I am working on an alarm/weather station project and I wanted to use an LCD but dint want to have a lot of wires so I order a controller. This is just a very basic tutorial on how to hook it up, for the beginners like my self.

Step 1: Parts

Parts list:

1. LCD in this case a 16x02

1. I2C 1602 LCD Controller ($1.99 on ebay free shipping)

4. Jumper wires

1. Arduino ( I have a mega)

Step 2: Soldering

Now we solder the LCD and the controller. make sure you have the correct pin arrangement. Mine doesn't have a mark for pin one, but I just looked at the 5+ and GND inputs to figure it out.

Step 3: Connecting

it is very simple to connect only 4 wire 5+ and GND and SDA goes to Arduino pin 20 and SCL to pin 21 on my arduino mega. depending on what you have it might be different.

Step 4: The Code

Since the seller doesn't provide any info I neede to find the address for the module so I ran an I2C scanner
//Written by Nick Gammon
// Date: 20th April 2011

#include <Wire.h>

void setup() {
Serial.begin (115200);

// Leonardo: wait for serial port to connect
while (!Serial)
    {
    }

Serial.println ();
Serial.println ("I2C scanner. Scanning ...");
byte count = 0;

Wire.begin();
for (byte i = 1; i < 120; i++)
{
    Wire.beginTransmission (i);
    if (Wire.endTransmission () == 0)
      {
      Serial.print ("Found address: ");
      Serial.print (i, DEC);
      Serial.print (" (0x");
      Serial.print (i, HEX);
      Serial.println (")");
      count++;
      delay (1); // maybe unneeded?
      } // end of good response
} // end of for loop
Serial.println ("Done.");
Serial.print ("Found ");
Serial.print (count, DEC);
Serial.println (" device(s).");
} // end of setup

void loop() {}

Step 5: The Code Part II

the code is very simple..................................but you are going to need F Malpartida's LCD LIB https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads Once again very basic very simple.
#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h> // F Malpartida's NewLiquidCrystal library

#define I2C_ADDR 0x20 // Define I2C Address for controller
#define BACKLIGHT_PIN 7
#define En_pin 4
#define Rw_pin 5
#define Rs_pin 6
#define D4_pin 0
#define D5_pin 1
#define D6_pin 2
#define D7_pin 3

#define LED_OFF 0
#define LED_ON 1
LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);

void setup()
{
lcd.begin (16,2); // initialize the lcd
// Switch on the backlight
lcd.setBacklightPin(BACKLIGHT_PIN,NEGATIVE);
lcd.setBacklight(LED_ON);
}

void loop()
{

// Reset the display
lcd.clear();
delay(1000);
lcd.home();

// Print on the LCD
lcd.backlight();
lcd.setCursor(0,0);
lcd.print("Hello, world!");
delay(8000);
}