# Measuring Wind Speed Using Ultrasound Transmitter and Receiver

I am currently trying to create an system to measure wind speed, and I know ultrasound is a good way to do it. I want to make my system be lower cost, however, still maintaining 0.5 m/s precision or better.

There are a few ways I thought to do this.

1. Measure time of flight into the wind and time of flight with the wind, and calculate the difference to get wind speed.
2. Measure the shift in phase from the emitted signal to the received signal
3. Use an ultrasound transducer array to determine how much the transimtted sound wave has shifted due to the wind (system oreinted perpendicular to the wind)
4. Measuring intensity of sound with and against the wind.

For method 1, I think I could disassemble and HC-SR04, placing the transducer opposite the emitter. Then I could measure time of flight without reflections. However, the precision is not quite good enough. I want something ~0.5m/s, and it seems like this method will give me ~5m/s. I am wondering if there is a way to improve the precision of this device. Or perhaps there is another device, or other pieces I could use to build my own more accurate version.

For method 2, I'm not sure what electronics I would need to use measure the phase difference. Is there a simply way to measure the phase difference between the output signal and the received signal?

For method 3, I could not find any sensors that are low cost.

For method 4, I believe it should be a 1/r^2 decay, but this may not be a precise enough method.

Please let me know if you have any insight on which methods would work best and how to implement these. Perhaps I would need a combination. I thought about using time of flight to get a coarse measurement and phase shift to refine the measurement

Thanks for the help!

Alex

• Have you considered hot wire anermometers? Sep 13, 2016 at 19:49
• or a simple cup anemometer or a pitot tube or a heated sonic anemometer - you seem to be jumping to what is a very complex (and expensive) solution. KISS Sep 13, 2016 at 19:56
• Thanks for the comments. I have looked at the other options. I will likely use a Pitot tube, but I wanted to explore other options first. There are other advantages to the ultrasound meansurements too. For the hot wire anemometer, there was a reason a ruled it out, power consumption comes to mind, but Ill have to look back at my notes. Sep 13, 2016 at 20:12
• So in some sense, my question is also "Does an ultrasonic anemometer have to be expensive?" Sep 13, 2016 at 20:14
• Should be doable "on the cheap" but how much work is involved is tbd. || "For fun" if not already seen look at "von Karman vortex" and "von Karman vortex street" in the context of velocity measurement. || Maybe start here ... Sep 14, 2016 at 1:49

Alex, For #1, there is a very good description of a project there: ultrasound anemometer

You can definitely find cheap components to implement your project. Microcontrollers are plentiful and cheap. If you look for ultrasonic transducers, they are cheap too.

• Any ideas on where to buy transducers. It seems like ebay has good deals, but I am not sure about the quality there. Dec 28, 2016 at 5:28
• Alex, try alibaba, I've never used it though. Let me know your experience. For instance: alibaba.com/product-detail/… Dec 30, 2016 at 20:12