Spring 2000
The Society for Creative Procrastination is proud to present an overview of the enlightenment of Phi Tau Co-educational Fraternity's social fridge, Karl.

Background

About a year ago I modified Alpha Theta's microwave so that instead of going "beep" whenever a button was pressed it would instead say "ouch." This modification went over quite well with all concerned, so the obvious question was, "What's next?"

I played around with several ideas and finally decided that making a refrigerator talk every time it was opened was the best bet. This wouldn't be too hard a project: just buy a voice recording IC, attach a photocell to trigger it, and you're set to go. The only technical problem is that batteries don't like being cold, and since the device would be inside the refrigerator this would call for an external power supply. (Not a big deal.)

However, after some thought it occurred to me that it would be much more fun to install such a device in Phi Tau's social fridge, Karl, and build it such that anyone could record a message. This way, whenever the door is opened, you'll get whatever message was last recorded by any member of the house. Now these could range from a simple, "The green Jell-O is NOT social," to, well, if you know Phi Tau you can guess what all might make its way in there. :)

At any rate, given my reputation (or lack thereof) I got some money allocated at house meeting to build this device and finally got around to doing it yesterday (May 2, 2000).

Construction

Building this thing was very easy. I bought a voice recorder IC pre-assembled, a power supply, a case, a button, and some other little things at RadioShack. I then wired them up, and put them inside the box.

Here is the device from the front before assembly. Note the red record button, the black microphone, the photocell, and the power adapter plug. Oh, and the holes for the speaker.		Here are the guts of the device -- very simple really. The whole thing is just the pre-made circuit board with a few things added on.

Once the device was built, installing it in the fridge was fairly straightforward. I cleaned out the butter box (never used) in the door, and drilled some holes to run the power cord. I slipped the cord through and tied in some washers to act as strain relief. I then attached the device with three pieces of mounting tape. Whenever the amount of light in the fridge changes it plays back the recorded sound. Unfortunately this means that it does it not only when the door opens, but also when it closes. Ah well... :-)

A hint: record a brief pause in the sound to catch people off guard.

Here is the power cord run elegantly through the fridge.		On the left you can see the power adapter.

Here's a close up of the device installed. Note how elegantly the power cable is connected with a plug rather than just soldered on!		And the final result: Karl, the talking social fridge.

I hope you enjoyed this little activity. It was a lot of fun and I hope it is built well enough to last for a long time. (I also hope people don't get too pissed at me for having drilled holes in the fridge... oh well! :)