embedded solar tracking instrumentation system

Abstract—This paper describes the embedded solar tracking

instrumentation system by using Atmega32 microcontroller. The

system consists of Light Dependent Resistor (LDR) sensor, DC

motor and Xbee wireless system. Atmega32 microcontroller is the

main component for controlling the system. The solar system will

track the location of the sun to ensure the solar panel is always

perpendicular with the sun therefore optimizing power output.

The operation of the system on sunny and bad weather condition

has been presented in this paper. The solar tracking prototype

has been stated for future works.

Index Terms–Embedded, Microcontroller, Wireless, Solar

panel, Solar tracking

I. INTRODUCTION

he global warming crisis , which is mainly caused by

carbon emission is an issue of alarming concern.

Immediate, effective and practical actions to eradicate the

problem should be taken before it worsens. The emission of

carbon as a by-product of electric generation from fossil fuels

impacts lives and the Mother Nature. Renewable energy such

as solar energy provides a sustainable, safer and much

healthier power production, in return safeguarding the earth

from the dangers of pollution. To date, solar energy is the best

way to replace fossil fuels as the main source for generating

electricity.

Solar energy uses sun rays that is an unlimited source and

available for a long term with zero pollution by-product

compared to fossil fuels [1-5]. Besides, the solar energy source

is free while the price of fossil fuels had tripled for the last 15

years [3].

The limitation on existing solar energy system is the system

is not efficient as it generates low power output and demands

high cost. This can be solved by developing an embedded

system based on Atmega32 microcontroller and by adding

Xbee wireless system for collecting and monitoring data.

Nowadays, Atmega32 microcontroller and Xbee wireless

system are widely used in the development of an embedded

system in many areas. It is because of the reasonable cost,

simplicity and ability to connect with a large number of

devices [6]. Both Atmega32 and Xbee are easy to install and

can be used in any situation.

This work was supported by the Ministry of Higher Education (MOHE)

and UniversitiTeknologi Malaysia.

II. SOLAR ENERGY TECHNOLOGY

The enhancement of solar energy system has grown from

fixed mounted to tracking instrumentation solar panel system

and flat to parabolic dish solar panel. The early solar energy

technology is based on fixed mounted solar system. The

tracking system is added in order to improve the efficiency of

the existing system. The purpose of the tracking system is to

overcome the limitation of fixed solar panel mountings

system.

The shading effect is considered in tracking the location of

the sun. The sunlight was diffused through the interaction of

clouds and dusts [1] [7]. The purpose of parabolic dish solar

system is to ensure the sunlight can be focused at one point

and it can increase the efficiency of the solar energy system.

The improvement of the solar energy system by implementing

the tracking system and parabolic dish will gain maximum

power output due to the alignment of solar panels towards the

sun.

The most important aspect in the tracking instrumentation

system is to track the location of the sun. The location of the

sun depends on the latitude of the site and according to the

times of the years [1]. Based on the location of the sun as

desired orientation, the tracking device will trigger the motor

to operate the solar energy system. The tracking device is used

in order to ensure the panel is aligned with the sun. Hence, the

maximum output power gain can be achieved.

Solar tracking instrumentation is a closed-loop function

system. A closed-loop function system is known as feedback

system. Feedback system is needed to ensure the solar panel

always perpendicular with the sun. Fig. 1 shows the block

diagram of solar tracking system.

Location of the sun is set as desired input of the system.

The sensor is used as the tracking system. The subject of

orientation for the system is a condition of the sunlight. It can

be either east or west and north or south. Measuring device

that used as feedback system is the movement of the motor.

Finally, the sun is perpendicular with the solar panel.

Fig. 1: Block diagram of the solar tracking instrumentation system

Embedded Solar Tracking Instrumentation

System A.H. Yamin, M. N. Ibrahim, M. Idroas and A.R. Zin

UniversitiTeknologi Malaysia

81310 UTM Johor Bahru, Malaysia

T

978-1-4673-5074-7/13/$31.00 ©2013 IEEE

2013 IEEE 7th International Power Engineering and Optimization Conference (PEOCO2013), Langkawi, Malaysia. 3-4 June2013

223

III. SOLAR TRACKING INSTRUMENTATION SYSTEM

The overall solar tracking system is shown in Fig. 2. The

main control system for the solar tracking system is Atmega32

microcontroller. By implementing Atmega32 microcontroller

in this project, the microcontroller is used to control the

process flow and data transfer and stored the data for further

use.

The Light Dependent Resistor (LDR) sensor is used and it

was attached to the dish parabolic concentrator to ensure the

system is always perpendicular with the sun. The sensor will

detect the sunlight and transmit the signal to Atmega32

microcontroller. Then, the microcontroller will trigger the

motor to move accordingly. The detection of the sun is based

on the signal received from the sensor to make sure the panel

is always perpendicular with the sun.

At the same time, the data received from the sensor will be

stored in Atmega32 microcontroller. The information stored in

Atmega32 microcontroller will then be sent to the computer

by using Xbee wireless system to be analyzed and saved.

The sunlight will strike the surface of the dish parabolic

reflector. Then, the sunlight is reflected to the solar panel that

is placed at the focal length of the dish parabolic system. The

light energy will be converted into electrical energy when the

light strikes the solar panel. The output from the solar system

is Direct Current (DC) which can be stored to the battery or

converted to the Alternating Current (AC).

The circuit for all solar energy system is designed by using

Proteus software. The circuit is separately designed and

consists of:

• Atmega32 microcontroller

• Light dependent resistor (LDR) sensor

• DC motor

• XBEE wireless

Fig. 2: Overall solar tracking system

A. Atmega32 microcontroller

Atmega32 microcontroller is the main part of the system.

Atmega32 microcontroller is a high performance with low

power microcontroller. The operating voltage for Atmega32

microcontroller is 5V. The speed grades of Atmega32

microcontroller is up to 16MHz [8]. The Atmega32

microcontroller is used for comparing the external comparator

output, controlling motor movement for the dual-axis system

and to control the Xbee wireless system. Fig. 3 shows the

photograph of Atmega32 microcontroller.

Fig. 3: Atemega32 microcontroller

Atmega32 microcontroller has 40 pins and every pin has

their own functions. Some of the features used in this project

are programmable I/O line, 8-channel 10-bit analog to digital

converter (ADC) at PORTA and universal synchronous

asynchronous receiver transmitter at PORTD (Pin 14 and Pin

15). Fig. 4 shows the pin configuration for Atmega32

microcontroller.

Fig. 4: Atmega32 layout

B. Light Independent Resistor (LDR) sensor

By implementing the tracking system in solar energy

system, the location of the sun can be determined. The system

tracks the sun based on light intensity of the sunlight. In this

project, light dependent resistor (LDR) is used as the

sensoring device to detect the sunlight. Five LDR sensors are

installed in the system.

One of the sensors is used as a switch for the system. When

this sensor detects sunlight, the system will be enabled. Two

other sensors are used to detect the sunlight either north or

south along azimuth motion of the system while another two

sensors are used to detect the sunlight either east or west along

altitude motion of the system.

In this project, three comparators have been installed. Each

comparator is used to compare the value of two sensors. The

value of the sensor is based on the presence of the sunlight.


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The comparator is connected to Atmega32 microcontroller as

the input for the tracking system.

Furthermore, four LEDs are also used in the system as the

indicator for the movement of the motor. For example, two

sensors are placed at left and right of the parabolic dish. When

the system detects the presence of the sunlight, all the LEDs

are switched on. When one side of the sensor is gain more

sunlight, one of the LED will be switched on and the DC

motor will move anti-clockwise and vice versa. Fig. 5 shows

the connection of the sensor.

Fig. 5: Connection of the sensor

C. DC Motor

Two DC motor are required in the solar tracking

instrumentation system. The first motor is used to move along

azimuth motion which is either north or south. Another motor

is used to move along altitude motion which is either east or

west.

Motor driver is required to drive the motor. The motor

driver is connected between Atmega32 microcontroller and

DC motor. The 12V DC supply does not give enough torque

to move the motor. The power amplifier circuit is needed in

order to give enough torque to move the motor. So, Darlington

pair circuit is placed in between the motor driver and DC

motor [9]. Fig. 6 shows the connection between Atmega32,

motor driver and DC motor.

Fig. 6: connection between Atmega32, motor driver and DC motor

D. XBEE Wireless System

Most developers of solar tracking system are not really

concerned on collecting the data. There is not much work done

on applying wireless network system to collect the data real-

time [10] [6]. The data received from the solar tracking system

are monitored manually at site. Sometimes, it is hard to collect

the data during a bad weather.

In this project, Xbee wireless system will be used to collect

the data based on real-time. These days, Xbee wireless system

is widely used for data transferring. By using XBEE wireless

system, data monitoring becomes easier. Besides, it is cheap

and compatible to use in most situation. Fig. 7 shows the Xbee

wireless system module.

Fig. 7: Xbee wireless module

The Xbee wireless system has low data transfer rate which

is 250kb/s and it has low power consumption [11-14]. The

input voltage to the Xbee wireless system is 3.3V. The

distance range for indoor is up to 30 meter while for outdoor,

it is up to 100 meter [10]. The Xbee wireless system is based

on 802.15.4 IEEE standard protocols [12]. Fig. 8 shows the

connection of Xbee wireless system.

Fig. 8: Connection of Xbee wireless system

IV. OPERATION OF SOLAR TRACKING SYSTEM

Basically, the sensors can detect the exact location of the

sun with the presence of sunlight. However, the weather

conditions are not sunny all the time. Therefore, the operation

of solar tracking system should include the bad weather

condition too such as cloudy day and rainy day. The operation

is based on presence of the sun throughout the year. The

operational flow chart is shown in Fig. 9. This project

provides two ways of operation and control mechanism which

are:

• Normal sunny condition

• Bad weather condition

The presence of the sun can be identified by knowing the

latitude and longitude of the site. The latitude and longitude of

Malaysia is +3.16 (3º09º36º N) and +101.71 (101º42º36º E)

[15]. So, the sunrise is about 7 a.m. while the dawn about 7

p.m. In this project, the system will be started an hour after the

sunrise which is 8 a.m. The system will be stopped an hour

before dawn which is 6 p.m. Fig. 10 shows the time of sunrise

and dawn in Malaysia.

A. Normal Sunny Condition

Four sensors are used to detect the presence of the sunlight.

The output voltages from two sensors that represent east/west

and north/south are compared. The east sensor is compared

with the west sensor and the north sensor is compared to the

south sensor. Based on the result obtained from the sensor, the

solar panel will track the sun.


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B. Bad Weather Condition

On bad weather day, the sensor cannot detect the presence

of the sunlight because of the interaction of clouds and dusts.

The sunlight that strikes the system will lessen and insufficient

voltages will be received by the sensor. It can be difficult to

the sensor to determine the exact location of the sun. The

problem can be solved by implementing the algorithm for the

movement of the solar panel. The rotation of the earth towards

the sun is 360º in 24 hours. Every hour, the earth rotate about

(360º/24=) 15º. So, to collect data every 15 minutes, the

rotation of the earth towards the sun is about 3.75º [7].

Fig. 9: Flow chart of the solar tracking system

Fig. 10: Sunrise and dawn in Malaysia [15]

V. PRELIMINARY RESULT

The simulation test has been conducted to verify the

interaction between light sensor and motor. Fig. 11 shows the

circuit of the interaction between light sensor and motor. This

circuit consists of two light sensors to detect the light, two

motors and two LED as indicator. The motor rotates either

clockwise or anti-clockwise when the sensors detect the

presence of the light.

Fig. 11: Interaction between light sensor and motor circuit

VI. DESIGN OF SOLAR TRACKING SYSTEM

The development of the overall solar tracking system has

two stages and it is done separately. The first stage is

developing a software system that focuses on the operation of

the solar embedded system. Meanwhile, the second stage is

developing a hardware system which consists of developing

on the prototype of solar tracking instrumentation system. Fig.

12 shows the prototype of solar tracking instrumentation

system. The prototype is built using polyvinyl chloride (PVC)

material because of low cost, flexibility and durability for

higher temperature. The idea of prototype platform is based on

tripod due to stability of the system. Roller is installed to

move easily from one location to others.

Fig. 12: Prototype of solar tracking instrumentation system.


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The construction of the prototype will be done based on the

operation of the solar that had been developed on software

stage. The design of the prototype consists of four sensors that

are placed on the north, south, east and west of the parabolic

dish. The installation of the sensor is sufficient enough to

detect the exact location of the sun and to ensure the solar

panel is always facing towards the sun.

The system used parabolic dish to reflect the sunlight. Small

solar panel is placed at the focal length of the parabolic dish.

As a result, the sunlight will be reflected and focused on the

solar panel hence maximizing the power output gained. Fig.

13 shows parabolic dish reflector that can be used for

developing the prototype of solar tracking system.

Fig. 13: Parabolic dish reflector

VII. CONCLUSIONS

The paper has presented a method of embedded solar

tracking instrumentation system by implementing Atmega32

microcontroller. A solution to maximize the solar panel output

is done by positioning the solar panel towards the sun to gain

maximum light intensity. A method for tracking the sun on

sunny and bad weather condition is also discussed in this

paper. The systems also provide more convenient ways on

data collection by implementing Xbee wireless system.

REFERENCES

[1] LYNN, P. A. 2011. Electricity from Sunlight: An Introduction to Photovoltaics, John Wiley & Sons.

[2] HOSSAIN, E., MUHIDA, R. & ALI, A. Year. Efficiency improvement of solar cell using compound parabolic concentrator and sun tracking

system. In: Electric Power Conference, 2008. EPEC 2008. IEEE

Canada, 6-7 Oct. 2008 2008. 1-8. [3] ALEXANDRU, C. & POZNA, C. Year. Virtual prototype of a dual-axis

tracking system used for photovoltaic panels. In: Industrial Electronics,

2008. ISIE 2008. IEEE International Symposium on, June 30 2008-July 2 2008 2008. 1598-1603.

[4] ZHOU, Y. & ZHU, J. Year. Application of Fuzzy Logic Control

Approach in a Microcontroller-Based Sun Tracking System. In: Information Engineering (ICIE), 2010 WASE International Conference

on, 14-15 Aug. 2010 2010. 161-164.

[5] KASSEM, A. & HAMAD, M. Year. A microcontroller-based multi-function solar tracking system. In: Systems Conference (SysCon), 2011

IEEE International, 4-7 April 2011 2011. 13-16.

[6] Kioumars, A. H. and T. Liqiong (2011). ATmega and XBee-based wireless sensing. 5th International Conference on Automation, Robotics

and Applications (ICARA), 2011.

[7] KHAN, M. T. A., TANZIL, S. M. S., RAHMAN, R. & ALAM, S. M. S.

Year. Design and construction of an automatic solar tracking system. In: Electrical and Computer Engineering (ICECE), 2010 International

Conference on, 18-20 Dec. 2010 2010. 326-329.

[8] http://www.atmel.com/Images/doc2503.pdf [9] LWIN LWIN, O. & HLAING, N. K. Year. Microcontroller-Based Two-

Axis Solar Tracking System. In: Computer Research and Development,

2010 Second International Conference on, 7-10 May 2010 2010. 436-440.

[10] Zulkifli, N. S. A., F. K. C. Harun, et al. (2012). XBee wireless sensor

networks for Heart Rate Monitoring in sport training. International Conference on Biomedical Engineering (ICoBE), 2012.

[11] http://www.digi.com/pdf/ds_xbeezbmodules.pdf

[12] Benkic, K., P. Planinsic, et al. (2007). Custom wireless sensor network based on ZigBee. ELMAR, 2007.

[13] Ping, W. (2008). The Real-Time Monitoring System for In-Patient

Based on Zigbee. Second International Symposium on Intelligent Information Technology Application, IITA 2008.

[14] SeongPeng, L. and Y. Gik Hong (2011). Centralised Smart Home

Control System via XBee transceivers. IEEE Colloquium on Humanities, Science and Engineering (CHUSER), 2011.

[15] http://www.gaisma.com/en/location/kuala-lumpur.htm


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