Every Halloween, inexpensive talking skulls are available as decorations. They look good, but they have a tiny speaker inside them, making them hard to understand. And they only say a few pre-programmed things. What if you could hack one so that you could make it say anything you want? And have it work with any speakers you own?
Here's what one that I got says. Notice that I have to snap my fingers at it to get it to play. Also, he doesn't just talk - he's got his own sound effects and music as well. I think this makes him harder to understand.
Some friends and I worked out how to do this inexpensively; as a matter of fact, this is the least expensive way possible to do this. These talking skulls are usually about $20.00 new, and less off-season. Other versions of this project on the web use parts that cost lots more than the skull!
Here's a quick explanation and demo:
We made a custom-designed circuit that needs less than $5.00 of parts – plus we’ve arranged with a company to offer a professionally printed circuit board so you can assemble it like a kit, instead of working out how to build it on prototyping board. The professionally-made board is quite reasonably priced, and can be bought as a bare board where you supply the parts, as a kit with the parts, or assembled (see step 2 for details).
How it works: The circuit inside the skull is replaced by a small, custom-made board that will respond to “beeps” on an audio track; when the circuit hears a “beep” it turns on the motor in the skull, opening the mouth.
It’s a great project paired with a microcontroller (Arduino, EFX-Tek Prop-1, or Picaxe) that can trigger the playback of an MP3 or WAV file.
This is a multiple-part project, and you should have some experience in hobby electronics: Reading circuit schematics, soldering, assembling circuit boards, editing sound files on your computer, and programming a microcontroller to play back MP3s when you want.
2014 update: Someone asked if you could use this live with a microphone, so you could be hidden somewhere, and have a skull that is sitting on a table talk to people and react to what they say. Great idea! Yes, you can - there's a simple way (and it's easier than the original project!) Go to "Testing the skull" and see the notes at the bottom of the page.