Picture of Hack any Phone!
Inspired by R10n & his "Mission: Impossible - Pendeli" Geocache, (http://www.geocaching.com/geocache/GC2NQ9A_mission-impossible-pendeli), we decided to create our own version:

Any good old analog phone will do, the bigger the better. Using an Arduino & a wave shield, you can make the phone behave any way you want & even fool someone into thinking they have reached an actual number and they are listening to a voice-mail.

This project can be done in a few hours and for very few dollars.

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Step 1: Gather the materials

Picture of Gather the materials
We enjoy going to yard sales & estate sales and have found numerous telephones for $2 - $4. Even found one for $1.
We used 1 Arduino Uno & 1 Wave Shield for the first phone. With a 9 Volt battery, you have power for a very very long time.

The phone original keyboard was defective (didn't want to spend too much time to find replacement keys/fixing it) so we had to substitute it with a Membrane keypad in this case.

Step 2: The Hack...

Picture of The Hack...
Wave Shield Pinout.JPG
Handset Switch.JPG
Opening this type of phone could not be easier: 2 Philips screws underneath is all that keeps the top in place.

This exploit is made possible by simply cutting from the phone PCB the white & green wires that go to the handset speaker and connecting them to the speaker output of the Wave Shield.

Then, you cut one wire (I used Black) of the 9 Volt battery connector (somewhere in the middle) and solder each end to each side of the handset release connection (how the phone knows if he is off-hook or hangup). This will prevent any power to be used when the phone is NOT in use.

Like I said, in this case, it was easier & quicker for this application to simply add a membrane keyboard than fixing the original AT&T keypad.
Reminds me of the "chinger" we made (well mostly my friends) to use with pay phones! Pre-cell days. You guys are great!
robot7971 year ago
what if you add this to a rotary phone and make a cell phone out of it?
ST-Geotronics (author)  robot7971 year ago
robot797, I love where you're going with this. Totally doable & way cool!!