solar powered smart pedestal lighting system
DESCRIPTION
The report of the project Solar Powered Smart Pedestal Lighting System.TRANSCRIPT
SRI MADHWA VADIRAJA INSTITUTE OF TECHNOLOGY AND MANAGEMENT
Solar Powered Smart Pedestal Lighting System
An innovation to light up the rural India smartly (A project sanctioned by Vision Group on Science and Technology –Govt. of Karnataka)
Guide: Asst. Prof. Rajesh Nayak
Team Members
Pranav Rao
3rd Year
Electronics and Communications Engineering
S R Dhanush
3rd Year
Electronics and Communications Engineering
Ajesh
3rd Year
Electronics and Communications Engineering
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ABSTRACT
This project aims at harvesting the energy from renewable energy sources like sun and to effectively
use the harvested energy for the benefit of the remote villages (villagers) facing serious power problems.
The main aim of the project is to provide “Smart Street Lighting system” powered with solar energy to
assist villagers during night time.
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ACKNOWLEDGEMENTS
We have taken efforts in this project. However, it would not have been possible without
the kind support and help of many individuals especially Prof. Dr. Ravindra who showed us the right path
to proceed and Prof. Dr. Nagaraj Rao who encouraged us venture into this opportunity, and our project
guide Asst. Prof. Rajesh Nayak. We would also like to thank Mr. Vignesh Kalathur whose ideas and skills
have helped us to complete our model.
We are highly indebted to Sri Madhwa Vadiraja Institute of Technology and Management for providing
the necessary infrastructure and facilities and also for their support in completing the project.
We would like to express our gratitude towards member of Selco Solar Power Systems for their kind co-
operation and encouragement which helped us in completion of this project.
Our thanks and appreciations also go to our classmates in developing the project and people who have
willingly helped me out with their abilities.
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Contents 1.Introduction ................................................................................................. Error! Bookmark not defined.
2.Background .................................................................................................. Error! Bookmark not defined.
3.Solar Powered Smart Pedestal Lighting system ......................................................................................... 7
4.Function Description .................................................................................................................................. 8
5.Block Diagram ............................................................................................................................................. 8
Description of the Blocks ........................................................................................................................... 9
Dusk-Dawn Regulators (DDR) ................................................................................................................. 10
Motion Sensors ....................................................................................................................................... 11
Lead-acid batteries .................................................................................................................................. 12
LED Panel ................................................................................................................................................. 14
6.Power Consumption ................................................................................................................................. 15
7.Integration of the units into a System ...................................................................................................... 16
8.Evaluation .................................................................................................... Error! Bookmark not defined.
Conclusions .................................................................................................................................................. 18
Bibliography ................................................................................................................................................. 19
Expenditure Listings .................................................................................................................................... 20
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1. Introduction The energy consumption in entire world is increasing at the fastest rates due to population growth and
economic development and the availability of energy sources remains woefully constrained. Resource
augmentation and growth in energy supply has not kept pace with increasing demand and, therefore, India
continues to face serious energy shortages.
The project aims at harvesting the energy from renewable energy sources like sun and to effectively use
the harvested energy for the benefit of remote villages (villagers) facing the serious power problems. The
main aim of the project is to provide a “Smart Street Lighting System” powered with solar energy to assist
the villagers during night time. We use the word “smart” because the system not only provide power to
the street lights but also helps in detecting the direction of movement of the pedestrian and helps him by
means of illuminating the path of movement till the near next street light. By integrating the entire street
lights with Smart street light system it is possible to systematically help the pedestrian to reach the
destination in the remote rural areas which are facing serious electric power supply problem. The same
system can also be used for the House lighting purpose as it works on the principle of sensing the thermal
signature of human body to switch the light, there by the system helps in saving the electric power.
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2. Background The key indicators of India’s energy problems include; Over 40 per cent of the households
(particularly rural areas) in India still do not have electricity, about a third of our total primary energy
supply to rural areas still comes from non-commercial sources (biomass, dung) and currently India faces
an enormous demand supply gap of about 15-25% energy shortage. Due to shortage of the energy supply
till today several villages have not facilitated with electricity and even if provided, the supply of the
electricity is limited to few hours in a day and are facing serious problems due to unlimited power cuts.
During the day time we get enormous amount of light energy from sun and the problem for pedestals
are common during the night time. Though most of the streets are equipped with street lights in each and
every village areas but due to the uncontrolled power failures/power cut it is becoming a serious problem
for villagers to commute for irrigational field work during the night time due to unlimited power cuts
which indirectly affect the crop yield of the farmer. Such trends often discourage the villagers taking up
agriculture which is the backbone of our economy. It also poses a serious threat to the villagers from
physical hazards such as thieves, snakebites, etc.
Installation of street lights may seem a pleasant option but absence of electricity reducers their presence
to null. Hence the best option is to install solar powered street lights and moving a step ahead, we
designed this ‘Solar Powered Smart Pedestal Lighting System’.
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3. Solar Powered Smart Pedestal Lighting system
The Smart Solar Street Light consists of motion sensors which detect the presence of pedestrians in its
proximity and the lights turn on which otherwise is ’off’. High power LEDs are used for illumination. The
system would derive the energy from the solar panel installed at the top of the unit whose generated
electricity is stored in Lead- Acid battery.
The ‘Solar powered Smart Street Lighting System’ is an integration of number of such units of the smart
street light which would be installed in the village such that the units could provide continuous light to
pedestrians at night assisting him to reach his destination. The above system has two main advantages-
Reduces the wastage of harvested energy and hence can be deployed in regions with very low
sunlight also
Simple design and hence easier maintenance
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4. Function Description The design basically includes three working modes:-
OFF mode: When there is enough natural light in the surrounding i.e. during the daytime, the
entire system is switched off and the batteries are charging
Active mode: When the natural light drops below a certain level the system automatically turns
on and the motion sensors are powered
ON mode: On the presence of pedestrians, the sensors turn the relays on which in turn switches
on the LED lights. These lights turns off after a fixed period of time
5. Block Diagram
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Description of the Blocks Each of the blocks are described clearly in the following sections:
Solar Panel Solar panels are used to power the whole system. A solar panel (PV panel) is made of the natural
element, silicon, which becomes charged electrically when subjected to sun light. Solar panels are
directed at solar south in the northern hemisphere and solar north in the southern hemisphere (these are
slightly different than magnetic compass north-south directions) at an angle dictated by the geographic
location and latitude of where they are to be installed. Typically, the angle of the solar array is set within a
range of between site-latitude-plus 15 degrees and site-latitude-minus 15 degrees, depending on whether a
slight winter or summer bias is desirable in the system. Many solar arrays are placed at an angle equal to
the site latitude with no bias for seasonal periods.
This electrical charge is consolidated in the PV panel and directed to the output terminals to produce low
voltage (Direct Current) - usually 6 to 24 volts. The most common output is intended for nominal 12
volts, with an effective output usually up to 17 volts. A 12 volt nominal output is the reference voltage,
but the operating voltage can be 17 volts or higher much like your car alternator charges your 12 volt
battery at well over 12 volts. So there's a difference between the reference voltage and the actual operating
voltage.
The intensity of the Sun's radiation changes with the hour of the day, time of the year and weather
conditions. To be able to make calculations in planning a system, the total amount of solar radiation
energy is expressed in hours of full sunlight per m², or Peak Sun Hours. This term, Peak Sun Hours,
represents the average amount of sun available per day throughout the year.
Fig. Two Solar Panel Connected in Series
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The output of a solar panel is usually stated in watts, and the wattage is determined by multiplying the
rated voltage by the rated amperage. The formula for wattage is VOLTS times AMPS equals WATTS. So
for a 12 volt 60 watt solar panel measuring about 20 X 44 inches has a rated voltage of 17.1 and a rated
3.5 amperage.
V x A = W
17.1 volts times 3.5 amps equals 60 watts
Two solar panels 45 watts each would be connected in series combination. In an average the solar panel
would be receiving direct sunlight for period of 7 hours per day. So by simple calculation we can find that
on an average day we can store approximately 0.63 kWh of power per day.
Dusk-Dawn Regulators (DDR)
It charges the battery during the day time and turns on the load at dusk. It turns off the load at dawn. It not
only charges the battery from solar panel in the optimum way using the fullest power without much loss
but maintains the SOC of the battery under charge. Input losses are practically negligible due to high
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efficiency charging in shunt mode. Similarly battery loss in load circuit is less than 3% making it better
than 97% efficient. Its pulse-width-modulation (PWM) keeps the battery in excellent SOC to have
prolonged life of battery.
FEATURES:
Automatic dusk to dawn operation.
Suitable to drive CFL or LED lights.
Day time consumption < 1mA.
True indication of battery charging.
Battery low indication.
Over load protection and indication. Reset switch provided.
Motion Sensors
A standard PIR sensor is used as the movement detector. The 4 sensors interfaces to the PICAXE (IC1)
on input 1, input 2 input3, input4. These pins are pulled low via isolation diodes D2, D3, D4, D5 and the
normally open (NO) output of the sensor whenever movement is detected. It can also be pulled low by
transistor Q1, Q2, Q3, Q4which acts as a simple inverters for sensors with normally closed (NC) outputs
(Fig 3).
So that the lights aren’t needlessly switched on during the day, a light-dependent resistor (LDR) is used
as an ambient light sensor. Together with a 100kΩ resistor, the LDR forms a simple voltage divider,
which converts its changing resistance to a changing voltage at the micro’s analog input (pin 7). As light
falling on the sensor decreases, its resistance increases, resulting in less voltage at the analog input. Below
a preprogrammed threshold voltage, it is assumed to be night-time.
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The observed range of the PIR sensors is 6-7 metres.
Lead-acid batteries Lead-acid batteries are the most common in PV systems because their initial cost is lower and because
they are readily available nearly everywhere in the world. There are many different sizes and designs of
lead-acid batteries, but the most important designation is that they are deep cycle batteries. Lead-acid
batteries are available in both wet-cell (requires maintenance) and sealed no-maintenance versions. AGM
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and Gel-cell deep-cycle batteries are also popular because they are maintenance free and they last a lot
longer. The Deep Cycle batteries used are designed to be discharged and then re-charged hundreds or
thousands of times.
The battery should have sufficient amp hour capacity to supply needed power during the longest expected
period "no sun" or extremely cloudy conditions. A lead-acid battery should be sized at least 20% larger
than this amount.
We used a 60Ah battery for the design. The wattage of the LED panel is roughly 30 Watts (considering all
the subunits and the sensor units).
On a good sunny day, 0.63 kWh of power can be stored which could last for up to 4 days with little
sunlight.
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LED Panel
LED panel is built in consists of sub-units within it, each inclined at 30 degrees towards the path it is
illuminating. Assuming the unit is fixed in a junction of four roads, we have designed the panel as shown
in the above figure. 3 W LEDs are used in the design.
LED bulbs in general are brighter than incandescent lamps and CFLs of the same wattage. A 3-watt LED
bulb may produce anywhere between 240 to 320 lumens of illumination. Lumens is a measure of light.
‘Lumens per watt’ is the measure to identify how much light is produced for the energy or wattage drawn.
Accordingly, the minimum efficiency of a 3 Watt LED bulb will be 80 lumens/watt. A 20 Watt halogen
bulb on the other hand may produce 350 lumens of energy on average, with an efficiency of 17 lumens
per watt used.
3 Watt rated LED bulbs consume very low power, usually less than 4 watts. A single 3 Watt LED bulb
can be equivalent to a 30 Watt fluorescent lamp. It is possible to choose between white light LED bulbs,
warm light LED bulbs and colored light. White light bulbs can last more than 50,000 hours. On the other
hand colored LEDs can last twice as long at more than 100,000 hours.
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6. Power Consumption Two solar panels 45 watts each would be connected in series combination. In an average the solar panel would be receiving direct sunlight for period of 7 hours per day. Hence using the equation
Power = (power in wattage) × (hours)/1000
So by simple calculation we can find that on an average day we can store approximately 0.63 kWh of power per day.
A set of ten LEDs will be used which will require 0.36 kWh of power for twelve hours .This value is
compatible with the designed solar power unit, leaving enough power for the microcontroller unit and
required backup.
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7. Integration of the units into a System So we have seen the working and specifications in the previous section for one unit of a Smart Solar
Street Light. Let us abbreviate it as SLU (Street Lighting Unit). Number of SLUs are installed around the
village along the street with an average distance of 12 meters between each unit. Thus a pedestrian is
always within the range of the SLU which illuminates his path.
The path of a person walking at night is continuously illuminated by one or the SLU. He gets a feeling
that the light is following him!
SLU
SLU
SLU
SLU
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8. Evaluation Implementing and analyzing the prototype we built, we found that the design could be largely efficient
in street lighting in not only villages but also any other place as well. Also for the specifications, two
Street Lighting units could be powered. Hence we found the system really energy efficient. The following
listing shows the advantages of the system:-
Reduced battery capacity and solar panel wattage
Reduced cost
Low maintenance cost
Simple operation
Suitable for regions with limited sunlight also
One shortcoming of our design is we underestimated the amount of power required to power the system.
Since the lights would be turned on an average of 3 hours per night (which we calculated for 10 hours per
night in the initial stages), the specifications of the solar panel and the lead-acid storage battery is much
high compared to the actual requirement which cost us more.
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Conclusions
The successful implementation of the project would help the remote areas which are facing severe
Power supply problems. The lighting system uses LED’s and hence the power consumed will be much less
compared with the conventional lighting systems. Further if similar lighting systems are implemented for
normal street lighting by the government, we would be saving a great amount of electricity which otherwise is just wasted…
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Bibliography
[1] www.main.org/polycosmos/glxywest/vimanas.htm - Indian Flying Machines
[2] www.electronicsforyou.comI.
[3] http://www.triplepundit.com/2011/08/solar-farming-potential-india/- Solar Farming
[4] http://en.wikipedia.org/wiki/Solar_cell
[5] http://www.planetarypower.com.au/solar_panels.htm
[6] Element14 – to look up devices, ICs
[7] Physics of Solar Cells- A Text for Undergraduates, J Nelson
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Expenditure Listings
Particulars Cost
Customised Solar system 18025
Electronic Components 7338.91 1874.09
Stationaries 814
Travelling 600
Others 572.09
Fund Received 40000 0
Expenditure 27350
Balance Amount 12650