LCD Questions

I’m considering buying this (http://www.cutedigi.com/product_info.php?products_id=4192&osCsid=d6c99586c7b234133d683ebcab58348f) LCD for my arduino. As far as I can tell, it should work with the arduino fine (as it states, it uses the HD44780 Interface Chipset), but I have no idea how I would go about connecting it. I have searched but haven’t really been able to find anything. If anyone can shed some light as to which Pin is which (ie, enable, rs, d0, etc.), that would be great!

Thanks! :smiley:

EDIT: Hmmm, it seems that the page on CuteDigi does provide some information as to which pin goes where, but some explanation about what’s going on with the resistor (and “wiper”) it’s talking about would be nice…

After more research, I think I may have figured out some of it. The resistor it’s talking about is a potentiometer, whose ends are 5v and Ground, and the wiper goes to the v0 pin on the LCD? This is to adjust the contrast I believe. My new question is, what would happen if I just connected the V0 pin to ground, or simply to nothing at all? Would it default to highest contrast, lowest contrast, or simply not work? Thanks again :P.

ladyada has good info for how to hook HD44780 LCDs to an Arduino. Check this page.

And watch out, the tutorial and examples for using the LiquidCrystal library (here) don’t mention that you have to connect pins 15 & 16; they are necessary to power the backlight, if yours has one.

.andy

ladyada has good info for how to hook HD44780 LCDs to an Arduino. Check this page.

And watch out, the tutorial and examples for using the LiquidCrystal library (here) don’t mention that you have to connect pins 15 & 16; they are necessary to power the backlight, if yours has one.

.andy

Thanks! Still no idea about if what would happen if I just grounded the LCD’s pin 3 (Contrast Adjustment)?

You’d get whatever backlight contrast corresponds to 0 volts supplied to that pin.

You’d get whatever backlight contrast corresponds to 0 volts supplied to that pin.

Which is exactly my question :P. What contrast corresponds to 0 volts? Haha.

I don’t have mine hooked up now, but it think it was no contrast, that is, dark. Probably depends on the exact specs of your LCD.

You can also connect an output pin from the Arduino to that LCD pin and control the voltage/contrast from your program.

I don’t have mine hooked up now, but it think it was no contrast, that is, dark. Probably depends on the exact specs of your LCD.

You can also connect an output pin from the Arduino to that LCD pin and control the voltage/contrast from your program.

Indeed. With a PWM pin, I would suppose? Thanks for the help :).

yup.

Be careful with the schematics.
The new LiquidCrystal library included in Arduino 17 uses one less pin than before, I got into some trouble.
Look here to be sure to have the latest information: http://arduino.cc/en/Tutorial/LiquidCrystal :wink:

EDIT: In case you’re ok with buying from China/HK, you can get a 20x4 cheaper on eBay. I bought two different ones (yellow/black and white/blue), the quality is good.

In case you’re ok with buying from China/HK, you can get a 20x4 cheaper on eBay. I bought two different ones (yellow/black and white/blue), the quality is good.

Adafruit has a 16x2 backlit for $12 USD. Is that good?

Every LCD can do I think… I bought my last 20x4 10$ from eBay including shipping.

(I always order this kind of thing because I live in France, there is no much choice.)

Adafruit has a 16x2 backlit for $12 USD.  Is that good?It is a fine product, works as advertised, and she has good explanations of how to hook it up and program it on her site. And her shipping is fast and reasonable.

IMHO, it’s worth supporting people like that who select, sell, and support their stuff.

.andy

It is a fine product, works as advertised, and she has good explanations of how to hook it up and program it on her site. And her shipping is fast and reasonable.

IMHO, it’s worth supporting people like that who select, sell, and support their stuff.

.andy

Agreed. I also love to support American Sellers. Do you know if Adafruit is based here in the USA?

New York, New York

New York, New York

Cool, thanks everyone! :smiley: