Nate at SparkFun took advantage of a mounting place on a neighborhood street to install an interesting technical and social project:

I mentioned to my wife, ‘wouldn’t it be funny if someone put a payphone there?’. She agreed, and down the rabbit hole I went…

Ever since I was a kid I wanted to take apart a payphone. The first time I called my parents for a ride home from a payphone outside the movie theater, I noticed the screws and the locks. I had basic knowledge of screws and these were obviously hex bolts, but what were the pegs in the middle? Fast forward 30 years and obviously everything has changed. You can buy security screw bits at the local hardware store, and payphones are a thing of the past, but the retro curiosity was still there. If I was going to covertly put a payphone out on the street, we better make some people giggle before we get in trouble.

The 970-HA-JOKES Payphone Project is an Arduino based, fully functional, payphone that utilizes VOIP over WiFi, with a bunch of easter eggs built in.

Here’s how the Payphone Project worked: take a phone and make it VOIP enabled. And require that a coin be deposited before allowing the call. Oh and be really sure 911 is available and can be dialed without a coin. Also, the phone is kind of far away so the VOIP will have to be WiFi based. And there’s no power available so it will have to run on batteries. And wouldn’t it be funny if the phone played a silly MP3 if someone called 867-5309?

Check out the detailed tutorial at SparkFun.