It looks like it is feasible to build an ultrasonic anemometer from cheap commodity ultrasonic transmitters and receivers. Here's a paper on building one from 4

It looks like it is feasible to build an ultrasonic anemometer from cheap commodity ultrasonic transmitters and receivers. Here's a paper on building one from 4 common HC-SR04 ultrasonic modules [1]. The modules are around $2 each on Amazon. One thing I haven't been able to get good information on is what animals think of those. If I were to deploy an anemometer the only good place I've got for it is near a place birds and squirrels like to hang out. I don't want to drive them away, or harm them. I had a similar issue with lasers. I was thinking of deploying a laser distance sensor module to try to detect when something was in front of a wildlife camera. The information from the manufacturer assured me that the laser would not harm a human eye even if the human was staring right at it at close range. But it said nothing about other animals. [1] https://www.e3s-conferences.org/articles/e3sconf/pdf/2020/62/e3sconf_icenis2020_15011.pdf https://www.e3s-conferences.org/articles/e3sconf/pdf/2020/62...