Hello
i try use the shield but when i upload to my arduino never work if someone can help me i appreciate
Hello!
Make sure you use dox/lcd-button-shield v.0.0.5. The other version (button-shiled) was a test and i can not delete the files at the moment easily. 
Have a look at the schematic:
https://www.dfrobot.com/wiki/images/a/a7/LCDKeypad_Shield_SCH.png
The buttons are not connected directly to different input pins. There is a resistor network connected to analog input A0 and every button changes the voltage on this input.
The buttons-node outputs a boolean value (true / false) depending on the pressed button. E. g. you press the “Up”-button output “Up” becomes true.
If you want to make a test:
Open the "shield"
Connect “Up” to "L1"
Connect “Down” to "L2"
Upload to the Arduino
If you press “Up” Line 1 in the display shows “true” otherwise "false"
If you press “Down” Line 2 in the display shows “true” otherwise “false”
If there are no characters at all turn the contrast potentiometer! 
1 Like