4.5 (Key Buttons Wiring)

• Debounce for mechanical button : (boring issue with mechanical buttons)

Seems to be effective to apply 100nF capacitor on button switch
and sometimes a resistor in series without modify sketch code for accurate reading

Make your own prototype PCB with key buttons at least with capacitors
with soldered wires on PCB side

Press buttons only with fingers without having the PCB in the hand
(Conductivity of hand skin sometimes can cause problems)
Isolate hand contact from key buttons PCB

Arduino pin cabling

KEY Button	ARDUINO PIN
Enter/Select	Digital pin 1
Up/Next	Digital pin 2
Down/Prev	Digital pin 3

WARNING ! When you uploading sketch with Arduino IDE

You need momentary disconnect GND wire from PCB Key buttons

Because capacitor on PIN 1 (TX) will deny to upload sketch

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Next step see Battery Monitor wiring