Publisher: ICCRD

Microcontroller-Based Two-Axis Solar Tracking System Lwin Lwin Oo Hardware Technology Department Computer University (Lashio) Myanmar 958-223969 Nang Kaythi Hlaing Hardware Technology Department Computer University (Pinlone) Myanmar 958-130453 ABSTRACT The main goal of this project is to develop and implement a prototype of two-axis solar tracking system based on a PIC microcontroller. The parabolic reflector or parabolic dish is constructed around two feed diameter to capture the sun’s energy. The focus of the parabolic reflector is theoretically calculated down to an infinitesimally small point to get extremely high temperature. This two axis auto-tracking system has also been constructed using PIC 16F84A microcontroller. The assembly programming language is used to interface the PIC with two-axis solar tracking system. The temperature at the focus of the parabolic reflector is measured with temperature probes. This auto-tracking system is controlled with two 12V, 6W DC gear box motors. The five light sensors (LDR) are used to track the sun and to start the operation (Day/Night operation). Time Delays are used for stepping the motor and reaching the original position of the reflector. The two-axis solar tracking system is constructed with both hardware and software implementations. The designs of the gear and the parabolic reflector are carefully considered and precisely calculated. Keywords PIC microcontroller, parabolic reflector, LDR, DC gear box motor, 1. INTRODUCTION Solar energy is the most democratic of renewable energy resources. It is available everywhere on the earth in qualities that vary only modestly. The role of solar energy is indeed going to be predominant. Because solar energy is available free at any place on the earth. Solar energy is renewable and will not deplete within the next several billion years. Several applications of solar energy ranging from simple solar water heating to complex megawatt power generation systems are under extensive investigation. The function of the solar collector is to collect the radiation incident from the sun. Solar collectors can be grouped into two general classifications: flat-plate (low to medium temperature) collectors and focusing (high temperature) collectors. Focusing (parabolic dish) collector systems are the most efficient of all solar technologies, at approximately 25% efficient, compared to around 20% for other solar thermal technologies[7]. Therefore the parabolic reflector is constructed about 2 feet diameter.The two-axis solar tracking system is constructed with two DC gear box motors because the maximum temperature at the focus of the parabolic reflector is always required. This control system is controlled by PIC 16F84A and interfaced with assembly language. 2. PROPOSED DESIGN There are two type of control system, open-loop control system and closed-loop control system.Closed-loop control system is used in this project and PIC16F84A is the main controller and input and output devices are sensors and DC gear box system.The proposed design in this project is as follow: Figure1. Flowchart of the Proposed Design 3. HARDWARE IMPLEMENTATION The procedure for implementing the whole system includes installing the parabolic reflector, choosing suitable design for gear boxes, and assembling the control circuit for the system. 3.1 Making a Parabolic Reflector out of a Flat Sheet The parabolic reflector is constructed with glass fiber plate. The easiest way is to cut and fold a flat sheet into a parabolic dish. Then a layer of glass fire is glued on its inner surface, for reflectivity. The diameter of the parabolic reflector is about 2ft and its radius is about 1ft. So the radii of five concentric circles are drawn with the scales and the circles are divided by 6 uniformly Second International Conference on Computer Research and Development 978-0-7695-4043-6/10 $26.00 © 2010 IEEE DOI 10.1109/ICCRD.2010.59 436