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Reverse RGB LCD display 2 wire not working with Arduino Uno
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Reverse RGB LCD display 2 wire not working with Arduino Uno

by cengen on Thu Aug 01, 2019 10:50 am

Subject line got truncated: Using Arduino Uno Wifi Rev 2 with Adafruit Ultimate GPS Logger shield and Reverse RGB LCD 2 wire display

I am new to arduino development. I am using the create.arduino.cc web development tool.

I can get sketches running with the Arudino Uno and Ultimate GPS and get valid GPS data ....

I believe I should be able to supply just the four wires to the Adafruit Reverse RGB LCD display I bought and have it work with the Ultimate GPS Logger Shield.

Power and ground (ground nearest the VIN pin)
and
the I2C pins SDA and SCL

running the HelloWorld I can't get the display to light up or display anything. Seems dead.... (please see attached sketch ino file)

I have checked the LCD kit assembly quality and removed and re-soldered the 4 wires to test two times.

Q) can I used the I2C pins ? It seems the GPS is NOT using the pins and even if, I2C should share the "bus" right ?

Please advise what you think is going on, and/or what I can do to resolve this.

Regards,

Charlie
Attachments
HelloWorld_Test.ino
(2.13 KiB) Downloaded 4 times

cengen
 
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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Fri Aug 02, 2019 9:42 am

@adafruit any advice ?

Would there be a conflict with the I2C pins ?

I am soldering to the gps shield but have verified continuity to the shield header pins

thanks !

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by adafruit_support_bill on Fri Aug 02, 2019 9:50 am

Please post some photos showing your soldering and connections.

Also run the i2c scanner code and post the results here.
https://playground.arduino.cc/Main/I2cScanner/

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Fri Aug 02, 2019 10:33 am

thank you for the advice @adafruit_support_bill.

I am at work and the arduino stuff is at home but will do this tonight and post the images and results of running the code you want me to run.

Regards,

Charlie

cengen
 
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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sat Aug 03, 2019 10:47 pm

running your i2c code I got the Serial port to display:

I2C device found at address 0x60 !
done

See attached picture
Attachments
I2C_CodeResults.JPG
I2C_CodeResults.JPG (99.54 KiB) Viewed 132 times

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sat Aug 03, 2019 10:50 pm

Solder Job back of LCD
Attachments
AdafruitKitRgbLcdBackSolder.jpg
AdafruitKitRgbLcdBackSolder.jpg (337.69 KiB) Viewed 132 times

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sat Aug 03, 2019 10:50 pm

front solder with i2c and power and ground
Attachments
AdafruitKitRgbLcdFrontSolder.jpg
AdafruitKitRgbLcdFrontSolder.jpg (322.56 KiB) Viewed 132 times

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sat Aug 03, 2019 10:51 pm

Front view of Arduino Uno Wifi Rev 2 with Adafruit Ultimate GPS Logger shield and Adafruit Reverse RGB LCD display wired up
Attachments
ArduinoUnoWifi_AdafruitUltimateGps_AdafruitRgbLcd_Wiring.jpg
ArduinoUnoWifi_AdafruitUltimateGps_AdafruitRgbLcd_Wiring.jpg (347.04 KiB) Viewed 132 times

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sat Aug 03, 2019 10:54 pm

interestingly running the HelloWorld sketch from the Adafruit RGB LCD Shield Library with the contrast potentiometer turned fully counter clock wise I see the first row's 16 positions but never any characters.

if I turn the contrast potentiometer clockwise it goes full black, don't see a thing.

thanks for reviewing all this and trying to help me get this going !!
Attachments
AdafruitKitRgbLcdPoweredContrastPotFullyCCW_Powered_AndRunningHelloWorldSketch.jpg
AdafruitKitRgbLcdPoweredContrastPotFullyCCW_Powered_AndRunningHelloWorldSketch.jpg (287.37 KiB) Viewed 132 times

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sat Aug 03, 2019 11:07 pm

I also used an ohm meter to look for shorts on the LCD kit, shorts between power and ground, and the I2C SDA and SCL lines...

Didn't find any shorts

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by adafruit_support_bill on Sun Aug 04, 2019 7:31 am

The last photo with the blocks on the first row is typical if the display is not completing the initialization. It seems that you are communicating with the i2c i.o expander chip OK. The problem is likely between that chip and the display.

Looking at your photo of the back of the board, there are a few suspicious solder joints on the display header. In particular the second and fourth from the top look like they may be cold joints that have not flowed well onto the solder pad.

This guide has some tips on identifying and fixing common soldering issues: http://learn.adafruit.com/adafruit-guid ... n-problems

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sun Aug 04, 2019 2:04 pm

Thank you very much Bill....

I was thinking I should see if a cold solder joint. Based on your information I will give it a go to reheat abd get nice clean meniscus joints and report back.

Going to be at least 6 hours before I get back home again.

Regards
Charlie

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Sun Aug 04, 2019 9:37 pm

Hi Bill,

No Luck.

I have reheated and flowed both all 18 pins of the LCD header, on both the lcd side and the I2C 'daughter' PCB, as well as the four resistors and all 20 pins of the integrated circuit.

Is there some sort of repair service I can mail the reverse rgb lcd kit in for or how can you help me get this to work?

I think the LCD module is defective. Its interesting that I cannot get any of the LED backlight colors to display, not a single one, and no characters and only at fully counter clock wise do I see the 16 boxes of the first row when powered up with the helloworld ino.

I have other LCD modules that I have had for years and suspect they could be compatible, but I don't think I should just try them and don't want to keep messing with the PCB un-necessarily for fear of lifting a pcb trace or otherwise damaging the board(s)... I do not believe this is something I have soldered poorly.

So again, please tell me what can be done to resolve this issue...

Thank you!

Charlie

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by adafruit_support_bill on Mon Aug 05, 2019 6:05 am

We can try replacing the kit. Please contact support@adafruit.com with a link to this thread and we can get one out to you.

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Re: Reverse RGB LCD display 2 wire not working with Arduino

by cengen on Mon Aug 05, 2019 9:41 am

Thank you Bill. I will do that. I really appreciate your fast replies (even on the weekend !!), help and I2C sketch.

Regards,

Charlie

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Please be positive and constructive with your questions and comments.