SparkFun Forums

[Webbie]

Hello Jamie,

Last week I've bought the WAV Trigger board and the SparkFun FTDI Basic Breakout - 5V.
Everything works fine with the Wav Trigger Remote, but have one problem.
(I've read all the documents at the product page)

I don't get the communication working between a terminal console program (Putty, Termnial, YAT, etc.) and the Wav Trigger board.
I've set the program to 8N1, 57.6K baud and tried both the ASCII and Binary settings.
Files on the SD card are in this format: with 001xxx.wav, 002xxx.wav, etc..
The used program indicates that's connected, but won't react on the for example "0xf0, 0xaa, 0x08, 0x03, 0x01, 0x0a, 0x00, 0x55" string to start an audio-file from the terminal console. I've also tried the "f0 aa 08 03 0a 00 00 55" string, no response.

What I'm doing wrong?

Help would be much appreciated.

Greetz Webbie...

[robertsonics]

I don't know enough about those console programs to help with the specific format they use for entering binary data. Your first example should play track "010xxx.wav" in poly mode, but your second example appears to have a typo, since "0x03, 0x0a" isn't a valid CONTROL_TRACK option.

Have you downloaded and run the Remote Control example app to make sure that your serial connection is working? You can also look at the code in the Arduino Serial Library to see additional examples of how serial messages are constructed.

Edit: Sorry, you did mention that the Remote Control app works - didn't read carefully enough. What you're doing certainly should work - perhaps it's how you are entering the data in the console app.

[Webbie]

Hello Jamie,

Thank you for your reply.
I've finally found the right software that worked out-of-the-box with the WavTrigger (and SparkFun FTDI Basic Breakout - 5V), I'd only filled in the port credentials.
The program I've found is CoolTerm, which is available for Linux, Mac and Windows.

http://freeware.the-meiers.org/

Screenshot CoolTerm.


For my project the WavTrigger was the third sound module I've tested, the two others were SmartWave (also a wav-player, but very bad sound quality and lots of audible artifacts/noise) and the Somo-II (MP3 player, good sound quality, unfortunately won't play wav-files).

From left to the right, Wav Trigger, Smart Wav en de Somo-II.




Below some screenshots of my measurements (taken with Smaart V7 DI):

Somo-II sound module, spectrum analysis (taken with "pink noise").



SmartWav sound module, spectrum analysis.


Legend (from bottom to top):

• DARK GREEN = player paused
• PURPLE = player plays wav-file with "silence", lots of audible artifacts/noise
• LIGHT GREEN = player plays wav-file with "pink noise"
• RED = player plays wav-file with "white noise"

WavTrigger, spectrum analysis.


Legend (from bottom to top):

• DARK YELLOW = player paused
• GREEN = player plays wav-file with "silence"
• BROWN = player plays wav-file with "pink noise", substantial mid/high roll off
• RED = player plays wav-file with "white noise", substantial mid/high roll off

For my project it is important that the sound module is of high quality and capable of producing 20 Hz - 21,5 kHz.
Although the substantial roll off of the mid/high (resulting in colorization of the original signal ) my choice will be probably the WavTrigger, for my project I will add a correction filter to compensate the mid/high roll off.

@Robert: can you explain the reason of the roll off in the mid/highs, or is the roll off by design (to get a better SNR)?

And would you be so kind to inform me what the purpose is of the terminals (black square in the picture below)?
As far as I know these terminals are not explained in your product specs and/or manuals.




Greetz Webbie...

[robertsonics]

The design of the WAV Trigger is an attempt to maximize performance while keeping the cost as low as possible. You'll note from the schematic that there is no separate analog supply, although we took great care in isolating the ground and power fills and traces for each section. The only output stage filter on the PCM5100 DAC is the R/C recommended by the data sheet. I was actually extremely pleased by the output quality considering the trade-offs.

Not sure which channel you were measuring, but the LEFT output of the DAC also feeds the AC-coupled input to the on-board LM4990 amp. The PCM5100 is programmed to use it's internal normal FIR interpolation filter, and the de-emphasis control for 44.1KHz is set to ON. I'm guessing it's the effect of the latter option that you're observing.

If you play a WAV file at a gain of 0dB and with no sample-rate offset, you're getting the direct result of sending those 16-bit samples to that DAC with the recommended output filter (on the right channel at least.) There's really nothing else going on that I can think of that would affect the signal. Please compare your results with those shown in the PCM5100 data sheet.

Regarding the additional connectors: One row is simply a convenient place to get GND, 3.3V and 5V, for example if you need to power active sensors, as well as the Play Status output signal (same logic as the Status LED). The other row brings out the I2S signals to allow for connecting a ADC input via an expansion or daughter board. I don't plan to support it, but it would allow someone (or me!) to design an audio input adaptor and write their own firmware to make the board into a stereo-in, stereo-out audio FX unit. Remember that you can use the free Keil ARM-MDK Lite to write and flash your own code using the Firmware Flasher utility.

Hope this helps.

Edit: Turns out that the de-emphasis setting is software controllable. I you'd like to try a version of firmware with this set to OFF, please email me directly at info(at)robertsonics(dot)com.

[Webbie]

Hello Jamie,

Thank you very much for your reply.

I've took the LEFT channel for measuring.
If I have received the other version of your firmware I will take new measurements from both channels and both versions of the firmware.

You've got mail

Greetz Webbie...

[Webbie]

Hello,

Today I've received and tested the firmware version v1.23 of the Wav Trigger with the de-emphasis option switched off.
That did the trick, no roll off more in the mid/highs and sounding now much better, more detail and brighter.

Jamie did a great job on this, so for sure I'm using the Wav Trigger for my project (sending data through sound).

Below the screenshots I took:

LEFT (green) and RIGHT (brown) channel, spectrum analysis with the old Wav Trigger firmware v1.22.


LEFT (green) and RIGHT (brown) channel, spectrum analysis with the new Wav Trigger firmware v1.23.


LEFT channel only, spectrum analysis with the newWav Trigger firmware v1.23.


Legend (from bottom to top):
BROWN = player paused
BLUE = player plays wav-file with "silence"
RED = player plays wav-file with "white noise"
DARK BLUE = player plays wav-file with "pink noise"

Greetz Webbie...