Team Synergya:

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Published November 11, 2022 © CC BY-NC-SA

LED Matrix 32x16 RGB & Ultrasonic Sensor

An art experiment with 2 x 16 x 16 RGB LED matrix that lights in random positions and colors when the ultrasonic sensor is triggered.

BeginnerFull instructions provided2,905

LED Matrix 32x16 RGB & Ultrasonic Sensor

Things used in this project

Hardware components

Arduino UNO Wifi Rev.2

Ultrasonic Sensor - HC-SR04 (Generic)

16x16 RGB LED Matrix WS2812B

5V 40A Power Supply

Jumper wires (generic)

Software apps and online services

Arduino IDE

Story

This is our first project with Arduino for the Digital Systems course in Computer Science graduation from Cesar School (Recife, Brazil).

Our final goal is to create a prototype of an Art Installation, a videowall made of a matrix of LED lights, creating an interactive panel of pixelated images that interacts with the public.

To achieve this goal, this is our first small step in the project: create a smaller version (32x16cm) led panel that randomly lights colorful pixels when the public walks in front of it, or interacts with the ultrasonic sensor.

1. Power SupplySetup

The 16x16 led matrix has 256 dots, since it is RGB, it has 768 leds with the typical 20mA each. So, all leds on max brightness will require 15.36A for just one matrix. Later, we concluded that we wouldn´t require even 50% of that power, and that it was easily manageable in code. Still, BE CAUTIOUS of the power supply that your project will require when dealing with led matrices and strips.

Leds usually works with 5V, same as the Arduino board.

First, the Arduino board won´t supply enough power for the leds, so you will need an external supply:

5V 40A 110-220V Power Supply

Then, connect the terminals:

PC Power Cord

Connect line, neutral and ground wires in the correct terminals:

(search about the wiring color codes, and double-check the indication signs)

5V 40A 110-220V Power Supply

Now, we need to power the LED matrix, as you can see on the photos below, we connected the 5V and a GND, in the middle, to the respective terminals of the power supply:

16x16 RGB LED Matrix WS2812B

5V 40A 110-220V Power Supply

2) LED Panels Setup

16x16 RGB LED Matrix WS2812B

Connect:

The LED Panel's data in (DIN--to--3) Arduino´s.
The LED Panel's ground (GND--to--GND) Arduino´s.
The LED Panel's power line (5v--to--5v) Arduino´s.

*You can power the Arduino board and peripherals with thesame powersupply using the extra 5V terminals that the ledpanel provides, or just connect the GND and power the board through the USB or another power supply.

** Also you can use the breadboard to better organize the power as you´llsee later below.

Arduino UNO

From here, we could start testing our code to control the LED panel, but first we are going to add a second LED panel:

Just connect the output terminal from one panel to the input of the other:

16x16 RGB LED Matrix WS2812B

3)UltrasonicSensorSetup

Ultrasonic Sensor (HC-SR04)

Connect:

Arduino UNO and Ultrasonic Sensor (HC-SR04)

Finally, put it all together:

Final setup

4)Prototype Structure

We made a really simple structure just for better handling and showing.

We used three 60x30cm MDF boards, designed a box in MakerCase and adapted in Adobe Illustrator to laser cut it in LOUCo / Porto Digital.

60x30cm MDF half-box made with a laser cutter

.ai archive is available below.

5) Code

We made use of Arduino IDE, FastLED library and Ultrasonic by Erick Simões library.

*We made a few tests with Adafruit´s NeoMatrix library, but wedidn´t use it in the code after all. We really recommend this library also, it works with FastLED and provides more features specificallyfor matrices. Since we are in a learning path, we decided to stick only to FastLED and keep it more simple and crude to better understandingthe principles.

We took some code samples and examples in fastLED´s github and Adafruit´s github, and with coberfranc´s instructables and HeathenHacks´ project.

More details in the code´s comments below.

Schematics

Code

SYNERGYALEDMATRIX32x16.ino

//SYNERGYA 32x16 
//LED MATRIX WITH ULTRASONIC SENSOR
//by Camila Cirne, Francisco Luz, Gislaine Reis, Pedro Coelho and Thiago Arajo

#include <Ultrasonic.h> // Add the Ultrasonic by Erick Simes' library
#include "FastLED.h" // Add FastLED library

#define NUM_LEDS 512 // set the number of LEDS (for 1 matrix 256, for 2 matrices 512 and so on...)
#define DATA_PIN 3 // set the pin number from the Arduino board
CRGB leds[NUM_LEDS];

const int someoneArrivedPin = 7;  // set the TRIG terminal in the Arduino board from the Ultrasonic sensor
const int someoneLeftPin = 6; // set the ECHO terminal in the Arduino board from the Ultrasonic sensor

void setup() {
  delay(2000);
  FastLED.addLeds<WS2812B, DATA_PIN, RGB>(leds, NUM_LEDS); // WS2812B is the matrix model were using
  FastLED.setBrightness(150); // Setup the general brightness (0-255)
  FastLED.clear();
  Serial.begin(9600); // Start the serial port to initialize the ultrasonic sensor
  pinMode(someoneArrivedPin, OUTPUT);  // set OUTPUT and INPUT accordingly to the ultrasonic sensor library
  pinMode(someoneLeftPin, INPUT);
}

Ultrasonic ultrasonic(someoneArrivedPin, someoneLeftPin);

int randomInt;
int randomInt2;

void loop() {
  for(int i = 0; i < 10; i++){ // Outerloop
    for(int j = 0; j < 1000; j++){ // TURN LEDS ON - Innerloop
        if (ultrasonic.read() > 10 and ultrasonic.read() <=100){ // Return the distance in cm in the if condition
          randomInt = (rand()%512); // random intenger that chooses the leds which will be turn on
          randomInt2 = (rand()%256); // random intenger that chooses the color Hue of the given leds
          leds[randomInt].setHue(randomInt2);
          FastLED.show();
        }
     } 
    for(int k = 512; k > 0; k--){ // TURN LEDS OFF - 2nd Innerlooop
      leds[k] = CRGB::Black;
      FastLED.show();
    }
  }
}

LED Matrix 32x16 RGB & Ultrasonic Sensor