ESP8266 and 16x4 Character LCD Example

Overview

Using a character display with a micro-controller is simple for most of students in embedded programming. A parallel port HD44780 based character LCD is popular among students, electronic hobbyists, and engineers. This 8-bit parallel port interface LCD commonly uses its 4-bit data transfer mode to save the number of I/O, and reducing complexity in wiring. However in programming section, the use have to send data or command twice. That's not a problem in programming.

 

The HD44780 base character LCD are widely used and available at very low cost, around 1USD. It has different color, dimensions and display sizes. There are a lot of replacement display controllers for this conventional chip. They are very low cost and lower power consumption. 

ESP8266 NodeMCU Programming and Interfacing with a 16x4 LCD

Using Arduino IDE to to program and interface with any modules is common today since it has a lot of libraries and community supports. Arduino modules are available at very low cost and very easy to test. Similarly, we don't need to do manual C/C++ coding for a 16x4 LCD module. There are a lot of reliable, free and easy to use libraries of this stuff.

Arduino LiquidCrystal Library

The Liquid Crystal is compatible with ESP8266 MCU.

 

LiquidCrystal HelloWorld Example

 

I use the LiquidCrystal library installed in my Arduino IDE. To test it, open one example - for instance the HelloWorld.ino . 

I opened and modified this example to work with my old 16x4 character LCD. 

NodeMCU Arduino Source Code 

// include the library code:
#include <LiquidCrystal.h>

// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = 16, en = 5, d4 = 4, d5 = 0, d6 = 2, d7 = 14;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 4);
  // Print a message to the LCD.
  lcd.print("hello, world!");
  lcd.setCursor(0, 1);
  lcd.print("ESP8266 NodeMCU");
  lcd.setCursor(0, 2);
  lcd.print("LCD Programming");
  lcd.setCursor(0, 3);
  lcd.print("Using Arduino");
  delay(5000);
  lcd.clear();
  lcd.print("ESP8266 Running:");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis() / 1000);
  lcd.setCursor(0,2);
  lcd.print("Seconds");
  delay(500);
}

Schematic 

I draw this circuit using easyEDA. 

Schematic

Testing using Arduino Module

I tested it using my DIY NodeMCU TWI board. 

My DIY NodeMCU TWI board

My DIY NodeMCU TWI board

 

 

WiFi Connection Information

Here I use the ESP8266 WiFi feature to show connection status to home Wi-Fi router. It will show the IP address assigned by the router after a succeed wireless connection. 

Arduino Source Code

// include the library code:
#include <LiquidCrystal.h>
#include <ESP8266WiFi.h>

const char* ssid = "your-ssid";
const char* password = "your-password";
// Create an instance of the server
// specify the port to listen on as an argument
WiFiServer server(80);

// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = 16, en = 5, d4 = 4, d5 = 0, d6 = 2, d7 = 14;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 4);
  // Print a message to the LCD.
  lcd.print("ESP8266 nodeMCU");
  lcd.setCursor(0, 1);
  lcd.print("LiquidCrystal");
  lcd.setCursor(0, 2);
  lcd.print("LCD Example");
  lcd.setCursor(0, 3);
  lcd.print("and WiFi Info");
  delay(5000);
  Serial.begin(115200);
  
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Connecting to");
  lcd.setCursor(0,1);
  lcd.print("Home Router");
  // Connect to WiFi network
  Serial.println();
  Serial.println();
  
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(F("."));
  }
  Serial.println();
  Serial.println(F("WiFi connected"));

  // Start the server
  server.begin();
  Serial.println(F("Server started"));

  // Print the IP address
  Serial.println(WiFi.localIP());
  delay(5000);
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Connected IP");
  lcd.setCursor(0,1);
  lcd.print(WiFi.localIP());
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 2);
  // print the number of seconds since reset:
  lcd.print(millis() / 1000);
  lcd.setCursor(0,3);
  lcd.print("Seconds");
  delay(500);
}

Pictures

I tested it using my DIY NodeMCU TWI board. 

 

My DIY NodeMCU TWI board

my DIY NodeMCU TWI board

My DIY NodeMCU TWI board