ABSTRACT. Keywords: Solar Panel, Charger controller, PIC Microcontroller, Proximity sensor Mobile device. I INTRODUCTION II HARDWARE REQUIREMENTS

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1 Dual Mode Charging With Control System for Mobile Devices Chandini H.V, Nischal R Gowda, Rakshitha N, Shwetha M.S VIII Semester, BE Students, Department of Electronics and Communication Engineering Bahubali College of Engineering, Shravanabelegola, India chandinihv2@gmail.com, nischalgowda33@gmail.com, rakshithan7@gmail.com, shwethashankar396@gmail.com ABSTRACT Today s smart phones are providing many features, at the same time they cannot keep up with battery demands. So in this paper, we design, construct an electronic circuit to charge mobile phones using solar energy as a source of power. Solar chargers are simple, portable and ready to use in remote areas where there is scarcity of electricity and also mobile can charge using electric power with available electric socket. Charge controlling is accomplished using FM63160FE. The PIC microcontroller controls the overcharging and deep discharging of battery and output voltage is displayed on LCD, then designing of a control system that can avoid the explosion of a mobile battery. Keywords: Solar Panel, Charger controller, PIC Microcontroller, Proximity sensor Mobile device. I INTRODUCTION Technology has allowed the cellular phone to shrink not only the size of the ICs, but also the batteries. However, as technology has advanced and made our phone smaller and easier to use, we still have one of the original problems that we must plug the phones into electric socket to recharge the battery. Most people accept the reality as there is no other option to this problem so they carry extra batteries with them. Every time it is not possible to charge mobile batteries everywhere at any time. So we designed the solar mobile charger from which we can charge the mobile battery anywhere at any time. We have enormous nonconventional energy sources but the usage of renewable energy is not to its fullest extent. Generally wind, hydro, solar, tidal are different forms of nonconventional energies. In this project we are using the concept of energy harvesting by solar energy for battery charging purpose, because solar energy is renewable energy, portable and it available everywhere. Using this we can charge our mobile battery in remote areas where there is a problem of electricity and system design include one charge control circuitry that prevent the battery from overcharging and deep discharging. Cost of this circuitry can be reduced, if manufacture implements circuit. The rest of the paper is organized as follows: section II presents an overview of hardware requirements, section III gives an overview of software requirements, section IV presents methodology, section V gives implementation of the system and section VI describes applications, section VII gives advantages and section VIII presents conclusion. A. Solar Panel II HARDWARE REQUIREMENTS There are two basic types of solar panels, first one is the crystalline solar panels made of crystalline silicon and other is amorphous silicon panel which is made from amorphous silicon. In order to make Crystalline solar panels, thin disks are cut from silicon in its crystalline form which are 8 cm thick. These disks are then subjected to a careful polishing and repairing process to ensure that no damage occurred during the cutting process has remained unattended. The thickness of these disks is so less that they appear to be wafer like disks which gives them the name silicon wafers. Now for the main part of the process, adding the Dopants. Dopants are materials that are added to these silicon wafer disks so that they get electrically charged. The positive and the negative charges are added accordingly in these silicon disks and then are joined together so that electrons when subjected to sunlight can flow

2 and conduct electricity. These disks now with the dopants in that are aligned horizontal and vertical manner to form a matrix pattern forming a solar panel. These solar panels are then covered with plastic plate in order to protect them from any physical damage or scratches reduced the weight of circuit. From the solar energy the panels receive two types of energies light and heat energy. These solar panels are then fitted with a special type of cement. This is conductive cement which transfers the thermal energy from the solar panels. The amorphous silicon solar panels are made quite differently. Fig.1: Crystalline Solar Panel The manufacturing process of amorphous silicon panels involves depositing silicon alloys in various layers. The solar cells made by this process are far more efficient and are capable of absorbing a wider range of solar spectrum. This type of panel manufacturing is now becoming very popular and is fast growing into an industry. The material cost of such solar panel is also cheap. B. Charge Control Circuit FM6316FE is applied to a mobile to charge integrated lithium battery, DC-DC step-up and load detection.icfm6316fe, which include trickle charge, constant current and constant voltage charging of the battery and also it shows charging process. Charging status indicator lamp is also used. Charge current is programmed by an external resistor. When the external input power is removed, it will shut down the system. If the external device is not detected the access the system enters the standby state, the standby current of the entire system 16Ua. FM63160FE has multiple protection design, which including charging anti-intrusion protection, soft start, over-temperature and under voltage protection. B,1. Characteristics External circuit is simple. Built-in rechargeable turn lights function. Load detection shutdown. Standby current 16uA. Trickle / constant current / constant voltage three-stage charging. IC boost efficiency up to 90%. Constant charging current value can be externally programmed. Package: ESOP-8.

3 Fig 2: Control Circuit B,2. Applications Mobile power. IPAD and other digital equipment standby power. C.LCD Display LCD display for all status of information. The battery status can be displayed using LCD display. This is used to display the output voltage and output current of the given circuit. A. PIC microcontroller Fig.3: LCD Display III SOFTWARE REQUIREMENTS The PWM (Pulse Width Modulation) technique is employed by the PIC16F77A microcontroller to recharge the battery. Harvard architecture concept differs than Von-Neumann s and it is of type RISC [Reduced Instruction Set Computer].

4 In Harvard architecture contains mainly data bus and address bus thus a greater flow of data is possible through the central processing unit and of course a greater speed of work. Makes it further possible for instructions not to have to be 8-bit words by using PIC microcontroller the components required in the system is minimized and it works when power is on and reads battery voltage with the help of ADC and will be displayed on the LCD. Fig.4: PIC Microcontroller [PIC 16F877A] PIC 16F877A uses 14 bits for instructions which allows for all instructions to be one word instructions. It is also typical for Harvard architecture to have fewer instructions to be one word instructions and to have instructions to be executed in one cycle. The major advantage with this architecture is that while an instruction is being executed the next can be fetched. The execution speed is doubled.we find this architecture in PIC16F877A. B. Proximity Sensor The ambient light sensors and proximity detection product family provide both ambient light sensing (ALS) and proximity detection in a single device. The ALS approximates human eye response to lighting condition and through a variety of attenuations materials. The proximity detection feature allows a large dynamic range of operation for use in short distance detection behind dark glass such as in a cell phone for mobile display and monitors. Fig.5: Proximity sensor in the front panel of mobile

5 IV METHODOLOGY Mobile battery can be charged from solar panel or from adopter battery is charging with solar panel of 6V, then ADC1 pin of PIC microcontroller is activated correspondingly ADC0 pin is disabled. The PIC microcontroller mainly performs two functions. The former is Charge Control operation of battery that is if battery stamina is comes down to 1.4V then the battery is automatically starts charging using solar panel. When battery is fully charged up to 3.85V, then the ADC1 pin is disabled. Also battery status is displayed on LCD. The second function is to display the output voltage on the LCD. We are going to utilize two batteries, one to store the output voltage of solar panel another is to drive the PIC microcontroller. IC FM63160FE is used to boost up the incoming voltage from panel and also to drive the PIC microcontroller Fig. 5: Block Diagram of the System Over voltage protection circuit includes charge control unit, battery, proximity sensor and PIC microcontroller for the battery status sense. The PIC performs battery voltage readings during the rest period of the charge cycle, this status information reading is used to protect the battery from overcharging. By using over voltage protection circuit we can protect our battery from over charge. Charge control circuit contains two-way Switch. By using this unit we can apply proper battery voltage to our cell phone battery and reduced the explosion of battery. V IMPLEMENTATION The implementation of the proposed system includes solar panel, ICFM6316FE, storage batteries, PIC microcontroller with LCD display. The figure 7 describes the operation of proposed system. The input voltage from solar panel (6V, 0.33A) is given to the IC FM6316FE which boost up the voltage and corresponding output will be stored in a battery1 and battery2. The battery 1 is used for storage purpose and battery2 is connected to another IC FM6316FE and its output is used to drive the PIC microcontroller.adc0 pin and ADC1 of PIC16F877A is given to solar panel and battery2 respectively. Before given to the input supply the ADC pin is disabled and it will display on LCD as shown in the figure 8. When the battery is charging from solar energy it indicated on the LCD as shown in the figure 9. When the battery is fully charged it is also displayed on LCD as shown in the figure 10

6 Fig.7: Proposed System. Fig.8: Battery Status Indicating No Input Supply to Charge

7 Fig.9: Charging Battery Status Fig. 10: Fully Charged Battery Status VI APPLICATIONS For low-power portable electronics, like calculators or small fans, a photovoltaic array may be a reasonable energy source rather than a battery. By using over voltage protection circuit we can protect our battery from over charging. Charge discharge control circuit contains two-way Switch. VII ADVANTAGES Cost Effective: Compared to the other mobile chargers, the solar chargers are cost effective as it absorbs power from the sun. It does not require electric power. Emergency Purposes: Another benefit is that it hardly requires any electrical outlet. It can therefore be used during emergencies and outdoor purposes. Presence of control system can avoid explosion of battery that connected electric socket. VIII CONCLUSION This section ends with the charging Mobile battery using solar energy, so optimum utilization of non conventional energy is done. The sunlight energy is converted to electrical energy to drive a battery. The implemented system charges the battery in dual mode i.e by using sun light and also from electric source. Charge controlling is done using PIC microcontroller and IC FM6316FE. The battery status, overcharging and deep

8 discharging is displayed on LCD. The future work is carried out by using the MPPT tracking system so that the solar panel charging even in shadow region. REFERENCES [1] F.Sani, H.NYahya, M. Momoh, I.G.Sidu and D.O. Akpootu, Design and Construction of Microcontroller Based Charge Controller for Photovoltaic Application, IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE), Vol 9, Issue 1, pp 92-97, Jan [2] Filipe Távora, Andrea Sarmento Maia, Solar Battery Charger for Portable Devices Application, pp 1-27, June [3] Christian Schuss, Timo Rahkonen, Solar Energy Harvesting Strategies for Portable Devices Such as Mobile Phones, Proceeding of the 14 th Conference of Fruct Association, pp , [4] P.H.Patil, Poonam Undre, Shriti Wavhal and Pooja Patil, Solar Based Inverter and Charger, International Journal of Scientific & Engineering Research, Vol 4, Issue 7, pp 79-82, July [5] Qutaiba I, Design & Implementation of a Mobile Phone Charging System Based on Solar Energy Harvesting, Iraq Journal on Electrical and Electronic Engineering, Vol 7, pp 69-72, Jan [6] Yousif I, Al-Mashhadany, Hussain A. Attia, Novel Design and Implementation of Portable Charger through Low-Power PV Energy System, American University of Ras Al Khaimah, UAE, Vol. 2, No 12, pp , [7] Lijun Gao, Roger A. Dougal, Parallel-Connected Solar PV System to Address Partial and Rapidly Fluctuating Shadow Conditions, IEEE Transactions on Industrial Electronics, Vol 56, pp , May [8] Ian Y.W. Chung and Yung C. Liang, A Low Cost Photo Voltaic Energy Harvesting Circuit for Portable Device, IEEE PEDS 2011 Singapore, pp , Dec [9] Hussain A. Attia, Beza Negash Getu, Hasan Ghadban, Ahmed K. Abu Mustafa, Portable Solar Charger with Controlled Charging Current for Mobile Phone Devices, International Journal of Thermal and Environmental Engineering, Vol 7, No. 1, pp 17-24, [10] Jaya N. Ingole, Madhuri A. Choudhary, R.D. Kanphade, PIC Based Solar ChargingController For Battery, International Journal of Engineering Science and Technology (IJEST), Vol. 4, No.02, February 2012.