Hey everyone,
this is my first post so im sorry if i didnt post it on the correct forum section.
Anyway, I have recently bought an arduino UNO board, And a LCD2004 Sainsmart display. I was looking for tutorials to wire the LCD to the arduino, But i all i found where diagrams with other boards that i didnt know if they followed the same wiring as the Arduino ONE. If someone could please help me by giving me a diagram or some instructions, It would be greatly appreciated
Thanks
Hablas espanol , no ?
Porque los gringos no saben que UNO es ONE ! (Talves algunas..).
Ok, can you post a link to where you bought the lcd or a photo of it ?
Also, you need to specify if it is the standard 4-bit parallel with 16 pins or if it is an I2C with a "backpack" module
having a four pin connection (Vcc, gnd, SDA,SCL)
When we have that info we can go from there....
Take a look at this post.
http://forum.arduino.cc/index.php?topic=212470.new;topicseen#new
Then read this:
http://arduino-info.wikispaces.com/LCD-Blue-I2C
STEP 1:
FIND OUT THE ADDRESS of your display.
You can download the Guesser program yourself here:(Reply #11)
http://forum.arduino.cc//index.php?topic=157817.msg1235230#msg1235230
You will notice that the issue in the first link I gave above was that he did not have the
correct address in his descriptor.
I guess I can't assume you know how to connect it
SDA goes to arduino pin "A4"
SCL goes to arduino pin "A5".
You need the I2C library installed :
look here:
https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads
Gracias por la respuesta, Si hablo espaniol.
I bought it from here> http://www.amazon.com/SainSmart-Serial-Module-Shield-Arduino/dp/B0080DYTZQ/ref=sr_1_1?ie=UTF8&qid=1390424923&sr=8-1&keywords=LCD2004
it seems that it is the backpack module you mentioned since it has a GND pin, VCC pin, SDA pin and SCL pin.
Thanks in advance
Thanks for the reply.
Im assuming that for the LCD screen wiring, Those are the cables that are needed excluding the ones that supply power, Right?
And for the zip file you attached, (im a noob, jijiji) How am i supposed to run it. (im using a macbook if thats important, However i have a windows PC too that i could use)
Thanks
EDIT> I already figured out how to open PDE files, silly me 
so you're good ? (estas bien ?)
Truth is, I have not done so much.
- What am i supposed to do with the PDE file? I have already opened it, But should i upload it to my Arduino ONE board? (I still have not wired the LCD screen to my board)
- From what you posted in here, I read> SDA goes to arduino pin "A4", SCL goes to arduino pin "A5". What i want to ask is that, Are those the only pins i have to connect, i mean, just those two?
Thanks for helping me along, Im just very new to this (jijij)
For now, I'll walk you through it but later when you have time you really should research I2C protocol.
First of all , forget that you know that "UNO" means "ONE" . Just get in the habit of referring to it an "UNO",
because otherwise you are just going to confuse someone else later on.
I2C is a communication protocol that allows multiple devices to run on the same 'bus'. If you are familiar
with the old PC Motherboards with slots for PCI cards (or other types), that is a 'bus', where everything is
connected on all of them with some exceptions. So you can have ten (or more of course) different lcds or anything else
all connected together with 4 wires This protocol is classified TWI (TWO WIRE INTERFACE) because
you don't count the +5V Vcc or GROUND connections. That is assumed. So yes, just those two wires PLUS Vcc & GROUND.
Next, there are two other things you need to get correct for it to work. You need have the correct
address of the device. You can find that out using a SCANNER, which you can copy from here:
http://playground.arduino.cc/Main/I2cScanner
and paste into a blank IDE screen. You do have the IDE installed correct ? What version ?
Connect the three wires. Just to be safe add 4.7k pullup resistors (one each) from A4 & A5 to +5V. I'll explain that later.
The other thing you need is the correct library. Unfortunately not all I2C lcds run on the same library.
I have two that use different libraries so if I need to change from one to the other I have to remove the
old library and save it somewhere until I need it and install the new library. The scanner program only
needs the Wire library which is included in the IDE installation so it should work and print the found
address to the serial port which you can see using the serial monitor. Once you have the address then
you need to put that into the lcd descriptor (or constructor) (between the dashed lines)
//DFRobot.com
//Compatible with the Arduino IDE 1.0
//Library version:1.1
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
//=====================================
LiquidCrystal_I2C lcd(0x27,16,2); <= DESCRIPTOR // set the LCD address to 0x27 for a 16 chars and 2 line display
//=====================================
void setup()
{
lcd.init(); // initialize the lcd
// Print a message to the LCD.
lcd.backlight();
lcd.print("Hello, world!");
}
void loop()
{
}
The address is in Hexadecimal so it is 0x27.
If the scanner returns any other value then that is the value you use to REPLACE the current address 0x27.
Then you make sure you have one of the I2C libraries installed and try it.
Find out where you "sketch" folder is by doing a "File\Preferences " in the IDE .
The try "File\Examples\LiquidCrystal_I2C\hello_world_I2C"
I'm not at home right now so I am can't look at it so I am just guessing on the spelling above.
What you are looking for is LiquidCrystal, under "File\Examples...."
Under LiquidCrystal there will a folder called "Examples" that should contain an example named
something like "Hello World I2C" or "LiquidCrystal_I2C\hello world".
Load that program and replace the address with the one from the scanner and see it displays "hello world"
If not then you probably need to try a different library.
Since you don't have a lot of experience you need take screenshots so I can see what you have
installed.
Do a "File\Examples ..." and take a screenshot of the menu that pops up of installed libraries.
Do you use a Windows or Mac ?
I hope it's windows because if not I won't be able to open the screenshot.
I need to know if the library on the pop up menu says "LiquidCrystal" AND "LiquidCrystal_I2C" or JUST
"LiquidCrystal" ? And also if the Examples under that tab have one called "hello world" AND "hello world_I2C"
or if both examples are listed under a single tab called "LiquidCrystal".
Good luck.
Let me know how it goes...
Thanks for the reply!
Ill try to set it all up tomorrow and report back
raschemmel - that was a great explanation that you gave to newbie santiagoar. Its really good to see people taking the time to give clear concise directions 
I am sending a karma point your way
Gracias Pedro !
Necessito todo la Karma que puedo agarar porque avezes le moleste alguna gente XD
Thanks Pedro,
I can use all the help I can get. I've stepped on a few toes here and there and ruffled some feathers but I'm learning.
When I started in electronics ("back in the day....") I had to learn it completely on my own with Heathkit homestudy
courses. (that sort of dates me huh ?).