Sparkfun WAV Trigger

When starting to review this audio replay unit, I didn't expect much. Often, they're simple, with low performance, and pretty barebones. But a closer look at this unit by ex-Disney Imagineer Jamie Robertson shows that it's really well thought out.

Mr. Robertson needed a player with flexibility and lots flexibility, so he worked Sparkfun modules into something... close.  With the WAV trigger, he's pulled together a very impressive module that should easily satisfy most hacker sound projects.

The WAV Trigger uses 16-bit, 44.1kHz uncompressed WAV files - the same specification as audio CD files. It's combined with 16 trigger input lines and 14-channel simultaneous playback, so you can easily create a 2-octave playback instrument with impressively clean sound. Pipe the output through either a 1/8" headphone line-level jack or the amplified mono speaker output.

Had other thoughts on how to control it? It includes both a serial interface line and MIDI port. This unit can create some impressive effects, as you can start multiple tracks at the same time, fade-in, fade-out, and cross-fade between tracks.

Some playback units are pretty stringent on naming conventions and how to structure the files on the SD card. The WAV Trigger also uses an SD card but manages the configurations through an ASCII INI file stored with the media files. Usually, an INI file means hand-editing, but Mr. Robertson has also created a management tool that makes configuring the WAV Trigger very straightforward.

Specifications

• Supports up to 2048 uncompressed 16-bit stereo WAV files up to 44.1kHz – CD quality
• Polyphonic! Play and mix up to 14 stereo tracks independently and simultaneously
• Sample-accurate starting and playback of up to 14 parallel stereo tracks
• Trigger-to-sound delay: 8 secs typ, 12 msec max
• MIDI control: Velocity-sensitive triggering of up to16 banks of 128 tracks
• Real-time playback rate control and MIDI Pitch Bend
• Pause and resume individual or groups of tracks. Multiple random trigger ranges
• True line-level stereo output: 2.1V RMS ground centered, 100dB SNR
• On-board mono audio amplifier and speaker connector: 2W into 4 Ohms, 1.25W into 8 Ohms
• 16 trigger inputs are individually adjustable for contact closure, 3.3V or 5.0V control
• Trigger inputs can be individually inverted, and/or set to be edge, latched or level sensitive
• Volumes adjustable from +10dB to -70dB in 0.5dB increments
• Firmware volume fades (attacks & decays) and cross-fades
• A dedicated “Play” status digital output pin
• 3.3V and 5.0V output pins
• Extensive serial control. Arduino library available. Pin compatible with SparkFun FTDI Basic

WAV Trigger Demonstration

Additional Documentation

• Hookup Guide
• User Guide
• Demo Video
• Firmware Updates and Utilities
• Product Page
• GitHub

• [Data Sheet]: Datasheet (STM32F405RGT6) Jun 2013
• [Schematic]: Schematic - Jan 2014
• [Documentation]: Eagle files