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How to Control MAX7219 LED Matrix with ESP8266 WiFi Module

psadminetechpath — Sat, 02 Dec 2017 00:40:20 +0000

About this Project:
In this project we will learn how to interfacing ESP8266 module with MAX7219 matrix display to scrolling text message from web user interface. We will use Arduino IDE to program ESP module in this project. I am using MajicDesigns MD_MAX72xx library for running this project, also the code is very similar to included example in the library with some improvements in web user interface html code.

Components:

MAX7219 8×8 LED Matrix
ESP8266 Node MCU
USB Cable for programming and power

Circuit Diagram:

Steps:

1. 1. Connect the circuit as shown above.
  2. Install Arduino IDE form arduino website. After that install ESP8266 board and library in Arduino IDE.
  3. Download and install MD_MAX7219 Library from download section for driving MAX7219 matrix. For using this library you will need to edit MAX72xx.h file for configure the type of LED matrix you are using. In this project we are using FC-16 Chinese module.
  4. Download code ino file from download section and open it with Arduino IDE.
  5. You will need to edit WiFi network SSID and Password inside your code before flashing it in ESP module.
```
const char* ssid = "your SSID";                   // edit your wifi SSID here
const char* password = "your Password";            // edit your wifi password here
```
  6. Select board to NodeMCU and flash the code in ESP module.
  7. Power up the circuit and you will see IP address of your ESP module allocated by your WiFi network on Matrix display. (watch video)
1. Now open that IP address in any browser connected in same network. And you will see web user interface to enter text.
2. For detailed procedure of configuring WiFi module with your home network and using web interface, please watch embedded YouTube video linked at the bottom of this page.

Code:

//Link: https://blog.etechpath.com

#include 
#include 
#include 

#define	PRINT_CALLBACK	0
#define DEBUG 0
#define LED_HEARTBEAT 0

#if DEBUG
#define	PRINT(s, v)	{ Serial.print(F(s)); Serial.print(v); }
#define PRINTS(s)   { Serial.print(F(s)); }
#else
#define	PRINT(s, v)
#define PRINTS(s)
#endif

#if LED_HEARTBEAT
#define HB_LED  D2
#define HB_LED_TIME 500 // in milliseconds
#endif

#define	MAX_DEVICES	4

#define	CLK_PIN		D5 // or SCK
#define	DATA_PIN	D7 // or MOSI
#define	CS_PIN		D8 // or SS

// SPI hardware interface
//MD_MAX72XX mx = MD_MAX72XX(CS_PIN, MAX_DEVICES);
#define HARDWARE_TYPE MD_MAX72XX::PAROLA_HW  //edit this as per your LED matrix hardware type
MD_MAX72XX mx = MD_MAX72XX(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);
// Arbitrary pins
//MD_MAX72XX mx = MD_MAX72XX(DATA_PIN, CLK_PIN, CS_PIN, MAX_DEVICES);

// WiFi login parameters - network name and password
const char* ssid = "your SSID";                   // edit your wifi SSID here
const char* password = "your Password";            // edit your wifi password here

// WiFi Server object and parameters
WiFiServer server(80);

// Global message buffers shared by Wifi and Scrolling functions
const uint8_t MESG_SIZE = 255;
const uint8_t CHAR_SPACING = 1;
const uint8_t SCROLL_DELAY = 75;

char curMessage[MESG_SIZE];
char newMessage[MESG_SIZE];
bool newMessageAvailable = false;

char WebResponse[] = "HTTP/1.1 200 OK\nContent-Type: text/html\n\n";

char WebPage[] =
"" \
"" \
"" \
"eTechPath MAX7219 ESP8266" \
""\
"" \
"" \
"" \
""\
"WiFi MAX7219 LED Matrix Display" \ 
"" \
"Msg:

" \
"" \
"
" \
"" \
"Visit Us at" \ 
"www.eTechPath.com" \
"" \
"" \
"";

char *err2Str(wl_status_t code)
{
  switch (code)
  {
  case WL_IDLE_STATUS:    return("IDLE");           break; // WiFi is in process of changing between statuses
  case WL_NO_SSID_AVAIL:  return("NO_SSID_AVAIL");  break; // case configured SSID cannot be reached
  case WL_CONNECTED:      return("CONNECTED");      break; // successful connection is established
  case WL_CONNECT_FAILED: return("CONNECT_FAILED"); break; // password is incorrect
  case WL_DISCONNECTED:   return("CONNECT_FAILED"); break; // module is not configured in station mode
  default: return("??");
  }
}
uint8_t htoi(char c)
{
  c = toupper(c);
  if ((c >= '0') && (c <= '9')) return(c - '0');
  if ((c >= 'A') && (c <= 'F')) return(c - 'A' + 0xa);
  return(0);
}
boolean getText(char *szMesg, char *psz, uint8_t len)
{
  boolean isValid = false;  // text received flag
  char *pStart, *pEnd;      // pointer to start and end of text
  // get pointer to the beginning of the text
  pStart = strstr(szMesg, "/&MSG=");
  if (pStart != NULL)
  {
    pStart += 6;  // skip to start of data
    pEnd = strstr(pStart, "/&");
    if (pEnd != NULL)
    {
      while (pStart != pEnd)
      {
        if ((*pStart == '%') && isdigit(*(pStart+1)))
        {
          // replace %xx hex code with the ASCII character
          char c = 0;
          pStart++;
          c += (htoi(*pStart++) << 4);
          c += htoi(*pStart++);
          *psz++ = c;
        }
        else
          *psz++ = *pStart++;
      }
      *psz = '\0'; // terminate the string
      isValid = true;
    }
  }
  return(isValid);
}
void handleWiFi(void)
{
  static enum { S_IDLE, S_WAIT_CONN, S_READ, S_EXTRACT, S_RESPONSE, S_DISCONN } state = S_IDLE;
  static char szBuf[1024];
  static uint16_t idxBuf = 0;
  static WiFiClient client;
  static uint32_t timeStart;

  switch (state)
  {
  case S_IDLE:   // initialise
    PRINTS("\nS_IDLE");
    idxBuf = 0;
    state = S_WAIT_CONN;
    break;
  case S_WAIT_CONN:   // waiting for connection
    {
      client = server.available();
      if (!client) break;
      if (!client.connected()) break;
#if DEBUG
      char szTxt[20];
      sprintf(szTxt, "%03d:%03d:%03d:%03d", client.remoteIP()[0], client.remoteIP()[1], client.remoteIP()[2], client.remoteIP()[3]);
      PRINT("\nNew client @ ", szTxt);
#endif
      timeStart = millis();
      state = S_READ;
    }
    break;
  case S_READ: // get the first line of data
    PRINTS("\nS_READ");
    while (client.available())
    {
      char c = client.read();
      if ((c == '\r') || (c == '\n'))
      {
        szBuf[idxBuf] = '\0';
        client.flush();
        PRINT("\nRecv: ", szBuf);
        state = S_EXTRACT;
      }
      else
        szBuf[idxBuf++] = (char)c;
    }
    if (millis() - timeStart > 1000)
    {
      PRINTS("\nWait timeout");
      state = S_DISCONN;
    }
    break;
  case S_EXTRACT: // extract data
    PRINTS("\nS_EXTRACT");
    // Extract the string from the message if there is one
    newMessageAvailable = getText(szBuf, newMessage, MESG_SIZE);
    PRINT("\nNew Msg: ", newMessage);
    state = S_RESPONSE;
    break;
  case S_RESPONSE: // send the response to the client
    PRINTS("\nS_RESPONSE");
    // Return the response to the client (web page)
    client.print(WebResponse);
    client.print(WebPage);
    state = S_DISCONN;
    break;
  case S_DISCONN: // disconnect client
    PRINTS("\nS_DISCONN");
    client.flush();
    client.stop();
    state = S_IDLE;
    break;

  default:  state = S_IDLE;
  }
}
void scrollDataSink(uint8_t dev, MD_MAX72XX::transformType_t t, uint8_t col)
// Callback function for data that is being scrolled off the display
{
#if PRINT_CALLBACK
  Serial.print("\n cb ");
  Serial.print(dev);
  Serial.print(' ');
  Serial.print(t);
  Serial.print(' ');
  Serial.println(col);
#endif
}
uint8_t scrollDataSource(uint8_t dev, MD_MAX72XX::transformType_t t)
// Callback function for data that is required for scrolling into the display
{
  static enum { S_IDLE, S_NEXT_CHAR, S_SHOW_CHAR, S_SHOW_SPACE } state = S_IDLE;
  static char		*p;
  static uint16_t	curLen, showLen;
  static uint8_t	cBuf[8];
  uint8_t colData = 0;
  // finite state machine to control what we do on the callback
  switch (state)
  {
  case S_IDLE: // reset the message pointer and check for new message to load
    PRINTS("\nS_IDLE");
    p = curMessage;      // reset the pointer to start of message
    if (newMessageAvailable)  // there is a new message waiting
    {
      strcpy(curMessage, newMessage); // copy it in
      newMessageAvailable = false;
    }
    state = S_NEXT_CHAR;
    break;
  case S_NEXT_CHAR: // Load the next character from the font table
    PRINTS("\nS_NEXT_CHAR");
    if (*p == '\0')
      state = S_IDLE;
    else
    {
      showLen = mx.getChar(*p++, sizeof(cBuf) / sizeof(cBuf[0]), cBuf);
      curLen = 0;
      state = S_SHOW_CHAR;
    }
    break;
  case S_SHOW_CHAR:	// display the next part of the character
    PRINTS("\nS_SHOW_CHAR");
    colData = cBuf[curLen++];
    if (curLen < showLen)
      break;
    // set up the inter character spacing
    showLen = (*p != '\0' ? CHAR_SPACING : (MAX_DEVICES*COL_SIZE)/2);
    curLen = 0;
    state = S_SHOW_SPACE;
    // fall through
  case S_SHOW_SPACE:	// display inter-character spacing (blank column)
    PRINT("\nS_ICSPACE: ", curLen);
    PRINT("/", showLen);
    curLen++;
    if (curLen == showLen)
      state = S_NEXT_CHAR;
    break;
  default:
    state = S_IDLE;
  }
  return(colData);
}
void scrollText(void)
{
  static uint32_t	prevTime = 0;
  // Is it time to scroll the text?
  if (millis() - prevTime >= SCROLL_DELAY)
  {
    mx.transform(MD_MAX72XX::TSL);	// scroll along - the callback will load all the data
    prevTime = millis();			// starting point for next time
  }
}
void setup()
{
#if DEBUG
  Serial.begin(115200);
  PRINTS("\n[MD_MAX72XX WiFi Message Display]\nType a message for the scrolling display from your internet browser");
#endif
#if LED_HEARTBEAT
  pinMode(HB_LED, OUTPUT);
  digitalWrite(HB_LED, LOW);
#endif
  // Display initialisation
  mx.begin();
  mx.setShiftDataInCallback(scrollDataSource);
  mx.setShiftDataOutCallback(scrollDataSink);
  curMessage[0] = newMessage[0] = '\0';
  // Connect to and initialise WiFi network
  PRINT("\nConnecting to ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED)
  {
    PRINT("\n", err2Str(WiFi.status()));
    delay(500);
  }
  PRINTS("\nWiFi connected");
  // Start the server
  server.begin();
  PRINTS("\nServer started");
  // Set up first message as the IP address
  sprintf(curMessage, "%03d:%03d:%03d:%03d", WiFi.localIP()[0], WiFi.localIP()[1], WiFi.localIP()[2], WiFi.localIP()[3]);
  PRINT("\nAssigned IP ", curMessage);
}
void loop()
{
#if LED_HEARTBEAT
  static uint32_t timeLast = 0;
  if (millis() - timeLast >= HB_LED_TIME)
  {
    digitalWrite(HB_LED, digitalRead(HB_LED) == LOW ? HIGH : LOW);
    timeLast = millis();
  }
#endif
  handleWiFi();
  scrollText();
}

Downloads:

Video:

How to solve mirror image and orientation problems of matrix display if you are using old MD_MAX72xx library.

How to control RGB LED wirelessly using ESP8266 WiFi web interface

psadminetechpath — Tue, 21 Nov 2017 22:59:50 +0000

About:

In this project we are going to control 1 watt RGB full color LED diode using WiFi module ESP8266-01. You can use any WiFi enabled device to access web interface to control this RGB LED. Watch video at the bottom of this page.

Things you will need:

1W RGB LED
ESP-01 WiFi module
10Ω Resistance
ASM1117 3.3v (or any 3.3v voltage source)
USB to TTL converter (for programming esp-01)
Momentary push button (optional)
Android / Apple / Windows Phone or any WiFi enabled Laptop / Desktop (to control RGB LED)

Circuit Diagram for programming ESP-01 :

Steps :

1. Connect the circuit on breadboard as shown in above circuit diagram for programming ESP-01 WiFi module. You must use only 3.3v logic setting in TTL device.
2. In this tutorial we will used Arduino IDE to download code into ESP module. So, install Arduino IDE and add supporting board manager and ESP library into it. (Download links are given in download section)

Download and save source code on your computer and open it up using Arduino IDE.
Connect USB to TTL module to your computer.
Open Arduino IDE – Select board ‘Generic ESP8266 Module’ – Select Port of your TTL device (Here’s How to)
Open downloaded code.ino file into arduino and upload the code into ESP module by pressing upload button.
After uploading, Disconnect the ESP module from USB-TTL module and connect it to RGB LED as shown in bellow diagram.

Circuit Diagram for connecting RGB LED:

Steps:

1. Connect the final circuit as shown in above diagram and power it up using 5v battery or wall adapter.
2. ESP module will boot up and LED light will show fade effect in all three colors at startup.

Then open your device WiFi in discovery mode and you will see a new WiFi access point, named as RGB in discovery list.
Connect that WiFi access point, Open any web browser in that device and open ip address 192.168.1.1 , thats it, you will see a colorful RGB control screen to control your wireless RGB LED.

Note: Do not feed more than 3.3v to ESP-01 module

Source Code :

/* RGB web server with ESP8266-01 (ESP-01)
* There are only 2 GPIOs available in ESP-01: 0 and 2
* but RX and TX can also be used as: 3 and 1
* Wiring Circuit 
* 0=Red (GPIO0) D3
* 2=Green (GPIO2) D4
* 3=Blue (GPIO3) Rx
* www.etechpath.com
*/

#include 
#include 
#include 

const char *ssid = "RGB";
//Uncomment below line if you wish to set a password for ESP wifi network...
// const char *password = "87654321";  

const byte DNS_PORT = 53;
IPAddress apIP(192, 168, 1, 1);   //IP address of your ESP 
DNSServer dnsServer;
ESP8266WebServer webServer(80);

//Webpage html Code
String webpage = ""
"RGB control eTechPath.com"
""
""
""
"";
void handleRoot() 
{
// Serial.println("handle root..");
String red = webServer.arg(0); // read RGB arguments
String green = webServer.arg(1);  // read RGB arguments
String blue = webServer.arg(2);  // read RGB arguments

//for common anode
analogWrite(0, red.toInt());
analogWrite(2, green.toInt());
analogWrite(3, blue.toInt());
//for common cathode
//analogWrite(0,1023 - red.toInt());
//analogWrite(2,1023 - green.toInt());
//analogWrite(3,1023 - blue.toInt());
webServer.send(200, "text/html", webpage);
}
void setup() 
{
pinMode(0, OUTPUT);
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);

analogWrite(0, 1023);
analogWrite(2, 1023);
analogWrite(3, 1023);
delay(1000);
WiFi.mode(WIFI_AP);
WiFi.softAPConfig(apIP, apIP, IPAddress(255, 255, 255, 0));
WiFi.softAP(ssid);
dnsServer.start(DNS_PORT, "rgb", apIP);
webServer.on("/", handleRoot);
webServer.begin();
testRGB();
}
void loop() 
{
dnsServer.processNextRequest();
webServer.handleClient();
}
void testRGB() 
{ 
// fade in and out of Red, Green, Blue
analogWrite(0, 1023); // Red off
analogWrite(2, 1023); // Green off
analogWrite(3, 1023); // Blue off

fade(0); // Red fade effect
fade(2); // Green fade effect
fade(3); // Blue fade effect
}
void fade(int pin) 
{
for (int u = 0; u < 1024; u++) 
{
analogWrite(pin, 1023 - u);
delay(1);
}
for (int u = 0; u < 1024; u++) 
{
analogWrite(pin, u);
delay(1);
}
}

Downloads: