In this semi-spherical meter, a single detector is used to realize all measurements, which is located on the extreme of a
rectangular ring (assumed as joined two mobile branches in order to compensate the weights), describing half-meridians
from 0° up to 170°. The illumination source under test is located at the center of the mobile support, which can rotate
360° horizontally. The two combined movements allow us to obtain a semi-spherical geometry. The number of
measurement points is determined by the two step-motors located under the mobile support of the luminary and on one
of the two fixed arms, which support the mobile rectangular ring, respectively.
The mechanical arrangement has the enough rigidity to support the precision required for the acquisition stage, based on
a dsPIC. The main advantages of this arrange are: Its low costs (using recyclable materials only such as "electronic
waste"), a reliable detection based on a single photo-detector, with an integrated amplification stage, and the mechanical
The received power by the detector is useful to obtain the irradiance profile of the lighting sources under test. The semi-spherical
geometry of the meter makes it useful for the analysis of directive and non directive sources, in accordance
with the angle described by the mobile ring. In this work, special attention is given to LED lamps due to its impact in
several sceneries of the daily life. A comparison between the irradiance patterns of two LED lamps is also given.