Dear All,
I have an old Keyboard with 100 keys arranged in 10x10 matrix. i want to MIDIfy the keyboard by following the method mentioned in the link below .
but these are for 32 keys and 64 keys , with a single multiplexer. for me as per my knowledge I will require 2 multiplexer ICs . what I would like to know is , what modifications do I need to make in the code to accommodate the second multiplexer.
thanks in advance ,
Alex
You need ten output pins and ten input pins. You could use an Arduino MEGA or you could use some shift registers (not multiplexers) to add output and/or input pins to an Arduino UNO. The example uses a 74HC595 8-bit shift register to drive the 8 columns and uses Arduino pins to read the eight rows. You could use one 74HC595 and three pins to get 8 of the 10 output pins. The other two pins could be Arduino pins so 5 pins to get 10 outputs. Similarly you could use a 74HC165 shift register and three pins to get 8 of the inputs. Add two more Arduino pins to get 10. Thus the scanning can be done with 10 Arduino pins. If you daisy-chain two shift registers of each type you could get 16 rows and 16 columns with six arduino pins.