Project 10 Crystall ball | Error | Characters don't show

[neulad]

Hi there!
I'm currently stuck in Arduino Projects book on the Project 10 called "Crystall ball".
The problem which I'm facing is that characters don't seem to show up on the LCD screen.
I tried working through some suggestions, like here:

1. 16x2 backlight works but characters don't display - #10 by floresta
2. 16x2 backlight works but characters don't display - #15 by techiefellow

Backlight and contrast work just well, however, when the contrast is set to the max it shows this instead of just squares, I don't know if it's supposed to be this way

Now, I reassembled my circuit two times, making sure pin 2-5 connect to DB7-DB4. I tried using pins 7-10 but it resulted in no success.
I followed the tutorial thoroughly, but my implementation fails.

For debugging purposes, I used a simpler code and simpler circuit, without using a tilt sensor, and currently my circuit looks as follows:

One difference that I noticed with a tutorial is that I have VDD instead of VCC, E instead of E/N and DB pins instead of D, which seems to be identical, just different names according to my google search.

All connections are stable.

Please, help me debugging it.
If you need anymore details, I will happily share it.

[neulad]

I forgot to share my code, it's right here:

#include <LiquidCrystal.h>

//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);  // put your Arduino 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() {
}

[neulad]

And the project page is here:

[Railroader]

Please post schematics, not Fritzing picture.

[neulad]

Here you go

[evanmars]

Looks like your potentiometer might be in the wrong position. What is connected to V0?

[neulad]

pot is connected to V0, and when I rotate to the max it starts showing some characters, it probably works

[evanmars]

Sorry, I see it now.

[xfpd]

This looks like a solder bridge between two pins...

And all the pins look like cold joints where the solder is stuck to the pin, but not touching the pad. Reflow all pins with flux.

[neulad]

That's true! Thank you for mentioning it, it is actually this way, but it was this way originally and I haven't done it myself

[xfpd]

@neulad

it was this way originally

Fix it.

[neulad]

Don't you think it's supposed to be this way? Do you think it's a manufacturing defect? I don't have anything to "unsolder it" right now

[xfpd]

@neulad

"unsolder it"

Not "unsolder" but "re-heat all the blobs until the solder flows and attaches to the pin and the pad."

@neulad

I don't have anything

Purchase: (1) Digital Multi Meter, (2) Solder Iron for Electronics, (3) 60/40 Rosin Core Solder (4) Liquid Flux

[neulad]

Thank you, that's really useful
One thing, I think I might be able to just break this bridge with some knife, it's a tiny bridge.
Let me know please if you are sure it's a defect and it shouldn't be this way, I see on other images it's indeed not supposed to be connected, is it the case?

[xfpd]

@neulad

Let me know please if you are sure

To be sure, I would measure DB4 to DB5... with a DMM... if no resistance, it's a short. All the other solder joints look just as poorly done. That's all I can guess looking at a picture.

If you will be using a knife, be careful not to slip and damage other connections.

@neulad

I don't have anything

Are you in a school with electronics course? Maybe you can bring it to a phone repair, where they solder every day. Maybe they will let you watch so you can learn? That would be nice for you learn to solder.

[neulad]

I got it, thank you!
I will use a knife, if I damage it I will just buy a new one, it seems to be defected any way

Will buy DMM too, thank you for this advice. I will need it in the future, no doubt

No, I actually doing it on my own, so I really appreciate your advice
I will bring it to the phone service in case breaking a bridge doesn't help
Super helpful post, I appreciate it!
Will post again if I manage to fix it or not!

[J-M-L]

where did you get this LCD from then ?

[neulad]

Arduino Starter Kit R4

[build_1971]

If it was in the box with the book, you might return it for a better one....

[J-M-L]

looking at this kit's picture, It does not seem that the LCD comes with the headers soldered. Someone might have done it for you?