(keypad: columns and rows switching) So now you can see how the button presses can be translated into electrical data for use with a microcontroller. We can now start the real experiment with as ...

The phone consists of an Arduino Pro Mini, a MP3/WAV trigger, and the phone itself, of which the earpiece and keypad have been reused. [Sam] had to map out the keypad and solder leads connecting ...

[Sam] had to map out the keypad and solder leads connecting the various contact points of the phone’s PCB to the Arduino’s digital pins.