20 Pin Header
Next, solder the two 20-pin
headers to the back of the
button board. It is best to first
solder the two outer pins and
then the remaining pins.
2
4x4 Keypad
Now place the 4x4 Button Key-
pad on the front of the Button
Board. Make sure that the holes
on the keypad match the holes
on the button board.
3