Simple test or demo for audio?

Dan E

Hi, I am trying to write an object that plays a WAV file from a SD card through a speaker attached to an audio power amplifier. As of right now, no sound comes out and I am trying to debug it. My amplifier circuit is pretty simple so I don't think that is the problem, so I figure it must be the pin assignments I used and/or I improperly used the OBEX code.

Is there a simple audio object or demo with pin assignments that could be used to help debug this problem? I would like to see if in fact it is my speaker, power amp circuit, pin assignment, or how I call up the file possibly, and learn how to properly execute this program.

I tried to use the wavePlayerSD and its included objects, although I could not see where I assign the pins I am using, and I am using just one speaker, it seems that that code and others are for 2 speakers.

Thanks,
Dan E

Bill Henning

Here is a quick and dirty audio diagnostic I use for my boards:

' Quick&Dirty Audio diagnostic for PropCade @ Mikronauts.com
pub audio_diag(pin)|f,q
  dira[pin]~~
  repeat f from 0 to 500
    repeat 10
      outa[pin]~~
      repeat f
      outa[pin]~
      repeat f
  repeat f from 500 to 0
    repeat 10
      outa[pin]~~
      repeat f
      outa[pin]~
      repeat f

Rayman

I have a wav player in OBEX that plays an embedded file, so no SD card required...

Dan E

Thanks, I'll try it out.

Cluso99

Dan E: I noticed on the other thread you mentioned it was a 16 ohm speaker amplifier. What you require is an amplifier that works with an iPod equivalent (i.e. takes earphones as inputs). Is this what you have?

Dan E

Yes, it's actually a requires a stereo audio cable, but I cut the cord so that I could wire it to my audio output pin, only to reveal there are 3 wires, red, black and blue.

I assume red is for power, black for ground, leaving blue as the input, but the device already has a 9volt supply, so I'm a little puzzled,

My ipod headphone jack is a little smaller, than this cord, but maybe I can find a better match at radio shack.

Oldbitcollector (Jeff)

Hey Dan,

Just a quick caution. If you are using headphones to the Propeller, do a quick test to make sure that the output is at a safe level for your ears. I've gotten some unregulated audio from my Propeller that really smarted.

OBC

Dan E

Actually, I just checked, and you're right, it is wxactly the same as my ipod headphones, still puzzled as to the correct connection for the 3 wires though.

Dan E

will do, the device I have is a mini amplifier speaker from radioshack, luckily with a volume control.

Dan E

Figured out what the 3 wires were by cutting apart my ipod headphones, and the stereo audio jack.

Although the cable i bought had a jack on each end, the wiring was for a right and left speaker or headphone, which corresponded to the wiring of my ipod headphones, and the other wire was soldered to the isolated ground of the jack.