I saw the start of Fabienne Serriere’s awesome project at the Maker fair – here’s the how-to! She writes “This How-To is the first in a series of construction instructions for a project titled The Magic Phone. I was inspired by the Port-O-Rotary from Spark Fun but wanted to take the project to the next level and with hardware I already had on hand. You may be able to extrapolate these instructions to different models of telephones, different telephony protocols, and even different projects.” Link.
HOW TO – The Magic Phone: Number Pad Matrix Decoding