Features

• max 44khz, 16bit wav
• supply voltage 3,3V to 5V
• dimensions 2,5 cm x 5 cm
• upgradeable firmware, AVR AtTiny861 based board
• 16bit output created from 2 shifted 8bit PWM channels, good quality
• output for amplifier
• can driving small speaker, amplifier is recommended
• all control signals on header active in low
• 8 buttons for testing (optional sold without)
• no arduino required, standalone operation
• micro SD card push-push connector
• sold without micro SD card
• recommending 1000uF capacitor to supply voltage to cancel some card reading noise

Trigger Mode

Supported sound file format is RIFF/WAVE in LPCM, 8/16bit, mono/stereo and 8kHz-48kHz. Any other sound files, such as ADPCM, MP3 and AAC, must be converted into the PCM. The sound files must be named NNN.wav. The NNN is three digit number in range from 001 to 255. The sound files must be put into the root directory.

The control command is input as binary code by eight contacts (SW1-SW8) and the corresponding sound file will be played. e.g.

• SW1 corresponds to 001.wav
• SW4 corresponds to 008.wav
• SW1+SW5 corresponds to 017.wav.

There are four operating modes, behavior of the sound generator on control command, can be configured by 000.txt on the root directory.

Each mode works as follows:

• Mode 0 : Level trigger Plays a sound file corresponds to the input code in auto-repeat. When the input code is changed, the sound also be changed. When the input goes off(0), the audio output is stopped.

• Mode 1 : Level trigger (sustained) Same as mode 0 but the file is played until end of the file and then stopped when the input goes off.

• Mode 2 : Edge trigger Plays a sound file corresponds to the input code once. Any code change while a sound will be ignored.

• Mode 3 : Edge trigger (re-triggerable) Same as mode 2 but the code change is accepted while the sound. To re-rtigger with the same code, change input to 0 and then input the code again.

• Mode 4 : Edge trigger (stop on release) Same as mode 2 but the sound stops when the input goes off(0).

LED indicator

The LED indicates that a sound file is being played. It also flashes on any error. The number of flashes + a second of blank corresponds to the type of errors as follows:

• Two fhash - I/O error. (hard error or file system error)
• Three flash - The sound file is not found.
• Four flash - Invalid sound file.

Based on Elm Chan design. Sound quality is much better than 8bit players but not CD.