January 2006, Issue 186

Internet-Connected Sonic Anemometer

ADDITIONAL IDEAS

As I mentioned earlier, you can extract the Doppler information to compute variations in the wind speed. For most applications, however, it’s enough to take samples and compute a running average and variance to get an idea about the wind’s stability. Because the TOF distance is short and the sensitivity to echoes and reverberation is low, a firing time of 10 ms is easy to achieve. This results in a cycle time of 33 Hz.

My anemometer computes only a two-dimensional wind profile. But by adding an extra transducer to the vertical plane, I can add three more paths to the instrument and measure a three-dimensional wind profile.

Well, this project has been a lot of fun. For my next project, I’ll try to miniaturize the front electronics and attach them to the transducers. I’ll also weatherize the system so I can use it outside for extended periods of time. A friend of mine is interested in placing a stand-alone unit with a GSM modem near his favorite surfing spots in order to obtain wind conditions. Surf’s up!