Paul and Greg of asked me to hack their roboraptor and so I obliged. A nice distraction from my usual weekend projects.

I tacked a Softbaugh demo board that I had lying around on top of the robo contoller board to hijack the sound. By adding a small interface board I was able to trigger the demo board sound playback whenever dino roared.

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This a closeup of the header that I soldered into the position of the S8050 transistor. The S8050 was moved to the interface board to amplify the demo board output.
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The native robot sound signal switches the 2N3904 transistor of the demo board via the op-amp comparator. When the transistor turns on it grounds switch 2 of the demo board and initiates the sound playback. The S8050 is reused to amplify the DAC output of the MSP430F169 however the original robot sounds can be restored simply by pulling the S8050 from its machine socket on the interface board and plugging into the molex connector that comes from the header connector shown above.
Power for the interface board and Softbaugh board comes from L1 of the robot pcb (2.5V). The inductors might not be essential but I wanted to minimize any motor transients in the power lines.
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The 2N3904 is a SOT-23 package and all resistors are SMT.
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