControl. This library should be added to the Arduino IDE and the header file LedControl.h should be included in this system.
- The usage of this library file is to allow a number of MAX 7219 ICs to be built-in and in addition present scrolling textual content.
Venture 2: Arduino 8X8 LED Matrix Interface with Android Cellphone
The second circuit within the Arduino 8×Eight LED Matrix Interface collection relies on Bluetooth Communication and Android Cellphone. On this venture, now we have interface Arduino with an Android cellphone utilizing Bluetooth Communication and the 8×Eight LED Matrix linked to Arduino by way of MAX7219 is managed by way of a devoted utility on the Android Cellphone.
We now have already seen within the earlier venture as for how the 8×Eight LED Matrix and the MAX7219 IC are linked. So, I’ll skip that a part of the connection and proceed with how MAX7219 IC is interfaced with Arduino.
However, I haven’t talked about the Pin Diagram of a typical 8×Eight LED Matrix within the earlier circuit. So, to have fulfillment, the next picture reveals the pinout of an 8×Eight LED Matrix.
As you possibly can observe, an 8×Eight LED Matrix consists of 16 pins: Eight Rows and eight Columns. Normally, the Rows are related to the Anodes of the LEDs and the Columns are related to the Cathodes of the LEDs.
- Arduino UNO
- MAX7219 IC Board
- 8×Eight LED Matrix
- HC-05 Bluetooth Module
- Android Cellphone with App put in
For the reason that communication between Arduino and MAX7219 relies on SPI Communication Protocol, all we’d like is three pins from Arduino (Knowledge, Clock and Chip Choose). The CS, CLK and DIN pins of the MAX7219 IC Board are linked to pins 10, 11 and 12 of the Arduino.
As we’re utilizing the Bluetooth connection between Arduino and Android machine, the RX and TX pins of the HC-05 Bluetooth Module are linked to TX and RX pins of the Arduino (Pins 1 and 0).
Controlling 8×Eight LED Matrix by way of Android App
A devoted app for Android primarily based gadgets is designed for this venture. The structure of the app which is already put in on a cell phone is proven within the following picture.
The app has 8×Eight squares (every corresponding to 1 LED on the 8×Eight LED Matrix), a Reset button and a Disconnect button. Touching a selected sq. will flip ON the actual LED within the 8×Eight LED Matrix.
The color of the sq. will flip Crimson, as a sign that the LED is turned ON. Touching the sq. as soon as once more will flip OFF the corresponding LED and the color of the sq. will revert again to gray.
A Reset button is given on the backside, utilizing which you’ll be able to reset the 8×Eight LED Matrix i.e. all of the LEDs will probably be turned OFF. The disconnect button will get disconnected from the Bluetooth.
NOTE: The app makes use of the Bluetooth characteristic of the cellphone. Therefore, obligatory permissions should be given. Additionally, the HC-05 Bluetooth Module should be paired with the machine (Cellphone).
Obtain Android App
You possibly can obtain and set up the App used on this venture for Android Gadgets. Use this hyperlink to put in the App.
- Arduino primarily based Eight x Eight LED matrix show makes use of solely three pins of the Microcontroller. Therefore, it may be utilized in functions the place displaying data is part of the system through which different pins of the microcontroller can be utilized for different peripherals.
- LED Matrix is a primary type of show machine that’s used for displaying data at public locations like bus or practice stations.
- A number of LED matrices may be mixed to kind giant shows and can be utilized to show pictures with multi colors.