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Author Topic: LCD Screen Displaying Random Characters  (Read 495 times)
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Hello all, I just got an LCD screen yesterday and have been trying to use it. I got it to power up, however I can not get it to display things correctly. I tried uploading a simple "Hello World" program however nothing showed up. At one point I did get it to show up for a few seconds however right as I moved it the words disappeared. Also when I first start the program it shows nothing on the screen but if I start moving it around a little bit it starts displaying random characters. Any suggestions?


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Loose connection. Check all your wires.
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~Tom~

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We've seen the display, now can you turn on the light so we can see your wiring and the solder connections on the pins ?
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Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,
DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

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Here are some more pictures. I have tried re-connecting everything on the other side of the breadboard but I still got the same results. I was thinking it might be a bad breadboard however I was using it for other things last week and it worked fine.


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Picture 2


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I'm afraid that I have to say that the soldering of the pin headers is not very good. There are several pins which look like they could be cold solder joints which would explain the intermittent problems.

You need to use a little more solder on some of the joints, and on all of them leave the soldering iron on the joint for longer - maybe ~5 or so seconds of heat on each join after you have applied the solder to give it time to flow onto the pads.
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ditto that. If you can get some flux that works wonders. If I were you, I would get some solder wick and start over. Wick off the solder. Put some flux on and resolder it correctly. We really don't have enough info to say conclusively that there is anything wrong with the hardware (other that it doesn't look great) because you have not uploaded your code. Since you did not cite a compile error we can rule that out, but the first parallel lcd I had (16x2) did not work with the arduino hello world code and when I downloaded the example code at Hobbycomponents it worked. (see attached) How is that possible ?
Is this what you used to wire it up ?
http://arduino.cc/en/Tutorial/LiquidCrystal#.Uyo5nvldW_g That is what everyone is assuming right now since you didn't ask how to wire it up.

* HOBBYCOMPLCD_4bit_lcd.ino (1.73 KB - downloaded 8 times.)
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Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,
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I wired it exactly like this website:
http://learn.adafruit.com/character-lcds/wiring-a-character-lcd
I attached the program I am trying to use to run it, however I do not thing the code is the problem because at one point it actually did say "hello world" for a few seconds until I tried touching it and then it went away. I think I just might trying to re-solder it this weekend as you suggested.

* HelloWorld.ino (0.64 KB - downloaded 7 times.)
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Quote
I wired it exactly like this website:

"It's like déjà vu all over again." (Yogi Berra)

Don
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