LCD Screen Help

I'm starting to experiment with an LCD screen. I just tried the Hello world project, but I came across a problem. My 2x16 LCD displays rectangles over the first line (picture below). Instead of hooking it up to a potentiometer, I put the LCD pin labeled "Vo" in the "GND" port on the arduino. The LCD screen is a 3.3 volt, so I have it plugged into 3.3V on the arduino.

Picture:

Thanks! -duemilanove

I think you’ve solved your own problem. Use a potentiometer.

Yeah, I'll try that.

The LCD screen is a 3.3 volt, so I have it plugged into 3.3V on the arduino.

Well if it is completely 3.3v then using 5v data from the arduino might do it damage.

Mowcius

Looking at the picture yes a pot will help but the darlk bars at the top surgest the lcd is not initialised, don’t forget to ammend this line for your own connections

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

I have had the same problem, then I found out that I have to connect the LCD's pin5 R/W to Ground(0V)

Thanks! :slight_smile:
-My LCD is hooked up to 3.3volt so I think that should be fine.
-I’ll add a potentiometer and check the code.
-The R/W pin is connected to Ground.

-My LCD is hooked up to 3.3volt so I think that should be fine.

Ok, so it is supplied 3.3V…
But the signals the arduino sends out will still be 5V, which can cause damage to the display as mowcius stated.

Ok, so it is supplied 3.3V…
But the signals the arduino sends out will still be 5V, which can cause damage to the display as mowcius stated.

So can I use a resistor to control this? If so what kind of resister? At the moment I have some 330 ohm’s and 10K’s, but I could find some others somewhere if I needed too.

EDIT: If you want to, here is a link to check out the specs of LCD Screen I have: http://www.sparkfun.com/commerce/product_info.php?products_id=9053

So can I use a resistor to control this? If so what kind of resister?

well you would need to make some voltage dividers with those resistors for this... putting a resistor directly might not work.

well you would need to make some voltage dividers with those resistors for this... putting a resistor directly might not work.

Thanks. Does know of a schematic or diagram showing how to hook this up?

The Hello World page has diagrams for hooking up the LCD.

http://arduino.cc/en/Tutorial/LiquidCrystal

@ digimike: Yeah, I know that :) Thanks anyway

I want to know how to hook up resistors to change the 5V coming out of the arduino to 3.3V to power and send data to my 3.3V LCD. Does know of a schematic or diagram showing how to hook this up?

Using a series resistor (1K to 10K) will limit the current driven into the LCD's I/O pins, or you can use this schematic. I am useing the 1K resistors in series.

Thanks for all your help! I’m really a beginner at using the arduino, so I might do some easier projects before I jump into LCD’s. I will definitely keep this for future reference though. :slight_smile: If there is anything else I need to know about LCD’s or connecting a 3.3volt LCD to 5volts, please leave a reply!

-duemilanove
Thanks again! :sunglasses:

so I might do some easier projects before I jump into LCD’s.

Any easy project can be made difficult by choosing components that don’t match (such as a 3.3v LCD and a 5v Arduino).

You can make your LCD project easier in one simple step - get a 5 volt LCD module (almost any one except the one you have).

Don

The schematic that you see is for two-way communication, when data flows from 5V I/O to 3.3V I/O and 3.3V I/O to 5V I/O, but in your case (Arduino to 3.3V LCD) data runs only from Arduino to LCD module, that's why I recommend that you try to use series resistors (1K to 10K) at the 4 data lines from Arduino to LCD module. I have tried this method, it is easy and safe.

... that's why I recommend that you try to use series resistors (1K to 10K) at the 4 data lines from Arduino to LCD module.

Don't forget the other two lines, RS and E.

Don

@floresta
Yes ofcourse, RS and E too, thank you for reminding.

Any easy project can be made difficult by choosing components that don't match

Yes, I figured that out very quickly after people told me that 5V will damage a 3.3V display. I don't think it is damaged though. Well that's how it goes when you buy something that has so many different features that you just buy the cheapest one. :-/

Thanks again everyone, I do plan to work with LCD's sometime :)