Time-stamping and Discretising Audio Signals into Raw Data

[scottyheist]

I'm logging the RPM of a scaled wind turbine using a laser and modified microphone (with a photocell instead of a coil).

The signal is recorded using Audacity and is a series of troughs separated by the time it takes for one blade to pass through the beam (please see attached image below).

Is there a way to convert this signal into an array of time-stamps and signal strengths (0.0 to 1.0)?

I aim to eventually have a time vs. instantaneous RPM plot.

[ranger]

Does Audacity support exporting your data into a csv style or similar format? What is the worst case value you might expect for RPM?

Are you able to interface to some signal conditioning circuit and then a uC? Maybe you want to leave the uC out of the picture and do some low level programming and interface your signal conditioning circuit to a port (serial/parallel) via an ADC?

[scottyheist]

Thanks for your response. We're now pursuing your method.

Would you have any advice on the ADC/computer interface?