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31  Using Arduino / Displays / Re: LCD Keypad Shield v2.0 only displaying on first left 8 caracters on: March 27, 2014, 04:53:25 pm
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Any idea what could be wrong ?
Have you looked through the other recent threads in this section of the forum?

Here are a few to check out:

http://forum.arduino.cc/index.php?topic=226853.0
http://forum.arduino.cc/index.php?topic=227598.0
http://forum.arduino.cc/index.php?topic=227289.0

Don




32  Using Arduino / Displays / Re: Help. LCD Stopped working when DC Motor is connected on: March 26, 2014, 09:49:06 pm
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Because the backlight of the LCD remains on even though the display goes blank.
The backlight is a completely separate system from the LCD.

Don
33  Using Arduino / Displays / Re: LCD display burns on: March 26, 2014, 04:01:01 pm
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These photographs show an LCD that is functioning correctly but is improperly initialized.
I guess that is a bit confusing.  I meant "these photographs show an LCD that is not defective but is improperly initialized".  The photograph in the original post showed a defective display.

Don
34  Using Arduino / Displays / Re: LiquidCrystal demo problem on: March 26, 2014, 12:07:33 pm
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However as soon as I connect the 10k potentiometer in order to adjust the contrast, the whole screen goes blank. Any ideas?!
The ends of the potentiometer go to pins 1 and 2, the center goes to pin 3.  You should be able to adjust the voltage at pin 3 from 0 to 5 volts.  The proper setting is typically around 0.5 volts.

If you connect pin 3 to GND you will typically have a bit too much contrast.  The characters will be very dark and the dots that are supposed to be blank will probably show a bit up thus making the characters less distinct.

You could try connecting a 1K resistor between pins 1 and 3 and a 10K resistor between pins 2 and 3.  You can use other nearby values as long as the ratio is about 1:10.


Don
35  Using Arduino / Displays / Re: LiquidCrystal demo problem on: March 26, 2014, 08:49:37 am
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Is there any progressive troubleshooting method I can use to identify the problem?

Here is my generic step by step approach that should work:

(1) If the module has a backlight then get it working properly.  This involves only pins 15 and 16 on most LCD modules.  Make sure to use a current limiting resistor if there is none on the LCD module.

(2) Get the power and contrast working properly.  This involves only pins 1, 2, and 3 on most LCD modules.  You should be able to just barely see blocks on one row of a two row display and on two rows of a four row display. 

NOTE:  The Arduino has not been used yet, except as a possible source for the power needed for the first two steps.  Do not try to go any further until this is working.  If you don't see the blocks then no amount of program code will help.

(3) Connect the LCD R/W pin (pin 5) to GND.

(4) Connect the six control and data wires between your LCD module and your Arduino.

(5) Upload your sketch and it should work.


Troubleshooting:

If you have a 16x1 display and there are blocks only on the left half of the row in step 2 then use lcd.begin(8, 2); in your sketch.

If you still don't get a display then make sure that your wiring matches the numbers in the descriptor (or vice versa).


Code:
//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);      // put your pin numbers here

If you get a display but it is garbled or has some other problems then try again with a 'static' sketch, one that displays a simple message on the top row of the display and then stops.  All of your code should be in setup() and loop() should be empty between the brackets.

Code:
#include <LiquidCrystal.h>

//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);      // put your pin numbers here

void setup()
  {
  lcd.begin(16, 2);                          // put your LCD parameters here
  lcd.print("hello, world!");
  lcd.setCursor(0,1);
  lcd.print("it works!");
  }

void loop()
  {
  }

If you are still having problems then we need to see a photograph of your setup that clearly and unambiguously shows all of the connections between your Arduino and your LCD module.  We also need a copy/paste version of the code that you are actually using, not a link to the code that you think you are using.

Don
36  Using Arduino / Displays / Re: LCD display burns on: March 26, 2014, 08:46:02 am
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Hi again, Andoni here with the same problem this time in another LCD
This is not the same problem as in the original post.

These photographs show an LCD that is functioning correctly but is improperly initialized.

This is a result of a problem with the connections with the programming or with both.  

Your contrast appears to be set properly.

Since all of your wires are the same color it is hard to do much troubleshooting of the connections using the photographs.  I don't see any connection to pin 5 of the LCD so please verify that this pin is connected to GND.  It also looks like you may be using the wrong data pins on your LCD.  You should be using LCD pins 11, 12, 13, and 14.

Are you sure that your constructor (LiquidCrystal lcd(RS, E, D4, D5, D6, D7);) matches your actual connections?


Don

37  Using Arduino / Displays / Re: Problem combining Servo library with LCD and Wire Library. on: March 25, 2014, 09:34:14 am
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After doing some trouble shooting, the problem doesn't occur until I specifically include the lcd.print("String") command for the lcd screen. Once I include that in my code, but servos become jittery when they should be stationary.

LCDs, especially those run via I2C, use lots of time delays.  Depending on how those delays are implemented in the library they very well could be having an influence on the operation of the servos.

Don
38  Using Arduino / Displays / Re: Problem with pin congurations on: March 25, 2014, 09:25:52 am
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... however, there is no indication of MISO or MOSi or DC or backlight pin.

Since that is a shield one would hope that they wired the board to match up with the corresponding pins on your Arduino.  After all that's the whole idea of using a shield.

One would also hope that you got some more information with your shield ....


Don
39  Using Arduino / Displays / Re: Problem with LCD Shield. on: March 25, 2014, 09:09:51 am
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What could be the problem? The compatibility with LiquidCrystal Library? I should use LCD 4-bit library? Or another thing?

We really need to know more about the specific device you have.  Is it really a 'shield' that plugs directly into your Arduino or is it a separate pc board that has to be connected with jumpers?

I think that is a 'Powertip' part number and as I recall some of them are use a non-standard pinout.

The LiquidCrystal library should work if you connect things correctly and set up the parameters correctly.

The LCD 4-bit library should be deleted from your computer so that you don't use it by mistake.  It is a poorly written library (read the comments if you want proof) that was cobbled together before the standard LiquidCrystal library was updated several years ago.


Don
40  Using Arduino / Displays / Re: Help about phi_panel using analog pins. on: March 25, 2014, 08:58:28 am
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Link is ok,  but from some strange reason last ")" is not notices as part of url.
That often happens to me when I use the editing buttons so maybe it's a feature of the forum software.

Go back and edit your post to put the last ")" before the "[/url]". 

It's always a good idea to preview your posts and check out the links before you actually submit them.


Don
41  Using Arduino / Displays / Re: Help about phi_panel using analog pins. on: March 24, 2014, 09:24:46 pm
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I appreciate any help since I new to arduino and phi_panel!
If that's a real phi-panel then you should be able to get help from the developer of the panel, liudr, here --> http://liudr.wordpress.com/gadget/phi-panel/.

Don

PS: You might want to fix your link.
42  Using Arduino / Displays / Re: Help. LCD Stopped working when DC Motor is connected on: March 24, 2014, 09:16:58 pm
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Any thoughts guys and gals?? This is a school project due in a week!
You could try searching this forum for other similar cases.  The same problem crops up with relays, solenoids, and anything else that's basically a coil of wire.

The search function provided with this forum software is slightly better than useless.  Try a Google search using this syntax:
--> search phrase site:arduino.cc


Don
43  Using Arduino / Networking, Protocols, and Devices / Re: Wireless connection between two Arduino's on: March 24, 2014, 06:49:48 pm
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So, if possible, please help!
If you search for Arduino mailbox notifier you might get a few hundred thousand ideas!

Don
44  Using Arduino / Displays / Re: scrollDisplayLeft() with Yellow IIC/I2C/TWI 1602 Serial Backlight LCD Display on: March 24, 2014, 02:37:59 pm
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Can someone please confirm that scrollDisplayLeft() is supported for LCD connected via I2C
That would depend upon the specific I2C library that you are using.

Most of them are based upon the regular LiquidCrystal library so they should perform in a similar manner.

Unfortunately the library usage of the term 'scroll' corresponds to the LCD controller term 'shift' which may not do exactly what you expect.  What actually happens is that entire display, all of the lines, are shifted simultaneously.


Don
45  Using Arduino / Displays / Re: from 16x2 to 16x4 frequency analyzer on: March 24, 2014, 12:59:59 pm
You should start out by changing   lcd.begin(16, 2);    to     lcd.begin(16, 4);    

Now, in a perfect world,  you should be able to set the cursor with lcd.setCursor(j, 2); or lcd.setCursor(j, 3); for the appropriate line.

Unfortunately the LiquidCrystal library does not deal with 16x4 displays correctly so without some changes to your code or to the library your output is going to be offset by four spaces.

Here are some previous threads dealing with the problem.
http://forum.arduino.cc/index.php?topic=14604.0      September 19, 2009
http://forum.arduino.cc/index.php?topic=46666.0      March 13, 2010
http://forum.arduino.cc/index.php?topic=63038.0      June 06, 2011
http://forum.arduino.cc/index.php?topic=70011.0      August 20, 2011
http://forum.arduino.cc/index.php?topic=93976.0      February 26, 2012
http://forum.arduino.cc/index.php?topic=190544.msg1408694#msg1408694       September 28, 2013

There is a thread with a very simple fix.  Look at reply #18
http://forum.arduino.cc/index.php?topic=63038.msg829540#msg829540   June 17, 2012


Don
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