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Did you do this step:
Open up the File?Examples?LiquidCrystal?HelloWorld example sketch
Now we'll need to update the pins. Look for this line:
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
And change it to:LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
To match the pin table we just made.Now you can compile and upload the sketch
I followed all the instructions perfectly.
I've heard that before....
...or must I buy a new LCD?
It's probably OK. Did you follow this step?
Next we'll connect up the backlight for the LCD. Connect pin 16 to ground and pin 15 to +5V through a series resistor. To calculate the value of the series resistor, look up the maximum backlight current and the typical backlight voltage drop from the data sheet. Subtract the voltage drop from 5 volts, then divide by the maximum current, then round up to the next standard resistor value. For example, if the backlight voltage drop is 3.5v typical and the rated current is 16mA, then the resistor should be (5 - 3.5)/0.016 = 93.75 ohms, or 100 ohms when rounded up to a standard value. If you can't find the data sheet, then it should be safe to use a 220 ohm resistor, although a value this high may make the backlight rather dim.
The resistor goes in place of the red wire shown between LCD pin 15 and +5V.
I assume you know that the photograph is upside down.
Don
while trying to get mine to work, I came upon a similar error. Mine looked exactly the same as in the image. My problem ended up being my poor soldering of the pin headers, and so I redid it and fixed it. $10 seems like a lot to me. If you are willing to wait a few weeks for shipping you can get really good ones on ebay for about $3 (that's what I did).
seb
$10 seems like a lot to me. If you are willing to wait a few weeks for shipping you can get really good ones on ebay for about $3 (that's what I did).
The $3 devices sold on eBay are likely to be manufacturer's rejects that are out of tolerance in one way or another. They will probably be suitable for many hobby applications but you may have to tinker with the software (typically the time delays) to get some of them to work reliably. I would buy one myself but you do have to be aware of the possible problems.
Don
Your problem is quite common and almost never results from a defective LCD module. If resoldering the pins doesn't fix the problem then you will have to give us some more information to work with. We will need a photograph that clearly shows all of the connections between your Arduino and your LCD module. We will also need a copy/paste version of the actual sketch that you are using, not a reference or link to the sketch that you are attempting to use.
Don
(Dr. Liu must be on vacation otherwise he would have already asked for this information.)
This might be the old "stick a diode on the reset pin" issue. Try moving any of connections away from the 4 & 7 pins on the arduino.
Most likely the lcd panel has it's pins pulled up and that causes an issue with the pre- R3 UNO's on their 4 & 7 pins. The new R3 uno has a diode on its reset pin to correct this from happening.
Add a blinking routine to see if the uno is really running. You can also just try resetting the uno with power still applied.