Show Posts
Pages: 1 2 3 [4] 5 6 ... 287
46  Using Arduino / Displays / Re: LCD current draw on: July 24, 2014, 07:46:27 pm
Quote
So even if i posted a back picture it wouldn't help to identify what model it is
You never know.  Someone might recognize it.

Quote
Too less current? What is the current and voltage applied through a multimeter when looking for continuity or short circuits?
I'm not sure about digital multimeters but for the old analog meters the voltage and current depended upon which resistance range you were using.  Some meters even had different batteries for the higher and lower ranges.

I remember how some of my students would try to use an ohmmeter to test the fuses that were used to protect the laboratory microammeters.  Every one of the fuses that they tested, even the new ones right out of the box, tested bad.


Don
47  Using Arduino / Displays / Re: Displaying time on a 4x20 LCD on: July 24, 2014, 07:40:23 pm
Print leading zero

Code:
   
   if(second <10)
  {
    lcd.print("0");
  }
  lcd.println(second);
   

The lcd.println(...); is going to introduce extraneous characters.  Surely you meant lcd.print(...);

Don
48  Using Arduino / Displays / Re: Displaying time on a 4x20 LCD on: July 24, 2014, 07:38:09 pm
Quote
... so if this has been answered, could someone point me in the right direction, I did have a 'Google' before trying here but had no joy.
This problem comes up quite regularly but coming up with the correct search terminology is not easy.

Here is one of the latest threads : --> http://forum.arduino.cc/index.php?topic=255213.msg1805883#msg1805883
And another: --> http://forum.arduino.cc/index.php?topic=254767.msg1802652#msg1802652
yet another: --> http://forum.arduino.cc/index.php?topic=118704.5


Don
49  Using Arduino / Displays / Re: LCD current draw on: July 24, 2014, 07:22:04 pm
Quote
Unfortunately i've mounted the LCD and it's really difficult to take a back picture.
It would have been prudent for you to have taken pictures before mounting the device. 

I do this routinely for most of what I buy now.  It's a lot easier to get the model number for a washing machine I bought 6 years ago by looking at my computer rather than by crawling around on the floor with a flashlight and magnifying glass.


Don
50  Using Arduino / Displays / Re: LCD current draw on: July 24, 2014, 07:16:46 pm
As he is now using a new, unidentified, display there is no way to determine if his display is wired the same way as the ones you are familiar with.

I would question - what other possible way could there be for it to be wired?  It uses a HD44780 variant; they all work the same.   smiley-eek


It looks like you are saying that because they all work the same that all of the LCD modules use the same peripheral components on their pc boards and that they are all wired the same.

Although the vast majority of the modules using the HD44780 (and compatible) controller use the same external interface and the same instruction set this similarity does not necessarily extend to the pc boards on which the displays and controller are mounted.

My original point was that just because your particular module contains 10k of resistance back to VCC does not mean that all of them do.   


Don
51  Using Arduino / Displays / Re: LCD current draw on: July 24, 2014, 05:08:15 pm
Quote
And you left the most amazing thing out, continuity check managed to lit the back light.. Sounds funny but it did

What is amazing about being able to light up an LED by connecting what is essentially a battery with a series resistor to the LED.  You have a 50% chance of lighting it up depending upon which way you apply the connections.


Quote
Also, did anyone ask for the serial of this new LCD? No, so why should i post it? Is it so difficult to ask for it ?

I thought I did ask for it in reply #27.  Also, I guess you didn't get the hint in reply #33.

Don
52  Using Arduino / Displays / Re: LCD current draw on: July 24, 2014, 02:42:33 pm
It took 5 days and 23 posts before you revealed the actual part number of your original LCD.  We wasted a lot of time on that one.

It's been 2 days and 8 posts since you got your new LCD and we still don't know anything about it.  Is there some reason that you are keeping the identification of this new LCD from us?

Your last post has conflicting information about this new display which we cannot resolve for you or anyone else reading this thread.


"This display is wired exactly as the previous one and it works great."
conflicts with
"That tells me that this LCD's back light will turn on normally if i wire the back light pins 15-16."

Don
53  Using Arduino / Displays / Re: LCD black boxes problem! on: July 24, 2014, 09:59:10 am
Disconnect the wire from pin 5  (RW) of the LCD - which you presently have connected to pin 11 of the Arduino - and connect it to ground instead.

{Technical comment - wrong descriptor for that configuration!}


We are way beyond those problems if he has followed my outline.

Don
54  Using Arduino / Displays / Re: LCD current draw on: July 24, 2014, 09:53:25 am
Quote
Contrast control works just as well with just a 5k variable resistor from Vo to the negative supply, since the module contains 10k of resistance back to Vcc and you only ever need to vary the contrast voltage a volt or two from the negative supply.

That would depend upon the specific display since they are not all the same.  As he is now using a new, unidentified, display there is no way to determine if his display is wired the same way as the ones you are familiar with.


Don
55  Using Arduino / Displays / Re: LCD black boxes problem! on: July 23, 2014, 10:21:05 pm
Quote
Maybe I need to disconnect the display while uploading the code. I read this elsewhere on the forum, please guide me about that too.
This would be a suggestion only if you are using pins 0 and 1.

I have no clue about your 'solution'.


Don
56  Using Arduino / Displays / Re: HD44780 LCD being sent incorrect data on: July 22, 2014, 09:57:32 pm
Quote
As of now, connecting the LCD like this (Pin1 to 5V, Pin2 to GND, Pin3 to GND) does not display the test display row of black squares that is expected.

Quote
I have not:
☺shorted the LCD
☺swapped the 5V and GND on the LCD

I have seen at least one datasheet for a device with +5V on pin 1 and GND on pin 2 but the vast majority are the other way around.  You haven't identified your device so we can't check this part out.

Quote
Does it matter that I am running the display in 4 bit mode and leaving the other 4 bits' date lines disconnected?
No.

It's time to start over.
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


57  Using Arduino / Displays / Re: LCD current draw on: July 22, 2014, 05:18:29 pm
Quote
And you need a 5k potentiometer between pin 3 and pin 15 to control the contrast.
Not exactly, since the potentiometer has three terminals.  I gave the connections in reply #25.

Quote
The contrast of the back light ?
No, the contrast of the LCD.

Don
58  Using Arduino / Displays / Re: LCD not displaying everything [FIXED] on: July 22, 2014, 08:03:10 am
My point is that they are the same as all the other I/O pins.  You don't have to deal with them any differently than you do any of the so called 'digital' pins.  They can even be accessed like the others, with the numbers 14-19.

Don
59  Using Arduino / Displays / Re: LCD current draw on: July 22, 2014, 07:54:53 am
Quote
... its not exacactly the same with the old one ...
Not many are.

Quote
And i will certainly need advice for the back light!!!
Make sure that we have information to get the correct datasheet so we don't waste as much time on this display as we did on the first.

Don
60  Using Arduino / Displays / Re: LCD not displaying eveything on: July 21, 2014, 07:47:28 pm
Quote
I can't see you have used any of the analogue pins, they can be used just as digital pins if you define them as inputs.
Why are you saying they have to be defined as inputs?  As far as I know they are just like all of the other I/O pins on the chip.  The only thing that makes them 'analog' pins is because the Arduino normally makes use of their "alternate port functions" (datasheet section 13.3).

Don
Pages: 1 2 3 [4] 5 6 ... 287