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Topic: LCD keypad shield (dfrobot) doesn't work (Read 8434 times) previous topic - next topic

orive

Jun 22, 2014, 08:33 pm Last Edit: Jun 22, 2014, 08:39 pm by orive Reason: 1
Hi everybody!

Well...I've just buy a LCD keypad shield in dx and I try to work it, but I can't. I've search in google and it's supposed that the potentiometer doesn't works well.



This is the program that I'm trying to show.  LiquidCrystal Library - Hello World:

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

void setup() {
 // set up the LCD's number of columns and rows:
 lcd.begin(16, 2);
 // Print a message to the LCD.
 lcd.print("hello, world!");
}

void loop() {
 // set the cursor to column 0, line 1
 // (note: line 1 is the second row, since counting begins with 0):
 lcd.setCursor(0, 1);
 // print the number of seconds since reset:
 lcd.print(millis()/1000);
}

Do you think that the potenciometer is the problem? How could I fix it?

Thank you so much!!!

zaxarias


Hi everybody!

Well...I've just buy a LCD keypad shield in dx and I try to work it, but I can't. I've search in google and it's supposed that the potentiometer doesn't works well.

Do you think that the potenciometer is the problem? How could I fix it?

Thank you so much!!!

So it won't show anything ?  8) 8) 8) 8)
Well i don't think its the potentiometer , however you can use a PWM output instead of it..
why don't you show us the wiring..
z.p

floresta

#2
Jun 22, 2014, 10:49 pm Last Edit: Jun 22, 2014, 10:51 pm by floresta Reason: 1
Quote
Do you think that the potenciometer is the problem?

No, because you can see the black rectangles on the first line of your display.

Your display is not being initialized properly.  Are you sure that the program code is being downloaded into your Arduino?


Also, have you read the very first thread in this section of the forum?  It is the one that is 'sticky' so it always appears first, the title is 'bold' so it stands out, and it says "Warning to users of some vendors LCD keypad shields".

The particular shield that initiated that thread is a DF Robot LCD Keypad shield although it might be an earlier model than the one you have.


Don

orive

I haven't shown the wiring, because it's quite simple in this kind of shield LCD.









Also, when I launch the program, rx and tx LEDs turn on. So I think that it isn't a communication issue.

thanks!!!

zaxarias

There must be something wrong with your code,or the code is not uploaded to the board.. also i noticed your board is an arduino clone, maybe it has trouble communicating with your lcd? I dont really know...
z.p

floresta

Once again... Are you sure that the program code is being downloaded into your Arduino?

Add some code to loop() that will blink an LED to find out.  Make sure that it is a different LED or a different blink rate than the default 'blinky'.


Don

orive


Once again... Are you sure that the program code is being downloaded into your Arduino?

Add some code to loop() that will blink an LED to find out.  Make sure that it is a different LED or a different blink rate than the default 'blinky'.


Don


Yeah, I've been testing a program code with a LED and it works perfectly. I think that the LCD is defective... =(

Thanks!!!

floresta

Quote
I think that the LCD is defective.

I doubt it since you are getting the single row of blocks.  This means that it internal routines have (incorrectly) initialized the controller and your program code, which would correctly initialize the controller, has not done it's job.

Don

luisilva

I have one exactly like yours. If you post the code I try it with mine.
But I think that the problem is the code, or maybe you have 1 soldering joint not well soldered. Do you have a soldering iron?

MAS3

Hi.

Could you mention the DX SKU (article number) of this device ?
Also, show the example sketch you used.
And please put that in [code] [/code] tags.
This might shed some light on the problem, but we need both SKU and sketch.

I did receive a defective display in a similar DX offer, but that didn't show anything (no first row boxes like yours), confirming floresta's answers.
In the unlikely case this would be a defective display, my experiences with DX in such cases are positive.
But you have to be absolutely sure that there is some defect instead of a software failure.
Have a look at "blink without delay".
Did you connect the grounds ?
Je kunt hier ook in het Nederlands terecht: http://arduino.cc/forum/index.php/board,77.0.html

orive

The SKU number is 118059 and I think that it isn't a problem that it's a clone arduino, doesn't it?

Code: [Select]
// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis()/1000);
}


Thanks!!!

luisilva

#11
Jun 24, 2014, 04:00 pm Last Edit: Jun 24, 2014, 04:05 pm by luisilva Reason: 1
I still keep my point. I think is a problem of soldering. Or in the soldering of the LCD to the board of the shield or if soldering of the header to the board of the shield or even of the header to the board of the Arduino.

EDIT: I even add something more. If is a problem in the soldering joints, the problem will be in one of 6 pins: E, RS, D4, D5, D6, D7.

cattledog

Please check if there is contact between the bottom of the lcd pins and the usb connector on the uno. It looks to be metal and unusually tall.  In the photo it looks taller than the 7-15v connector and I know that on my keypad lcd shield the button pins touch that one when it is seated.

JimboZA

My DFR LCD like yours also fires up  with the black blocks. But I uploaded your code and it displays "hello, world!" on the top line with the seconds underneath.

So it's not your code.....
Johannesburg hams call me: ZS6JMB on Highveld rep 145.7875 (-600 & 88.5 tone)
Dr Perry Cox: "Help me to help you, help me to help you...."
Your answer may already be here: https://forum.arduino.cc/index.php?topic=384198.0

bperrybap

#14
Jun 24, 2014, 07:09 pm Last Edit: Jun 24, 2014, 07:11 pm by bperrybap Reason: 1
As cattledog mentioned,
Look very closely at the USB connector and U16 header pins that are also close to that connector,
when the shield is installed.
The USB connector and that header can interfere with shields.

Perhaps the LCD pins are on the connector or the pins.

I refuse to buy Arduino boards that use that type of USB connector.
There really is no need for it.

--- bill

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