31-10-2016, 12:40 PM
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Abstract:
This paper describes coin based mobile
charger using solar tracking system. Mobile phone’s
become a major source of business/personal
communication; the mobile phone business is
currently worth billions of dollars, and supports
millions of phones. The need to provide a public
charging service is essential. Many critics argued
that a public mobile phone charging service is not a
lucrative business because most users can charge
their phones at home, in their office or in their cars.
Coin operated mobile phone charger is new
business milestone because many are attending
business conventions and forgetting their charger at
home or in hotel rooms. Students and many people
use the public transportation that don’t know that
their level of their battery is low are prospective
customers for coin operated mobile phone charger
service. Recommended locations include: Hotels,
Conference centres, Exhibition halls, Serviced
offices, Exchange halls, Motels, Leisure centres,
Health clubs, Training centres, Golf clubs, Retail
outlets, Shopping malls, Internet cafes, Universities,
Colleges, Hall of residence, Airports, Train
terminals, etc., so that the mobile phone users can
reactivate a low or dead battery by simply plugging
in and charging for one rupee. This is designed
based on ATMEL 89c51 a 40-pin micro controller
that does the countdown timings for a period of 3
minutes with LCD displays showing the actual time
left. During the timing period a relay output is
latched and finishing timing in progress.
. Introduction
Usually ordinary solar panel is always faces
only in one direction. Because of this reason the solar
panel may not get sufficient sun rays to work. In this
work SOLAR PANEL CONTROLLER AND POWER
OPTIMIZATION is done in order to overcome this
defect. Here the panel will rotate according to the
readings read by the LDR. So it will utilize the full sun
light to work & power optimization is also done by using
the LDR.
This work mainly designed to control the solar
panel automatically, maintains face of the solar panel
towards the sun. This is done by controlling the
mechanical movement of the solar panel. Usually sun
rises at east and sets at west. In ordinary system, if it
faces towards east then it cannot change the direction
towards sun during sunset. Because of this reasons
solar panel may not get sufficient sun rays to work.
These problems are overcome by using this
work. In this work we also build a very good micro
controller based solar charger. The coin-based mobile
battery charger developed in this work providing a
unique service to the rural public where grid power is not
available for partial/full daytime and a source of revenue
for site providers. The coin-based mobile battery charger
can be quickly and easily installed outside any business
premises.
The mobile phone [1] market is a vast industry,
and has spread into rural areas as an essential means
of communication. While the urban population use more
sophisticated mobiles with good power batteries lasting
for several days, the rural population buy the pre owned
mobile phones that require charging frequently [2].
Many times battery [3] becomes flat in the
middle of conversation particularly at inconvenient times
when access to a standard charger isn't possible. The
coin-based mobile battery chargers are designed to
solve this problem. The user has to plug the mobile
phone into one of the adapters and insert a coin; the
phone will then be given a micro-pulse for charging. It
does not bring a mobile from 'dead' to fully charged
state.
The charging capacity of the mobile is
designed with the help of pre defined values. It is, of
course, possible to continue charging the mobile by
inserting more coins. This compact and lightweight
product is designed to cater for the growing number of
rural mobile users worldwide. A suitable microcontroller
is programmed for all the controlling applications. The
source for charging is obtained from direct power grid
and solar energy [4] in case of non availability of grid
power.
2. Basic Assumptions
The design of coin based universal mobile battery
charger is based on the following assumptions:
Maximum solar energy is used for charging the
lead acid battery inside the mobile battery
charger to keep it charged fully all the time
The charging current is up to 4.5AH @ 6vDC
and this takes care of the mobiles
manufactured by Nokia, Sony-erricson,
Blackberry, HTC and others of first and second
generation mobiles.
A single solar panel of size 635x550x38 mm,
37WP capable of supplying upto 2.0 amp is
used.
Provision to charge maximum 10 different
types of mobiles is provided.
Proposed System Architecture
3.1. Solar Tracking System
The mechanical movement of the solar
controlled through the stepper motor [5]. 3 LDR’s will be
placed on arch. So according to the sun movement LDR
intensity will be varied where the sun light intensity is
more LDR intensity will be less and depending upon
LDR intensities stepper motor will be rotated to the side
where the LDR intensity is found to be less so that solar
panel is also rotates.
Power optimization is done by using LDR. If the
surrounding light is less then LDR reads maximum.
According to the value of LDR the ADC shows the
reading. The ADC will send this value to microcontroller.
According to the value sent by the ADC the
microcontroller glows the LED through relay. If the
intensity of the light is more means all the LED array will
be OFF. Depending upon the intensity of the light LED
arrays will be switched ON or OFF.
Power Supply
The input to the circuit is applied from the
regulated power supply [6]. The AC input i.e., 230V from
the mains supply is step down by the transformer to 12V
and is fed to a rectifier. The output obtained from the
rectifier is a pulsating DC voltage. So in order to get a
pure DC voltage, the output voltage from the rectifier is
fed to a filter to remove any AC components present
even after rectification. Now, this voltage is given to a
voltage regulator to obtain a pure constant DC voltage.
3.3.1. Input Stage
The mobile battery charger starts charging a
mobile connected to it, when a coin is inserted at the
coin insertion slot at the input stage. The type of coin
and the size will be displayed at the LCD display for the
user, so as to ensure correct coin insertion. Any other
coin, if inserted in the slot will be returned to refund box.
A mechanical slot is attached with electrical triggering in
coin insertion slot, if the correct coin is inserted, it sends
a pulse to the control unit authorizing the start of
charging the mobile battery connected to the device.
Then the coin insertion slot accepts the coin into the
battery charging unit and start charging the mobile
battery for a specific period controlled by the software of
the microcontroller [1].
3.3.2. Controller
This section acts according to the input signal
from the sensor circuit. Coin accepted or rejected is
based on the diameter of the coin. This invokes
microcontroller along with LCD interface displays the
selection of mobile option if particular mobile is selected
for charging the corresponding routine is activated and
charge the mobile for a particular duration of time .When
the routine completes, it indicates charge complete
message through LCD display. Similarly the same
procedure is followed for charging more than four
different mobiles simultaneously [1] .The simple routine
is indicated through flowchart as shown in the Fig 4.
3.3.3 Output and Display
The LCD displays all the information to the
customer as and when required. When the mobile
battery is connected, it displays” Insert Coin”. While
charging it displays “Charging” and at the end of
charging cycle it displays “Charge completed”. For
charging continuously the coin has to be inserted when
the display shows “Charge Completed” The output has
10 terminals for connecting different types of mobile
batteries [7] and 7 of them are internally connected for
charging mobile batteries of different make