"Hello world" is not displaying on LCD; Even my LCD doesn't get power.

Sorry, but that's another bad LCD.

There's really nothing you can do wrong that would result in missing pixels in your LCD display. I'd try another one again.

I disagree here (sorry). First thing you can do wrong is what happened here: Throw some wires in the direction you think they belong and hope it will work. It will not, or with very strange errors. Take a look at the last photograph. There's a lot of space between the jumper wires and the holes in the module's PCB. This is a guarantee for huge problems, and i'm confident that that is what leads to the strange performance of the LCD. What if the contrast pin (3) is very noisy because of a very poor contact ?

Admittedly, those wires to the lcd don't look like they're soldered.

You have to solder wires that aren't on the breadboard, otherwise you have random electrical connection.

What I see in the most recent photo is that the instructions in the LiquidCrystal tutorial given in reply #1 were not followed. If you look on the LiquidCrystal tutorial page:

Before wiring the LCD screen to your Arduino we suggest to solder a pin header strip to the 14 (or 16) pin count connector of the LCD screen, as you can see in the image above.

Simply put: Wires not soldered to LCD module == Poor electrical Connections. Poor electrical connections == Things may or may not work correctly.

As far as the missing pixels go, it looks like it could be loose connections to the actual LCD glass on the elastomeric connector. http://en.wikipedia.org/wiki/Elastomeric_connector If you press on the LCD does it change or get better? If so, you could try twisting the tabs on the back of the module that hold the frame. Twist them just a bit to tighten them - normally clockwise - and see if it helps.

--- bill

jabirfatah91: I wired everything once again, but it is behaving still in the same way. No light on the display, only the first row is lit up (if u have a closer look on my LCD, u will see).

In the "broken" LCD photo in this reponse: http://forum.arduino.cc/index.php?topic=206035.msg1517558#msg1517558

I see what looks a LCD that is wired up incorrectly or not completely wired up. From the datasheet diagram, the pin order is:

14, 13, 12, 11, 10, 9, 8, 7. 6, 5, 4, 3, 2, 1, 15, 16

Looks to me like: It is hard to tell exactly how it is wired due to some parallax issues. But for sure there is only 1 set of power connections vs the 2 needed. and then the r/w line (LCD pin 5) does not appear to be wired up.

From the photo I can't tell if the backlight is not wired up or if all the control lines are shifted over by 2 pins.

Either way, the way that is wired up, it isn't going to work and you may not see anything if the backlight power connections are not hooked up.

You need to wire up the backlight power to turn on the backlight to be able to see the pixels on that display.

NOTE: You may need to use a resistor on the backlight. I'd use like a 100 to 330 ohm resistor to be safe.

--- bill

The most recent photo shows that the backlight is now wired up and operating.

Unfortunately, the sporadic missing pixels cannot relate to poor data and control connections to the module, but more likely to the internal “Zebra connector” as observed by bperrybap. It may be possible to “fiddle” the LCD assembly to fix this (at the most extreme, undo the tabs, disassemble and reassemble the LCD panel).

Given the problems with making less than positive connections, it is possible that the previous display would work if everything was connected suitably, but this unfortunately seems to have been anything but a straightforward exercise. :smiley:

Admittedly, those wires to the lcd don't look like they're soldered.

You have to solder wires that aren't on the breadboard, otherwise you have random electrical connection.

And off course, I must admit it that the pins were not soldered with the module and that causes some disappeared pixels on the display. There is no doubt that it's just because of that. Moreover the current flow becomes random because of that. I, however, feel that this issue can be fixed by later by soldering. At least I am satisfied that this time my connection walks on the right way.

Well, you definitely have to solder those connections.

After you've done that, get back to us with what's happening.

Paul__B: The most recent photo shows that the backlight is now wired up and operating.

From what I can see, there are two differenct LCDs being used. The "new" one uses the more typical pinout and that one has the backlight hooked up and seems to be working other than the pixel issues - which is not going to be fixed by soldering.

The "original" one in this response: http://forum.arduino.cc/index.php?topic=206035.msg1517558#msg1517558 which was said to be "broken"/"damaged"/"bad" is the one I'm seeing wiring issues.

That one looks like the backlight is not hooked up. (probably needs a resistor to limit the current) It also looks like the r/w line is not hooked up either.

--- bill

As I previously stated, I believe both LCDs are broken. Get another one, and use solder.

arduinodlb: As I previously stated, I believe both LCDs are broken. Get another one, and use solder.

I saw what appeared to be wiring errors in the photo of the first LCD in this post: http://forum.arduino.cc/index.php?topic=206035.msg1517558#msg1517558

Are you saying you wired it up differently than the photo you showed us?

Or are you saying that the backlight is wired up and that the r/w signal on LCD pin 5 is hooked to ground and we just can't see it in the photo?

I don't see the backlight power signals and the ground signal for R/W in that photo.

--- bill

Even with incorrect wiring, he couldn't get the results he was getting.

arduinodlb: Even with incorrect wiring, he couldn't get the results he was getting.

I disagree. Again I am talking about the first LCD. (Not the 2nd one with the missing pixels that is "working" and has the backlight on) From the last photo of the first LCD, the backlight was not hooked up to power. Also I can see in the photo that the LCD r/w line is not hooked up. (With the LCD r/w signal floating, the display cannot be initialized.)

So, I see a photo of a display with the backlight off that is not initialized or at least not showing the expected contents. To me, the photo shows conditions that woud be consistent with conditions I'd expect to be created by the incorrect wiring shown in the photo. So I don't see anything yet that indicates to me that the first LCD is broken. Only incorrect wiring so far.

--- bill

bperrybap: So I don't see anything yet that indicates to me that the first LCD is broken. Only incorrect wiring so far.

I'm with that.

And - the pixel problem in the second one has absolutely nothing to do with wiring.

The last pin on the LCD is LED- and the pin next to it is LED+. this will power backlighting. I recommend using a 10K resistor to prevent damage Also check This image for correct wiring The LED wires are not displayed in the image, but they work guaranteed!

Hope this helps!

jkctech: Hope this helps!

It doesn't help, in fact it creates more confusion, because the LCD in that drawing is not the same pinout as the LCD we are talking about. Read the thread from the begining as much of the early part of the thread was talking about pinout of the first LCD.

What we have seen so far is that jabirfatah91 had a LCD with a pinout that is less common than most of the LCDs out there. It was wired up incorrectly a couple of times and then declared "bad".

Later in the thread a 2nd LCD was used, which used the more common pinout (the one shown in the diagram you posted) and that LCD was wired up correctly and worked.

But since the first LCD has never been wired up correctly, there is no way to really know if the first LCD is really bad or has just been incorrectly wired up.

--- bill

jkctech: I recommend using a 10K resistor to prevent damage

For backlighting, 220 ohms.

Other matters as bperrybap explains.