Multiple bundles of fiber-optics, assembled into a propeller driven rotor, gate a beam of infrared light from a photo diode to a photo-sensitive transistor producing electronic pulses.
One of the most reliable water current meter and indicator.
A datalogging version which records depths, width, velocities, angles and features discharge calculation.
to measure flows in faster, deeper water.
to be used while wading in streams, waterways and channels.
for reaching into shallow and partially obstructed man-made channels.