[simpits-tech] RE: [simpits-tech]Sound Card for analog I/O

[Craig Rochester]

In my quest for cheap analog I/O, I've been trying to use a 2nd(3rd.....)
sound card(s) for a poor man's high resolution, good bandwidth A/D and D/A
converter.

I wrote a bit about it on my webpage:
http://pages.zdnet.com/johncraigrochester/vrvision/id12.html

I use a C++ program( that came with the DX8 SDK) to send a sine wave signal
to the sound card.  I amplify the signal coming out the sound card with an
old stereo tuner/amp.  The amplified signal goes through a "full wave bridge
rectifier"(DC converter minus the transformer) to convert the AC output to
DC.  I can then use the volume adjustment to send a 0-9 VDC signal out.

I've used the circuit to drive a pneumatic pressure device (I/V).  I'd like
to interface this to Falcon4 via the shared MMF, I'm stuck at trying to
figure out how to do the coding.  It's beyond my meager programming
abilities to initialize a second sound card, open a channel, start the sine
wave, and then adjust the volume proportional to the G variable in the MMF.

I'm not sure I'm understanding the SoundBlaster specs right.   I read: 4 D/A
output channels with 16bit frequencies can easily in the kHz range.  I
haven't tried it yet, but the input channels could be used for analog
inputs.

I'd appreciate any advice from a coder, particularly if there's something
I'm missing that will prevent this from working.

BTW, I did hook the pneumatic rig up to the sound output from Falcon4.  It
felt pretty interesting, like a big speaker without the sound. :)

Craig R.