Arduino Compatible IIC / I2C Serial 2.5″ LCD 1602 Display Module

This is a quick description of how to hook up the LCD module to an Arduino. FastTech currently offers the unit for $5.83 (free shipping).

LCD1602Display_I2C-Front LCD1602Display_I2C-Back

In order to have some ‘meaningful’ values to show on the LCD display the setup includes a potentiometer (any value between 5k and 50k should work) to create analog input values:


#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>
For details about the LCD display with I2C support see
The reviewer comments by docpayce and particularly JackWP associated with the two product pages above have been very useful.

Connect the LCD: VCC -> 5V, GND -> GND, SDA -> A4 (PortC4, ADC4), SCL -> A5 (PortC5, SDA)

The LiquidCrystal_I2C library needs to be downloaded and installed from here:

#define I2C_ADDR 0x27
#define En_pin 2
#define Rw_pin 1
#define Rs_pin 0
#define D4_pin 4
#define D5_pin 5
#define D6_pin 6
#define D7_pin 7

LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin,BACKLIGHT_PIN,POSITIVE);
LCD *myLCD = &lcd;

int SENSOR_PIN = 0; // center pin of the potentiometer

void setup()
  lcd.begin(16,2);               // initialize the lcd
  lcd.home ();                   // go home
  lcd.print("Hello, ARDUINO ");

void loop()
  int sensorValue = analogRead(SENSOR_PIN);
  // set cursor to second row, first column
  lcd.setCursor(0, 1);
  lcd.print("      ");
  delay (100);

Kudos to docpayce and particularly JackWP for pointing to, and figuring out the constructor parameters (see URL references at the top of the Arduino sketch).

6 thoughts on “Arduino Compatible IIC / I2C Serial 2.5″ LCD 1602 Display Module”

  1. Dr. Rainer Hessmer

    I have a problem with the code on line 30 and 31.
    The given errors are :
    error: ‘POSITIVE’ was not declared in this scope
    error: expected constructor, destructor, or type conversion before ‘*’ token
    Can you help me pleas?

    1. Hi Jan, I’m having the same problem; if you’ve gotten the answer, then can you help me too.

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