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16 x 2 LCD keypad Shield -V2.1 buttons not working


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#1 Joshua Benore

Joshua Benore


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Posted 26 January 2017 - 06:12 AM



I have a new LCD shield and testing it out for the first time. I copy and pasted two different programs (a button test for this unit and a program to adjust the brightness of the screen using the buttons) to the Arduino and it looks like it is working normally except none of the buttons are responding at all on either program.


My understanding on the mechanism:


After reading about the shield it looks like all of the buttons are using the AO (analog in) pin at different voltages. I assume that this works by different volt resistors on the buttons so that just one pin can receive input from all 5 buttons via these different voltages.


Work so far:


I found the Library for LCDKeypad as my Arduino and added it after the program initially failed. I then realized the Arduino program needed to be restarted before the changes could take effect. Also unplugging the the Arduino and reconnecting it to clear the averdude errors (Arduinos can be a bit eccentric).


Hypothesis of diagnosis:


The pin going into the A0 is a little bit longer than the other pins which I would not assume be an issue unless it was SHORTER than the other pins. I don't know if it is just an anomaly of the manufacturing process or this pin is intentionally about 1/2 millimeter longer than the other pins to ensure connectivity.


In quarry:


Before I do anything drastic like cutting the extra length off of the LCD sheild's pin to AO, I will first find a way to test the AO input on my Arduino Uno to make sure it is not my Arduino's input port malfunctioning. Any input or ideas for troubleshooting this cool little toy would be appreciated. I will respond with a solution if found for the sake of the product's quality assurance. 

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