Diana Eng and I hacked a Star Trek (TOS, thank you) communicator toy, making it into a bluetooth speakerphone for use with a cell phone. You can read about it at makezine.com.
We made a few minor enhancements since the article was first published, most notably adding an LM4890 audio power amplifier to get more volume from the speaker. Here is the updated schematic:
You can download the sourcecode and schematic here: tosscom.zip.
