Acousttic wind speed measurement using phase only

The idea:

formatting link
idea is to simply _add_ direct and reflected signal, use a peak detector.

You do not need the second resistor, there is enough direct coupling between the piezos.

For 1 - 100 km/h wind speed to be in the range -90 degrees to +90 degrees phase shift, the transmitter and receiver must be really close together. few cm actually,. The only way to get the wind to have an unobstructed effect is use reflections.

Test setup (sort of reproduces from a desk full of stuff):

formatting link

I do measure changes, but PC fan is not really that fast, and the blades cause reflections by themselves.

Then as justification not to use it (grapes are too high sort of thing) well pinging, or 40 kHz carrier all the time, is not stealth. LOL

Still waiting for the BMP180 modules... (for differential pressure method).

Using acoustic reflections is not new, others do it too:

formatting link

but look at the price...

Reply to
Jan Panteltje
Loading thread data ...

To take a picture of a piece of paper, set the camera for snow scenes. Then white will come out white. (Cameras assume that all scenes are on average 18% gray, unless told otherwise.)

A one-transistor synchronous detector will do a far better job.

Joe Gwinn

It's weatherproof.

Reply to
Joe Gwinn

On a sunny day (Sat, 13 Jun 2015 11:37:57 -0400) it happened Joe Gwinn wrote in :

mmm

No

Reply to
Jan Panteltje

On a sunny day (Sat, 13 Jun 2015 16:28:13 GMT) it happened Jan Panteltje wrote in :

PS. In the early circuit, in the windtunnel (posted here years ago), I used a dual gate. I disabled that dual gate here because:

1) The amplitude at the tx peize is overa hundred volt pp 2) the amplitude at the rx piezo is hundreds of mV (say 500 mV or so). Adding in the correct ratio gives: 1 V if in phase 0 V if out of phase, 0-1 V DC after the peak detector.

.5 V if no wind.

A huge signal, if into a PIC ADC at 1.0something V reference just right. No gain shit, no power consumption, no distortion.

2 You guys really need to learn how to adjust a monitor.

bet you would wanna change a Rembrand too . ;-)

Reply to
Jan Panteltje

Reason?

Joe Gwinn

Reply to
Joe Gwinn

You might also be interested in this one:

formatting link

Good discussion of some of the technical issues.

--
Regards, 

Adrian Jansen           adrianjansen at internode dot on dot net 
 Click to see the full signature
Reply to
Adrian Jansen

On a sunny day (Mon, 15 Jun 2015 09:21:33 +1000) it happened Adrian Jansen wrote in :

Right, already studied that years ago :-)

And this:

formatting link
formatting link

Reply to
Jan Panteltje

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.