Use onion omega2 with 16 keys membrane switch keypad matrix 4X4 buttons
python 2.7
###Keypad R1 = Omega2 GPIO 0 ###Keypad R2 = Omega2 GPIO 1 ###Keypad R3 = Omega2 GPIO 2 ###Keypad R4 = Omega2 GPIO 3 ###Keypad C1 = Omega2 GPIO 18 ###Keypad C2 = Omega2 GPIO 11 ###Keypad C3 = Omega2 GPIO 8 ###Keypad C4 = Omega2 GPIO 9
10 pcs High Quality 4x4 Matrix Array 16 Key Membrane Switch Keypad Keyboard Control Panel Microprocessor Keyboard for Arduino
US $5.30 / lot 10 pieces / lot , US $0.53 / piece)
Copyright 2017 Michael Jentsch
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