FilippoOnesti
Published

ESP8266 Clock Using MAX7219 LED Matrix Display

A simple connected clock and weather report using ESP8266, MAX7219 LED matrix display, and DHT11 temperature and humidity sensor.

IntermediateFull instructions provided1 hour11,953
ESP8266 Clock Using MAX7219 LED Matrix Display

Things used in this project

Hardware components

ESP8266 NodeMCU
×1
MAX7219 LED Matrix Display
×1
DHT11 Temperature & Humidity Sensor (4 pins)
DHT11 Temperature & Humidity Sensor (4 pins)
×1
Photo resistor
Photo resistor
×1
Breadboard (generic)
Breadboard (generic)
×1
Jumper wires (generic)
Jumper wires (generic)
×1

Software apps and online services

Arduino IDE
Arduino IDE

Story

Read more

Schematics

Clock_Schematics.png

Code

Clock_Code.ino

C/C++
#include <ESP8266WiFi.h>
#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Max72xxPanel.h>
#include <time.h>
#include "DHT.h"

int pinCS = D4; 
int numberOfHorizontalDisplays = 4;
int numberOfVerticalDisplays   = 1;
char time_value[20];

// LED Matrix Pin -> ESP8266 Pin
// Vcc            -> 3v  (3V on NodeMCU 3V3 on WEMOS)
// Gnd            -> Gnd (G on NodeMCU)
// DIN            -> D7  (Same Pin for WEMOS)
// CS             -> D4  (Same Pin for WEMOS)
// CLK            -> D5  (Same Pin for WEMOS)

Max72xxPanel matrix = Max72xxPanel(pinCS, numberOfHorizontalDisplays, numberOfVerticalDisplays);

int wait = 70; // In milliseconds

int spacer = 1;
int width  = 5 + spacer; // The font width is 5 pixels

int m;

#define DHTPIN 0          // D3

#define DHTTYPE DHT11     // DHT 11

DHT dht(DHTPIN, DHTTYPE);

String t, h;

void setup() {
  Serial.begin(9600);
  dht.begin();
 
  //INSERT YOUR SSID AND PASSWORD HERE

  WiFi.begin("YOUR_SSID","YOUR_PASSWORD");

  //CHANGE THE POOL WITH YOUR CITY. SEARCH AT https://www.ntppool.org/zone/@
  
  configTime(0 * 3600, 0, "it.pool.ntp.org", "time.nist.gov");
  
  setenv("TZ", "GMT-1BST",1);
  
  matrix.setIntensity(0); // Use a value between 0 and 15 for brightness
  matrix.setRotation(0, 1);    // The first display is position upside down
  matrix.setRotation(1, 1);    // The first display is position upside down
  matrix.setRotation(2, 1);    // The first display is position upside down
  matrix.setRotation(3, 1);    // The first display is position upside down
  matrix.fillScreen(LOW);
  matrix.write();
  
  while ( WiFi.status() != WL_CONNECTED ) {
    matrix.drawChar(2,0, 'W', HIGH,LOW,1); // H
    matrix.drawChar(8,0, 'I', HIGH,LOW,1); // HH  
    matrix.drawChar(14,0,'-', HIGH,LOW,1); // HH:
    matrix.drawChar(20,0,'F', HIGH,LOW,1); // HH:M
    matrix.drawChar(26,0,'I', HIGH,LOW,1); // HH:MM
    matrix.write(); // Send bitmap to display
    delay(250);
    matrix.fillScreen(LOW);
    matrix.write();
    delay(250);
  }
}

void loop() {
  m = map(analogRead(0),0,1024,0,12);
  matrix.setIntensity(m);
  matrix.fillScreen(LOW);
  time_t now = time(nullptr);
  String time = String(ctime(&now));
  time.trim();
  //Serial.println(time);
  time.substring(11,19).toCharArray(time_value, 10); 
  matrix.drawChar(2,0, time_value[0], HIGH,LOW,1); // H
  matrix.drawChar(8,0, time_value[1], HIGH,LOW,1); // HH  
  matrix.drawChar(14,0,time_value[2], HIGH,LOW,1); // HH:
  matrix.drawChar(20,0,time_value[3], HIGH,LOW,1); // HH:M
  matrix.drawChar(26,0,time_value[4], HIGH,LOW,1); // HH:MM
  matrix.write(); // Send bitmap to display
       
  delay(30000);
      
  matrix.fillScreen(LOW);
  h = (String)(int)dht.readHumidity();
  t = (String)(int)dht.readTemperature();
  display_message(t+"C "+h+"%");
}

void display_message(String message){
   for ( int i = 0 ; i < width * message.length() + matrix.width() - spacer; i++ ) {
    //matrix.fillScreen(LOW);
    int letter = i / width;
    int x = (matrix.width() - 1) - i % width;
    int y = (matrix.height() - 8) / 2; // center the text vertically
    while ( x + width - spacer >= 0 && letter >= 0 ) {
      if ( letter < message.length() ) {
        matrix.drawChar(x, y, message[letter], HIGH, LOW, 1); // HIGH LOW means foreground ON, background off, reverse to invert the image
      }
      letter--;
      x -= width;
    }
    matrix.write(); // Send bitmap to display
    delay(wait/2);
  }
}

Credits

FilippoOnesti

FilippoOnesti

1 project • 0 followers
Computer Engineering Student in Ferrara, Italy. Arduino | Raspberry | IoT Python, Java, HTML, CSS

Comments