Geeetech LCD Keypad Shield v2.0 Problems Displaying

Other Hardware Displays
1

Hello everyone,

I've tried looking through the forums for similar issues, but all of the solutions found in other forum posts don't seem to work for me.

A friend recently got me the GE Tech LCD Keypad Shield v2.0 for Christmas (http://www.geeetech.com/wiki/index.php/Arduino_1602_LCD_KeyPad_Shield)

I currently have an Arduino Uno. I've attached the Shield to the Uno like so:

Imgur

Imgur

When I plug in the power, everything turns on and the first line has all squares:

Imgur

Backlight works as well:

Imgur

However, if I try to upload any code using the LiquidCrystal library, the screen goes blank and nothing ever happens, like so:

Imgur

Imgur

I've tried running a couple pieces of code, the first is the HelloWorld code example with the pins in the LiquidCrystal initialization switched to match the documentation:

#include <LiquidCrystal.h>

// This line is changed from the example to match the documentation
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

void setup() {
  lcd.begin(16, 2);
  lcd.print("hello, world!");
}

void loop() {
  lcd.setCursor(0, 1);
  lcd.print(millis()/1000);
}

I've also tried running the code example on the shields documentation http://www.geeetech.com/wiki/index.php/Arduino_1602_LCD_KeyPad_Shield

I've tried uploading the code from a Mac (through the /dev/tty.usbmodem1451 port) as well as through a Windows PC (through the COM3 port).

I'm using the Arduino 1.0.6 IDE

I'm at a loss for how to debug this further. Any help would be greatly appreciated.

Thanks!

2

When you turn the contrast pot from one end to the other, does the row of black squares change to something else. It's unclear from the documentation if the letters are supposed to be dark or light, perhaps a different contrast setting will bring them out.

3

Thanks for responding.

When I turn the contrast pot without any LiquidCrystal code uploaded, the line of Black Squares fades in and out, but with the code running, changing the contrast does nothing - still has nothing showing up.

4

I would use a multimeter to try and determine if there is continuity from the pins/pads which are along the edge of the shield to the underlying pins on the UNO when the LCD shield is plugged into the UNO. Evidently, power, ground and the backlight control pin 10 are conneted. Power should be off when you do this.

There is a little sliver of trace coming out from the sides of the female pin headers on the UNO which you should be able to get a probe on. Pay particular attention to the pins selected in your constructor, as well as the RW pin. which should be tied to ground. There should not be more than a few ohms top to bottom. Can you verify this?

If you have continuity on all the pins going to the UNO underneath, then its time to check the continuity on the shield from those pins to the pins on the LCD.