I am trying to set up a crude sound card means of datalogging the zero crossing times for a (somewhat) changing frequency sine (somewhat) wave. I have a homebrew voltage to frequency converter that puts out a sinewave, around 2 volts peak to peak. The input to the voltage to frequency to voltage converter is the analog signal I am trying to plot. It is a slow moving signal that is an output of a sensor. So, when the sensor input increases and decreases in amplitude, the voltage to frequency converter changes frequency.
My overall project is to find a very fast ‘wakeup’ sensor that can sit idle drawing nearly zero battery power, then wake the mouse when the sensor determines the mouse has moved. In this manner, a high power gaming mouse can be used without sucking up battery power when the mouse is not being used.
I would like to have the length of time between each zero crossing of the analog output of the voltage to frequency converter, in a text file if possible. Technically, I’d like to plot the delta T of each successive zero crossing, but if I can get the raw data containing only the zero crossing time, I can handle the plotting.
I can recover the raw data of the sensor output by using Analyze>Sample Data Export. But, I might be able to enter the raw data into a spreadsheet and find each zero crossing manually, but with 30 seconds of data at 44 Khz, it would take forever to manually recover all the zero crossing times.
I know I can use Analyze>Silence Finder, but it only gives me a graphical representation of multiple zero crossings without the exact time that a zero crossing happens.
I’m good with analog hardware, but not so good with software/digital.
I have no fancy hardware, an old core duo processor in an HP laptop using the onboard sound card. And, I do not need extreme precision or a fast sampling rate (8 KHz sampling is more than adequate because these are not fast sensors).
Is there anyway that Audacity can output the change in period for each zero crossing and plot it or give me a text file output showing the duration between each zero crossing event? I can handle fabrication of hardware if needed, but my budget is low and I am hoping the sound card/Audacity can handle the task without additional hardware.