  Disdrometers detects size and speed of falling rain droplets in a rainfall.
They detect droplets either by impact or optical based methods. Optical based
ones, use light source and an optical detector. Droplet crossing the light
creates shadow on the detector. This change in the intensity and duration of
change provides the size and speed of the droplet. Whereas the impact based
method utilizes peizo elements to sense the droplet by physical momentum
transfer at the time of droplets impact with the sensor. Apart from the
technical differences in them, both of these disdrometers fall in the similar
cost range. Wind turbulence sensors works on detection of gradients in wind
speeds by employing various working principles like thermal anemometer, laser
Doppler anemometer, etc. In thermo anemometers, a heating element is maintained
at a constant temperature. As the wind flows, it carries some heat energy away
from the element. This causes a change in the resistance in the heating element
providing further change in voltages across it. Laser Doppler anemometers work
on change in wavelength of light scattered by a moving particle which is caught
in the wind flow. These techniques are highly accurate in measuring the
turbulence in the air but at elevated costs. Aimed at cost efficacy and
acceptable performance of the device, a novel concept was implemented in a
single device to study its feasibility to work as a disdrometer and a
turbulence sensor. It employs the principles of electromagnetic induction and
response of a cantilever to impulses. Based on these principles, a device was
designed and fabricated to detect rain droplet size and wind turbulence. It was
fabricated from readily available materials. The testing of the device in
laboratory conditions yielded satisfactory results as compare to the standard
commercial instruments.
