Can't Figure Out I2C LCD?

Using Arduino Displays
1

I just bought a couple of cheap LCD's off of ebay, but now I can't figure out how the heck to get them working. I thought it was easy but I didn't look into it before buying them... How would I get these things working?

http://www.ebay.com/itm/IIC-I2C-Serial-LCD-2004-Module-Display-f-Arduino-Works-w-Official-Arduino-Board-/321355060928?ssPageName=ADME:L:OU:US:1120

2

Maybe this will help you:
http://arduino-info.wikispaces.com/LCD-Blue-I2C

You get what you pay for :wink:

3

LarryD:
Maybe this will help you:
http://arduino-info.wikispaces.com/LCD-Blue-I2C

You get what you pay for :wink:

Thank you! I swear I've been googling for hours and couldn't get anything to work. That tutorial worked PERFECT! Thanks a million!

4

Okay, this isn't related to my LCD but it's the same project, and it seems spammey to post another thread just for this. So I'm trying to make a water meter, but I don't know how to divide and include decimals. In the code below, I would like the integer "gallons" to go out to at least 2 decimals.

Ignore the // sidenotes on the code, I recycled some code from a previous project.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

int sensor = 12;      //Flow meter is attached to pin 12

int count;            //Variable for storing the current tick count
int pcount;           //Variable for storing the previous tick count
int sstate;           //Variable for storing the current state of the coin sensor
int psstate;          //Variable for storing the previous state of the coin sensor
int gallon;

LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  // Set the LCD I2C address


void setup(){
  Serial.begin(9600);
  
  lcd.begin(20,4);                       // initialize the lcd for 20 chars 4 lines and turn on backlight

  lcd.backlight();                       // finish with backlight on  

  lcd.setCursor(1,0);
  lcd.print("Gallons Dispensed:");
  
  pinMode(sensor, INPUT);      //Sensor pin is an input
  
  count = 0;                   //Sets the current coin count to 0
  pcount = 0;                  //Sets the previous coin count to 0
  sstate = 0;
  psstate = 0;
  gallon = 0;
}


void loop(){
  sstate = digitalRead(sensor);
  
  if(sstate == 1 && psstate == 0){
    count = pcount + 1;
  }
  
  gallon = (count/1249.19);
  lcd.setCursor(1,2);
  lcd.print(gallon);  
  
  Serial.print(count);
  Serial.print(", ");
  Serial.println(gallon);
  
  pcount = count;
  psstate = sstate;
  delay(5);
}
5

gallon = (count/1249.19);

You have int gallon;
Make it float gallon;

http://arduino.cc/en/Reference/Float

6

LarryD:
gallon = (count/1249.19);

You have int gallon;
Make it float gallon;

http://arduino.cc/en/Reference/Float

Thanks again! And this isn't necessary right now, but if I wanted more (or less) numbers after the decimal, how would I do that?

Just kidding, figured it out. Just add a comma and the # of decimals I want after the "print (gallon)". So "print (gallon, 5)"

7