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16  Using Arduino / Displays / Re: lcd 20x4 problem on: April 11, 2014, 02:46:00 pm
The backlight has nothing to do with the LCD controller and hence the LiquidCrystal library or its associated code are irrelevant. 

Have you connected pins 15 and 16?


Don
17  Using Arduino / Displays / Re: LCD 20x4 to arduino uno on: April 11, 2014, 02:39:03 pm
You have a display that can operate over an extended temperature range.  Typically these devices need a negative voltage between LCD pin 3 and GND unless the ambient temperature is very high.

To check this out you can use a 9V battery.  Disconnect the end of the potentiometer that is currently going to GND and connect it to the negative side of the battery.  Connect the positive side of the battery to GND.  You should now be able to vary the voltage at LCD pin 3 from -9V to +5V.


Don
18  Using Arduino / Displays / Re: Problem with LCD? on: April 08, 2014, 09:56:43 am
Quote
But actually, one will suffice in general as the internal divider chain already totals 11k ...
Where have you been able to find information about the internal workings of the controller?  I have been looking for this.

Don

19  Using Arduino / Displays / Re: Can't get my LCD screen to work. Help? on: April 07, 2014, 09:55:27 pm
Quote
Is that possible? that I need to  connect other pins?
No.  But you do need to connect the required pins correctly.  Since your LCD module has a non-standard pinout you will not be able to just follow the pictures in most tutorials. 

I suggest that you disconnect everything and start over following this generic outline:


(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


20  Using Arduino / Displays / Re: Can't get my LCD screen to work. Help? on: April 07, 2014, 07:54:49 pm
Quote
...  but try connecting the second half of the control pins, like my hitachi has 8 control pins looks like you only have four. in some lcds the other four is the other half of the screen. good luck
If you believe this then I have a bridge you might be interested in purchasing.

Don
21  Using Arduino / Displays / Re: Problem with LCD? on: April 07, 2014, 06:37:16 pm
You might just as well connect LCD pin 3 to GND rather than use a resistor, but to provide the contrast voltage correctly you need a voltage divider, ie two resistors. 

A resistance near 1K ohms between GND and LCD pin 3 and about 10K ohms between +5V and LCD pin 3 will typically be a good starting point.


Don
22  Using Arduino / Displays / Re: [Solved] LCD03 i2c problem (only displays i2cmode@0xc6) on: April 07, 2014, 02:11:24 pm
Quote
Sorry if you feel that this topic is like pulling teeth. If I have misused the “posting instructions”; I’m sorry.
It's not that you misused anything, you just did not post enough information for anyone other than those who are already familiar with 'robot-electronics' part numbers to help you.

Don
23  Using Arduino / Displays / Re: LCD03 i2c problem (only displays i2cmode@0xc6) on: April 07, 2014, 11:11:52 am
This is like pulling teeth....  
Now identify the MD03 (or is it MD3)?

Have you looked at this --> http://forum.arduino.cc/index.php?topic=149018.0


Don
24  Using Arduino / Displays / Re: LCD03 i2c problem (only displays i2cmode@0xc6) on: April 07, 2014, 08:58:11 am
You might get some responses if you identified what an LCD03 is.

Don
25  Using Arduino / Displays / Re: Can't get my LCD screen to work. Help? on: April 06, 2014, 10:06:59 pm
It's possible that you damaged one or both of the LCD controllers when you had the improper wiring.  Try sending 80 characters to the display and see what happens.

Use this program as a guide:

Code:
#include <LiquidCrystal.h>

//LiquidCrystal lcd(rs,en,d4,d5,d6,d7);
  LiquidCrystal lcd(12, 11, 5, 4, 3, 2);       // put your pin numbers here

void setup()
  {
    lcd.begin(20, 4);                          // put your LCD parameters here
    for (char i=47; i<127; i++)                // send 80 consecutive displayable characters to the LCD
      {
        lcd.print(i);
        delay(100);                            // this delay allows you to observe the addressing sequence
      }
  }


void loop()
  { 
  }

Don
26  Using Arduino / Displays / Re: lcd display on: April 02, 2014, 09:41:53 pm
Yes.
Buy a replacement and get it working.   Then substitute your questionable one for the working one.


Don
27  Using Arduino / Displays / Re: LCD displays only blocks when I upload the Hello, World Example Code on: March 31, 2014, 10:07:52 pm
Quote
Is there another reason for the LCD  to display only blocks?
Basically this display usually results from a problem with the wiring and/or a problem with the program code.  You could, however, have a display that is horribly out of specification and in that case there could be a timing issue.

There is a library that was written to deal with 40x4 displays which have two HD44780 type controllers.  It will also handle normal single controller displays.  During the development of that library the author made an effort to adjust the time delays to accommodate the worst displays he could get his hands on so you might want to try it.

To get a copy start here:--> http://code.google.com/p/liquidcrystal440/ and follow the Downloads link to get to the latest version.


Don
28  Using Arduino / Displays / Re: LCD displays only blocks when I upload the Hello, World Example Code on: March 31, 2014, 04:21:50 pm
@LarryD
Why should he mess with code that works for everyone else?

Of course the tutorial code would be better for troubleshooting if it displayed static information on both lines in setup() and if loop() had no code.


@dannable
Quote
You have adjusted the potentiometer that controls the contrast?
He wouldn't see the blocks if the contrast wasn't set somewhere near where it should be.


@ckohen
Quote
Link to DataSheet:  http://www.microtivity.com/support 
Well the first two support answers do not relate to the LCD display and the diagram shows a voltage dropping diode where there should be a current limiting resistor.  Otherwise it is perfect.

Quote
Wired Exactly Like the example code says
I've heard that before.  We need to see a photograph of your connections to verify what you are saying.  Are you sure you didn't miss connecting LCD pin 5 to GND?

Don
29  Using Arduino / Displays / Re: LCD problem+video+code on: March 31, 2014, 08:21:47 am
Quote
Here the code, just before the function wich leads to the error is called:
Have you considered turning your phone 90 degrees when you take your videos?

You really should show all of the code.

You should also show an in-focus picture of your entire setup.

Right now we have no idea which Arduino pins you are using for your display.  For example if you are using pin 1 then the serial.print() can affect your LCD.


Don
30  Using Arduino / Displays / Re: LCD with Sensor Shield v5.0 on: March 30, 2014, 07:12:54 pm
Your LCD appears to have an I2C adapter.  This means that you cannot use the regular LiquidCrystal library that comes with the Arduino IDE.

Have you considered trying the example code on the Sainsmart web page?


Don
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