Hello!
I am following the instructions from the Adafruit tutorial to make my LCD screen (16x2) connected with the Arduino to display some characters, but I cannot make it. I can only see the white boxes on the first row and half of the second row. Do you have any suggestions on what is going wrong?
You can find attached my circuit. The sketch is the one from the Liquid Crystal Library Hello World!
Thank you so much in advance!
Kind Regards!
compressjpeg.zip (1.05 MB)
The LiquidCrystal library is set up so that you can assign any Arduino pins to any LCD pin. Your photo is taken at such an angle that it is impossible to determine which Arduino pins you are using but it seems that the pins you have used are not the ones that were specified in the sketch that you referenced.
You will have to change either the wiring or the sketch so that the pin usage matches. It is the 'constructor' that is the key to doing this. It is unfortunate that the perpetrators of the Arduino sketch did not include appropriate comments.
//LiquidCrystal lcd(RS, E, D4, D5, D6, D7);
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // put your Arduino pin numbers here
Don
You are hooked up to pins 7,8,9,10,11,12
Change
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
to
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
Looking at the picture, I join @INTP.
If you still don't see anything, play with the contrast.
I can only see the white boxes on the first row and half of the second row.
I forgot about this part. The fact that he can see white boxes means that the contrast is acceptable. The boxes on half of the second row is something I haven't come across previously and is troubling.
Don
Thank you all very much for your time and your help! That was my first post ever and I guess I didn't do the best job ever! I have altereded the code accordingly (LiquidCrystal lcd(7, 8, 9, 10, 11, 12);), (that's the only thing I changed in the original code by the way) but I cannot see any characters. I also measured the voltage at all pins with my voltmeter and everything seems fine! I also played with the contrast (using the pot) but still nothing. Is there a chance my lcd screen is faulty?
compressjpeg.zip (1010 KB)
Yes there is a very tiny chance the lcd is broken but there is a much higher chance you made a mistake elsewhere.
Have you done any prior projects with your Arduino?
What do you mean " measured the voltage at all pins with my voltmeter and everything seems fine! " ?
What is the exact type of your 16x2 LCD? It looks a little bit different from my lcd displays.
And: did you check all your soldering very carefully ?
Sometimes a bad soldering causes strange lcd behaviour, so it might be a good idea to heat the solder spots again.
Yes, I have done some other projects with the Arduino. I am working with the Arduino for 6 months now.
The voltages at the pins tied to ground exhibit 0V, those tied to Vcc exhibit 5V, and the data lines exhibit a voltage between these two values.
My 16x2 character LCD is the one from Adafruit (16x2 Blue LCD #181 (Standard HD44780 LCDs) ).And yes I have already checked the soldering and reheated the solder spots.
Thanks again!
Thanks guys for all your help!!! I really appreciate it!
I found what was wrong after two days of troubleshooting and all of your help!
There was one cable I used that it was broken. I checked all my cables for connectivity with the multimeter and I discovered that there was one broken, though it seems perfectly fine!!
Now the whole project works fine!!
Glad you got it working.
Your second photo still does not show the Arduino pins but it does show several things that we couldn't see before which would have helped get a quicker diagnosis.
First of all it clarifies the statement "I can only see the white boxes on . . . half of the second row." I interpret half a row as either the left half or the right half due to how the device works internally. Your display shows 3 out of 7 horizontal rows of pixels which is a completely different situation.
With the right or left half not working there would almost certainly be a problem with the display itself. In your situation it means that the device is improperly initialized as a 1-line display which is typically due to improper programming or improper wiring.
What we should have picked up on earlier was the use of those prefabricated jumper cables which unfortunately are frequently faulty as you have found out.
Don
EDIT: Your display will be clearer if you remove the clear plastic film.
Congrats as well!
My experience says that only very rarely a lcd is really broken (DOA).
Most common issues are:
rpt007:
Congrats as well!My experience says that only very rarely a lcd is really broken (DOA).
Most common issues are:
- programming issue (wrong initialization of the constructor)
- forgotten GND or +Vcc
- bad soldering at the display
- wrong position of contrast potentiometer
- broken cable - although I hadn't any problems so far with the prefabricated cables
Thanks again guys!
floresta:
Glad you got it working.Your second photo still does not show the Arduino pins but it does show several things that we couldn't see before which would have helped get a quicker diagnosis.
First of all it clarifies the statement "I can only see the white boxes on . . . half of the second row." I interpret half a row as either the left half or the right half due to how the device works internally. Your display shows 3 out of 7 horizontal rows of pixels which is a completely different situation.
With the right or left half not working there would almost certainly be a problem with the display itself. In your situation it means that the device is improperly initialized as a 1-line display which is typically due to improper programming or improper wiring.
What we should have picked up on earlier was the use of those prefabricated jumper cables which unfortunately are frequently faulty as you have found out.
Don
EDIT: Your display will be clearer if you remove the clear plastic film.
Thanks again! Now I can move on building my mini portable meteorological station!