John-Paul Yaraskavitch, Zoe Ferland, Gavin
Armoogum, and Shanjida Khanam, Mechanical Engineering,
University of Ottawa
In this project we
created a system whereby a solar panel tracks the sun during the
day to maximize the light it receives.Sensors placed on each of the four
corners of the solar panel measure and compare the voltage
received.Changes in the position of the
solar panel are made based on these four inputs.The solar panel will position
itself in such a way that each sensor is receiving maximum
voltage from the sun.
Electrical Materials
-Arduino Uno
Microcontroller
-2 Bipolar
Stepper Motors
-4 Photo
Resistors
-4 46 kOhm
resistors
-2 L293D
H-Bridge Motor Driver Chip
-6 Volt
Lantern Battery
-Soldering
Iron
-Solder
-Wire
Mechanical Materials
-Acrylic
Sheet
-Brass Angle
Brackets
-Nuts and
Bolts
-Hot Glue
Gun
-Wooden
Pulleys
-Elastic
Bands
-Bike Brake
Cable
-Wire Butt
Connector
-Wooden Base
Operation
Each corner of the
solar panel has a light sensor. These light sensors are made
from a voltage divider circuit utilizing a photo resistor and a
normal resistor. The varying voltage of each sensor is fed to
the arduino.The arduino is programmed to
compare the left and right inputs; the output is a stepper motor
which makes changes in the direction of the solar panel based on
the comparative inputs received. This motion is 360° about the
vertical axis.Following the left and right
comparison, the sensor in question is measured with the one
above or below it (depending on its placement on the solar
panel).The output for this comparison on a
stepper motor which moves the solar panel in a 180° arc, the
magnitude of the movement depends on the difference between the
two inputs. The
code continuously reads the voltages and compares and allows the
panel to adjust to any changes. The panel is able to cover a
full hemisphere to mimic the path of the sun and to make changes
if shade should fall on any part of the panel.
Problems
-The motors
initially purchased did not have enough strength to hold/lift
the panel while it was in the downward position. To overcome
this, weight was reduced on the panel by eliminating brackets
and substituting with hot glue. We also reduced the moment arm
of the solar panel by shortening the pieces of plastic to which
it was mounted. We then developed a pulley system using wooden
cut-outs with elastic bands wrapped around each one for
friction. The pulleys are connected with a cable crimped
together with a wiring butt connector.
-Initially
we were using a 9V battery for each motor. This caused the rotor
of the motor to get stuck between two activated coils and stuck
working. We switched to a single 6V battery and the motors
worked fine after that.
Possible Improvements
-
Potentiometers could be added to determine horizontal and
vertical position in order to reset after a day of following the
sun. The coding would have to be added to read the
potentiometers position each morning and move the motors back to
that position in the morning and read the new initial reading of
the sun as it changes with the seasons.
-Stronger
motors in the same compact size could be used to allow the use
of the initial mounting brackets.
-The pivot
holes for the solar panel should be straightened out allowing
for the solar panel to sit square.
-The coding
for the system could be improved to allow all sensors to compare
each other instead of just the top ones for left and right and
the left ones for up and down.
-The wiring
should be cleaned up as sometimes it catches and doesn’t allow
full movement of the panel.
