A recurring theme that I’ve posted about here is the quest for a “rar box,” a device that’s small enough to hide in a costume that could be used to play back monstery sound effects. A previous post
mentions the Adafruit Wave Shield, which was a pretty good solution (video of it in action
) if you’re comfortable with a fair bit of soldering and a little bit of programming.
SparkFun Electronics now sells a unit called the MP3 Trigger
which is a slightly less daunting version of the same idea. If you can solder just a few trigger switches, everything else has been taken care of. You load up a MicroSD card with a few MP3 files (named TRACK001.MP3, TRACK002.MP3…through TRACK007.MP3), and each sound will be automatically triggered in response to a closing of the corresponding switch.Pros:
No programming required. Slim, single-board design. A few dollars cheaper than Arduino + Wave Shield combination. Less soldering. Better sound quality (16-bit MP3 vs. 12-bit WAV). Stereo sound; with clever placement of speakers and corresponding careful sound design, you could have audio effects emanate from different parts of the suit (e.g. put the “left” speaker in the muzzle and the “right” speaker under the tail, then design the sound files with roars and yips only using the left channel, and fart noises only using the right channel).Cons:
Limited to seven triggered sounds (tech-savvy types can trigger up to 255 sounds with an external microcontroller, though this negates much of the simplicity). Less flexible triggering options; mostly limited to momentary pushbuttons, other switch types (e.g. magnetic Hall-effect sensors) may require some changes (or again, a separate microcontroller).
In either case (Wave Shield or MP3 Trigger) you still need to add some stuff:
- A FAT16-formatted SD card (Wave Shield) or MicroSD (MP3 Trigger) to hold the sound files.
- Amplified speaker(s) to play the sounds (various portable iPod speakers work great for this).
- 9V battery to power the board.
- A sweat-proof enclosure for the device and battery.
- Trigger switches and wire (see the “in action” video above for an example).
Neither system is capable of polyphony; they can play only one sound at a time. With the MP3 Trigger, a new sound triggered will interrupt any other sound currently playing. With the Wave Shield, since it’s Arduino-controlled, this will depend on how you program it — you can either interrupt the currently-playing sound, or not allow other triggers until the sound has finished playing.