Leaf area is an important index in plant growth study and in
prediction of the product of crop. Various methods as square
grid counting and gravimetric and pixel counting using image
processing are mostly used for leaf area measurements. On
the other hand, when dealing with a large number of leaves
these approaches turn out to be laborious and time consuming.
A solar cell based method for leaf area measurement was
developed and implemented. In this system, the shadowing
effect by the plant leaf on the solar cell was used. The system
has two 7 ∗ 10 cm2 and 5∗7 cm2 amorphous silicon solar
modules which were composed of 6 series connected cells, an
11 W PL lamp, a stainless steel parabolic reflector for reflecting
the light from the light source to the solar module in parallel,
an opal glass used for diffusing the parallel reflected light,
and a case for housing these components. Different geometric
shaped areas were used to simulate the leaves having various
shapes. The current and voltage values were measured due
to shadowing effect of these areas to be evaluated. The
resulting voltage and current measurements were then fed to
an ARM Cortex M3 core 32-bit LM3S1968 microcontroller
via a voltage and current measuring unit. The calculated leaf
areas from the obtained area-current relations were shown on
an OLED graphics display. The whole system is easy to use
and user-friendly.The achieved results are compared with the
measured areas by grid counting method. Different species of
leaves are tested by the leaf area meter. Experimental results
show that this developed method contributes to a result that
is reasonable to be used as a leaf area meter. Accuracy of this
method is found to be about ±99% for regular shaped leaves
where accuracy is ±95% for irregularly shaped leaves.The leaf
area measurements are confirmed by comparing the results
with measurements of grid counting method