I am having an issue with the a 4×4 keypad. It usually works fine but sometimes the keypad stops reacting or no key is pressed but it still shows a random keypress on the LCD. The only solution is to unplug and plug again. I thought it may be the length of the wires for the keypad. I uses 3 ft wires from the keypad to the Arduino. Has anyone faced similar issues? Diagram Picture1 Keypad

  • 3' is not that long really, but the internal pullups of the Arduino are quite weak, and you are in what looks like a noisy (electrically speaking) environment. So maybe it is EMI causing things to happen that you don't want to happen. Consider making the keypad a standalone system with a balanced communication system between that and the main box. – Majenko Feb 14 at 10:40
  • The keypad and the LCD need to be connected to the arduino. I can power 5V to the LCD from a separate source, but the keypad has to be connected to the arduino. – Merkhav Feb 14 at 12:03
  • What I am suggesting is have an Arduino (one of the small ones?) connected directly to the keypad (very short wires then), and use a serial protocol (rs232, rs485, etc) to connect that Arduino to the existing Arduino. – Majenko Feb 14 at 12:06
  • Try to test with Arduino, keypad, and LCD only to make sure that other components do not affect them. You can refer to Arduino - Keypad - LCD tutorial – Rozona Zoro Feb 16 at 7:02

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