I've got a good start from these sites.http://trekker.customer.netspace.net.au/wind.htmhttp://www.circuitcellar.com/library/print/0106/Cyliax-186/index.htmhttp://www.technik.ba-ravensburg.de/~lau/ultrasonic-anemometer.html
My hardware is up and working fine.
You need to use zero crossing detector with a good low noise amp.
This is from the ravensburg site which describes how you
can get the accuracy you require:
I'm able to get the phase shift to give me a accurate
wind speed up to +- 8 microsec(+- 60 deg) phase difference.
That is from 0 to about 10 kph.
If you exceed this speed the phase shift moves on to the next
pulse(each is 25 microsec).
Here I come unstuck. The poor little starfish brain freezes up.
I cannot see how to determine if we have moved on to the next pulse.
What I would like is to see some software that is actually working.
The sites I have conviently leave out their software.
They leave hints like:
It was very hard work to develop this program.
In the present state it can not be used directly with other mechanics.
This will cause erratic readings and needs to be compensated for in software.
I have done an extensive google search but cant find any