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46  Using Arduino / Displays / Re: Help. LCD Stopped working when DC Motor is connected on: March 24, 2014, 09:16:58 pm
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

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

48  Using Arduino / Displays / Re: scrollDisplayLeft() with Yellow IIC/I2C/TWI 1602 Serial Backlight LCD Display on: March 24, 2014, 02:37:59 pm
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.

49  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.      September 19, 2009      March 13, 2010      June 06, 2011      August 20, 2011      February 26, 2012       September 28, 2013

There is a thread with a very simple fix.  Look at reply #18   June 17, 2012

50  Using Arduino / Displays / Re: DV-20208 on: March 24, 2014, 08:44:57 am
Why?  The pinout is provided on the link in his second post.

51  Using Arduino / Displays / Re: DV-20208 on: March 23, 2014, 08:24:53 pm
It looks like you should skip step 1 since:
   (1) your backlight requires more than 5 v to operate.
   (2) the seller recommends a 14 pin connection so apparently this LCD is visible without a backlight.

If you don't have a potentiometer for the contrast then try it with pin 3 connected to pin 1.  The display will be blank if you let pin 3 float.


52  Using Arduino / Displays / Re: Variables not showing on LCD screen on: March 23, 2014, 05:13:18 pm
Your LCD screen does not display your 'msg' the way that you expect.

Although it can display a total of 32 characters the messages do not wrap from the first line to the second the way you would think.

If you send 40 sequential characters to a 16x2 display the first 16 will be displayed on the top line and the next 24 will not be displayed at all.

For the reasons behind this unusual behavior follow the LCD Addressing link at

You will have to break your messages into two 16 character chunks and send the first to the first line and the second to the second line.

53  Using Arduino / Displays / Re: Using the LCM1602, What is the REAL Code for the Adruino Leonardo? on: March 23, 2014, 03:38:11 pm
Another related problem is that many vendors are now using terms such as "Arduino compatible" and "for Arduino" in their descriptions. 

This will eventually cause their web pages to show up in a search for Arduino and the phrasing is is not really incorrect since these devices will indeed work with the Arduino (and just about every other microcontroller as well).   

My feeling is that they are also counting on the fact that prospective purchasers will assume these terms as meaning that their devices will connect as easily as a 'shield' and maybe even work with the libraries provided with the Arduino IDE (Integrated Development Environment) which is typically not the case.

54  Using Arduino / Displays / Re: DV-20208 on: March 23, 2014, 02:52:04 pm
When I hook it all up to the "Hello World" sketch for testing purposes I'm not getting anything on the display what-so-ever.
If it is really HD44780 compatible then it should work if you connect it correctly.

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 but I think yours is different.  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 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.

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

//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.

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.

55  Using Arduino / Displays / Re: Help!! Unknown GLCD pinouts. Can not find datasheet on: March 23, 2014, 10:21:35 am
Even on the board the last two pins (17 and 18) where not even connected. So it uses only 16 pins including the backlight.
Are you sure that this isn't a multilayer board?

Connect power to pins 1 and 2 and measure the voltage between pins 1 and 18.  Hopefully you will find a negative voltage at pin 18 with respect to pin 1.

56  Using Arduino / Displays / Re: Using the LCM1602, What is the REAL Code for the Adruino Leonardo? on: March 21, 2014, 09:07:03 pm
Guys there is a lot of side comments and what appears to be arguing around yourselves
rather than helping Southview get his board going.
I'm sorry Bill but it does the beginners no good to let erroneous or misleading information get perpetuated.  

If you look at my responses to the OP you will see that they were correct and to the point.  I didn't introduce any extraneous or misleading information, all I did was correct the information that was added by raschemmel.

I did not respond to the last post by raschemmel because there is no way to logically refute such jibberish.


57  Using Arduino / Displays / Re: Using the LCM1602, What is the REAL Code for the Adruino Leonardo? on: March 21, 2014, 04:18:03 pm
... whereas with parallel lcds, the constructor does actually provide info the user needs to connect it.
No it doesn't.  It performs a similar function as it does for the I2C setup.  In this case the constructor tells the library how the pins on the LCD module relate to the pins on the Arduino.

The user must make sure that the actual hookup matches the constructor (or vice versa) but the purpose of the constructor is to give that information to the library.

58  Using Arduino / Displays / Re: Strange LiquidCrystal Error on: March 21, 2014, 04:13:15 pm
I guess you haven't been reading the other posts in this forum.  We have had two other situations just like yours this week.

59  Using Arduino / Displays / Re: LCD Display Random Characters 16x2 output variable data (data,DEC) on: March 21, 2014, 01:20:32 pm
Try getting rid of the lcd.clear().

After writing to the serial monitor try this:

  lcd.print("          ");

60  Using Arduino / Displays / Re: OPTREX DMC40457 don't work on: March 21, 2014, 10:53:19 am
My LCD has the "Samsung S6A0069X01" chip's and not the "HD44780".

The S6A0069 is an HD44780 compatible controller.  The X01 most likely refers to 'ROM version' which specifies the particular character set in the chip.

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