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16x2 LCD: characters not showing
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16x2 LCD: characters not showing

by nojp on Tue Jan 08, 2019 2:20 pm

Hi,

I've bought and put together the "Adafruit RGB 16x2 LCD + Keypad Kit for Raspberry Pi". I went by the assembly guide and managed to get everything in check.

I've connected the contraption to the Pi 2 B+ using the 26-pin header and I2C has detected it at address 20, so that's fine. I've put together an example py script, and here's where the issue comes into play: the backlight works (any color), but casting a message to the LCD has absolutely no effect, nothing shows up.

I've went over the soldering and triple checked everything is soldered properly and that no two points are connected where they shouldn't be.

Where am I making a mistake? Is it possible the unit could be faulty?

Thanks for any responses.

nojp
 
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Re: 16x2 LCD: characters not showing

by millercommamatt on Tue Jan 08, 2019 5:49 pm

Let's see your code and some pictures of the connections.

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Re: 16x2 LCD: characters not showing

by franklin97355 on Wed Jan 09, 2019 1:02 am

Have you tried adjusting the contrast?

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Re: 16x2 LCD: characters not showing

by nojp on Wed Jan 09, 2019 4:23 pm

Hi again,

yes, I've tried adjusting the contrast, it was to no avail. The code I used is the most basic example from the set-up guide. Here are some photos.

118c2020-f59d-46ec-9005-532b9ac26781.jpeg
118c2020-f59d-46ec-9005-532b9ac26781.jpeg (111.37 KiB) Viewed 58 times

277e1eea-cc05-4d14-843d-c8f6e25d4fc1.jpeg
277e1eea-cc05-4d14-843d-c8f6e25d4fc1.jpeg (105.23 KiB) Viewed 58 times

a896592d-358d-453b-b345-6f06f1ce6087.jpeg
a896592d-358d-453b-b345-6f06f1ce6087.jpeg (94.74 KiB) Viewed 58 times

nojp
 
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Re: 16x2 LCD: characters not showing

by ckelly321 on Sat Jan 12, 2019 11:24 pm

I am having the exact same problem. At first the contrast was turned up too high and I could not see the characters being displayed. Then I tweaked the potentiometer to dim the backlight so that I could see the characters. After dimming the backlight I could see where the characters were "being displayed", but instead of the lcd.message("It works"), that I expected, each character was filled in entirely, such that every character was filled in with every pixel. (picture attached). I am using part number 1107;howevever, I cannot find it available for sale, so I have been using the 1109 guide.
Attachments
Scanned_20190112-1912.pdf
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