There is a great sonic anemometer in: "An inexpensive sonic anemometer for eddy correlation" G.S.Campbell and M.H.Unsworth, (1979), Journal of Applied Meteorology Vol 18, August 1979, Pp. 1072-1077.
This unit uses 4000 CMOS, a LM301A and two cheap ultrasonic transducers. It operates a phase-locked loop and alternately uses the sensors for transmitter and receiver, swapping ends at about 74 Hz, to get a two way signal. This method cancels most errors. It has temperature and velocity outputs. cheers, Neville Michie On 24/05/2014, at 11:16 AM, Mark Sims wrote: > I am building a weather sensor that includes a ultrasonic anemometer to > measure wind speed, direction, and air temperature. It uses 4 cheap ($1 > each) HC-SR04 ultrasonic rangefinder modules that output a pulse width > proportional to the time of flight of the sound signal (topic is time nut > related since it simultaneously measures the speed of sound in 4 directions > to a pretty good accuracy/resolution using a cheap-ass microprocessor - > ATMEGA328 (like and Arduino)... and does so without using any counter-timer > channels). > Now the question... I would like it to be able to output data in imperial or > metric units. In what units is the typical wind speed reported (meters/sec, > km/hour, ?). Also air pressure (millibars/hectopascals/pascals/?). > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
