A lot of making goes on in this community these days, but sometimes you’ve just gotta do some old fashioned hacking. You might have grabbed an old Speak and Spell that you want to repurpose ...

Analog Devices, Inc., has introduced a mobile I/O expander and QWERTY keypad controller with ambient light sensing for smart portable devices that require a large keypad matrix and expanded I/O lines.

The ADP5589 is an I/O port expander and keypad matrix decoder designed for QWERTY type phones that require a large keypad matrix and expanded I/O lines. I/O expander ICs are used in mobile platforms ...

This idea builds on a previous IFD, "Connect Any Keypad With Any Microcontroller Using Only One Pin" (electronic design, May 1, 1998, p. 126), where a 555 timer connects a keypad switch matrix to a ...