oscilloscope trigger

[Gavron]

Hi Guys

I am trying to use the sound card as a cheap and nasty oscilloscope. What is the best way to scale a chart or a graph and implement a trigger to get a nice stable waveform? Currently I have combined the two examples, the continuous sound input.vi and generate sound.vi and have got a stereo sound cable connected between the microphone and the headphone jack for testing purposes.

Any help is greatly appreciated.

Cheers

[DFGray]

I would recommend you use a producer/consumer architecture and stream data from your sound card constantly.  Use the Trigger and Gate Express VI to select a subsample of the data stream for triggering (or you can roll your own) and display.  For a full application similar to what you are attempting to write, check out this musical instrument tuner.  Note that the code has a bug.  The buffer size for the acquisition needs to be doubled in the initialization to prevent overflow errors.

[Gavron]

Thanks for your help  I will try and upload my code once I have a simple example working.

Cheers