Daqarta for DOS Contents
OTHER SOUND / EVENT-TRIGGERED OPERATIONS:There is no need to confine sound-triggering to simple data recording. You can use the basic idea of WaitP with Norm triggering to start just about anything, not just processes normally associated with "data acquisition".
For instance, you could set up your computer to create a sound or series of sounds in response to a trigger sound. You might use this for training a bird, or for playing "Hail to the Chief" triggered by a loud throat-clearing. You can create the musical notes from tone bursts on a sound card synthesizer (one tone on each channel), with STIM3A (up to four tones on each channel), or with the PC's built-in speaker by changing the User Tone option.
You could provide a long sequence of digital commands via the digital output option of STIM3A, using programmable WaitS delays between stages, to run a complex industrial process when a measured variable exceeded a threshold.
You don't even need an acquisition board for this, if you use the LPTX driver with your printer port. In the simplest case (with the LPTX DigOut option) you could use a switch closure for the input signal and drive up to 8 different output lines. This only requires wiring things up to a standard DB25 parallel port connector.
There is nothing to prevent macros from changing input channels or trigger levels to do multiple tasks. The LPTX DigOut option, for example, has four digital inputs which could thus allow monitoring four different switch closures. (This option also allows you to combine inputs in a weighted fashion like a 4-bit ADC, so you could have a threshold that represented certain switch combinations.)
You can even use Quit in a macro, so that if Daqarta was invoked by a batch file, the next command after the trigger can be any DOS operation... like dialing your home phone to let you know that an event finally happened and has been safely handled. And with a loop in the batch file you can re-invoke Daqarta after that, and use the !-key auto-initialization macro
The only thing to remember here is that although the time to process macro commands is very fast, it is not instantaneous. While the time to set up a new note to play music in the above example may be imperceptible, there are other cases where every millisecond matters.
For example, you could have a macro that waited for a Norm trigger and then switched the trigger Source from Intern to Pulse and thus generated one or more digital output pulses right after the trigger event. In concept this seems like a good way to trigger a photoflash to capture an exploding balloon. In reality there may be a lag of tens of milliseconds to change modes, plus fill the sample queue on a typical sound card, so you might miss the desired shot.
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