Tracking is a fast growing area for research,industrial and engineering applications.Automatic Tracking Systems and their place in various applications like exploration ,industrial automation,navigation,safety enhancements and entertainments. Sun Tracking Systems can be developed to function as an aid in exploration endeavors,missions to areas inaccessible to human beings,and much more. It is a mechanism which tracks the sun throughout the day,thus optimizing the conversion of solar energy to optimal energy.As the sun rises from the east and goes down in the west,the panels adjust accordingly to increase the efficiency of the solar panels. The single access tracking system is the simplest solution and the most common one used. Once the sun tracker system is turned on,it follows the sun generating highest light intensity in that region and constantly moves towards the location receiving the highest light intensity.
The system is based on PIC16F877A microcontroller.The Code for the functioning of this system is stored in its 8K flash program memory.
Drive Mechanism and Body
Two motorized wheels driven by DC motor are used to drive the system.The entire body is made up of low weight aluminum sheets,folded and riveted into the desired shape.
The code for the functioning of this system is written in C and is compiled using MikroC Compiler for PIC .The corresponding HEX code generated is burnt into the Microcontroller's memory using JDM programmer.
The sun tracker system has mainly 4LDRs, a microcontroller part and two DC motors for tracking. The four LDR’s outputs are connected to the microcontroller. The two LDR’s will control the rotation of solar panel in one plane,and the other two LDR’s will control the rotation of panel in the perpendicular plane. The predefined program of the microcontroller for rotating the DC motors in the required direction will provide the input to the DC motor driver according to the LDR’s outputs. Considering the LDR’s ,placed 180 degree apart, if any one of the two LDR’s is active ,then according to the predefined program one of the DC motor rotates either in clock wise direction or in anti clockwise direction.
Light Dependent Resistor (LDR)
A photoresistor or Light Dependent Resistor is an electronic component whose resistance decreases with increasing light intensity.It can also be referred to as a photoconductor. It is made of a high resistance semiconductor. If light falling on the device is of high frequency,photons absorbed by the semiconductor and electrons jump into conduction band. The resulting free electron(and hole)conduct electricity,thereby lowering the resistance.
Peripheral Interface Controller
The PIC used here is a 40 pin PDIP and has an operating speed of 20MHz. It is a high performance RISC CPU. It is an 8-bit micro controller with an instruction set of 35 single word instructions. Contains 2 comparators, 6 channels of 10 bit A/D converters,a synchronous serial port,a USART, a parallel slave port and some other features controller with an instruction set of 35 single word instructions.
Special micro controller features includes,
- Flash memory:14.3 Kbytes (8192 words)
- Data EEPROM: 256 bytes Self reprogrammable under software control
- In circuit serial programming power saving sleep mode
- Analog features 10 bit 8 channel, A/D converter Analog comparator module
- Comparator outputs are externally accessible
Peripheral features are
- 33 I/O pins,5 I/O ports
- Timer 0: 8-bit timer/counter with 8-bit prescaler
- Timer 1: 16-bit timer/counter with prescaler
- Timer 2: 8-bit timer/counter with 8-bit period register,prescaler and postscaler
- Two Capture(16-bit), Compare(16-bit), PWM (10-bit) modules
- Synchronous Serial Port with two modes (SPI Master, I2C Master and Slave)