A portable integrating omnidirectional anemometer

A portable lightweight instrument developed to investigate the effect of total wind flow on plant growth is described. The sensing device is a directly-heated thermistor bead. From the cooling effect of the wind on the bead the electronic circuits produce a voltage that varies linearly with respect to speed over the range of 1¿30 miles/hour. This voltage is integrated by a d.c. motor with an attached revolution counter to give the wind flow over a time determined by the operator. The reading is sufficiently independent of direction to be useful in the intended application.