SMART SOLAR STREET LIGHTING

SYSTEM A Project presentation by K.KIRAN KUMAR P.PRANEETH Y.HEMANTH

CONCEPT The system contains solar panels, light sensors, inverters at

the grid and lamp posts across the transmission lines. During brighter lighting, the solar panel has to capture and

store solar energy in the batteries present in the grid. To store maximum energy, the panel has to track the sun so

that maximum intensity of light is obtained on the panel.

When the conditions turn darker, the inverter will be turned on thus supplying AC voltage across the transmission lines.

Locally, every light post is mounted with motion sensor which switches on the light for a period of time and then switches it off when a motion is sensed nearer to the lamp post.

FEATURES Works on Solar Energy-no external power source is required. Sun Tracking mechanism-to capture maximum energy Automated switching-light remain off during bright lighting

conditions and switch on when an animal or automobile motion is sensed during darker conditions.

Applicable for very long range-as AC is transmitted, lights which are far away from the grid can also be powered.

REALIZATION BY A PROTO TYPE The proto type makes use of LDR as light sensor, a

10W,12V solar panel,12V DC motor, 7.5Ah lead acid battery ,an inverter, PIR motion sensor, relays, Atmega-16- a micro controller to control the circuit and a AC lamp to demonstrate working.

BLOCK DIAGRAM

CIRCUIT DIAGRAM

FUNCTIONAL DESCRIPTIONLDR is a photo dependent resistor whose resistance varies with light intensity and Thus can detect change in light intensities.

This prototype makes use of three LDRs aligned on the solar panel, two for tracking (X,Y) and one (Z) for switching.

Initially, the panel is parallel to earth, voltages on LDR are fed to ADC of Atmega 16.

Atmega 16FEATURESThe ATmega16 is a 40 pin low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture.16 Kbytes of In-System Self-programmable Flash program memory.512 Bytes EEPROM.1 Kbyte Internal SRAM.Write/Erase Cycles: 10,000 Flash/100,000 EEPROM.131 Powerful Instructions – Most Single-clock Cycle Execution.32 x 8 General Purpose Working Registers.On-chip Analog Comparator.Programmable Watchdog Timer with Seperate On-chip Oscillator.Master/Slave SPI Serial Interface.

Two 8-bit Timer/Counters with Separate Prescalar, Compare. One 16-bit TImer/Counter with Seperate Prescaler, Compare

and Capture mode. Real Time Counter with Seperate Oscillator. Four PWM Channels. Programmable Serial USART. 8-channel, 10-bit ADC. Byte-oriented Two-wire Serial Interface.

ANALOG TO DIGITAL CONVERTER

FEATURES

10-bit Resolution0.5 LSB Integral Non-linearity±2 LSB Absolute Accuracy13 μs- 260 μs Conversion TimeUp to 15 kSPS at Maximum Resolution8 Multiplexed Single Ended Input Channels0 - VCC ADC Input Voltage RangeADC Start Conversion by Auto Triggering on Interrupt SourcesInterrupt on ADC Conversion Complete

Analog to Digital Converter Block Schematic

DURING BRIGHT LIGHTLight intensity on Z is high

Intensities on X and Y are compared, If intensity on X is high, panel is tilted anti-clock wise by the DC motor controlled by

ATmega16. If intensity on Y is high, panel is tilted clockwise by the DC motor controlled by ATmega16. Panel remains still if intensities on X and Y are equal.

The energy captured by the solar panel is stored in the battery

DURING POOR LIGHTING (DARKNESS)Intensity on Z goes low.

The voltage available in battery is applied across PIR motion sensor and the inverter.

The position of the solar panel is reset, i.e., parallel to earth.

INVERTERWhy inverter?

Working model consists a large number of lights posted at very long distances from the grid. If DC is transmitted lot of losses occur and if replaced by AC, voltage can be amplified locally by transformers.

The inverter used in this project is non sinusoidal.

It consists a astable multivibrator generating a 50Hz square wave.

The square wave is applied along gates of two MOSTETs which amplify the square wave.

The MOSFETs work in push pull configuration , puts out a square wave of 30Vp-p.

CIRCUIT DIAGRAM OF INVERTER

CD4047BE ASTABLE FREE RUNNING MODE FEATURES

Free-running or gatable operating modes

50% duty cycle

Oscillator output available at pin 13

Good astable frequency stability

Requires an external capacitor (between pins 1 and 3) and an external resistor (between pins 2 and 3) to determine the frequency.

CD4047 BE block diagram

IRFZ44NAn n-channel enhancement mode power MOSFET.

TO-220 package.

continuous drain current of 49 A at 25 °C, and 35 A at 100 °C

The low thermal resistance

ideal component for switched mode power supplies, and general switching applications.

OUTPUT OF CD4047BE

Out put at pin 10

OUTPUT OF IRFZ44N

Output across drain pins of the MOSFETs

OUTPUT OF THE TRANSFORMER

The out put of the inverter (50W) is applied to the pole of a relay controlled by a motion sensor.The motion sensor used is a PIR sensor whose output sets high when a motion is sensed.

PIR MOTION SENSORAbbreviated as Passive Infra Red Sensor.

Basically made of a pyroelectric sensor, which can detect levels of infrared radiation.

Everything emits some low level radiation, and the hotter something is, the more radiation is emitted.

We are looking to detect motion (change) not average IR levels. So, The sensor in a motion detector is actually split in two halves.

The two halves are wired up so that they

cancel each other out. If one half sees more or less IR radiation than the other, the output will swing high or low.

When the sensor is idle, both slots detect the same amount of IR, the ambient amount radiated from the room or walls or outdoors.

When a warm body like a human or animal passes by, it first intercepts one half of the PIR sensor, which causes a positive differential change between the two halves.

When the warm body leaves the sensing area, the reverse happens, whereby the sensor generates a negative differential change. These change pulses are what is detected.

The out put of the PIR sensor is fed to BISS0001-a micro power PIR motion sensor.BIS0001 senses the outputs of PIR sensor and sets a high output when a motion is sensed.BIS0001 has facility to set sensitivity and time interval for which the output must remain high when motion is sensed.

The element window of PIR is very small to get a large area under its coverage, we don’t want two really big sensing-area rectangles, but rather a scattering of multiple small areas.

So what we do is split up the lens into multiple section, each section of which is a fresnel lens. The Fresnel lens condenses the IR radiation and focuses it on to the element window.

Top and bottom views of Fresnel lens

When a motion is sensed, the output of the PIR motion sensor is high, which is in turned applied as coil voltage of the relay.

Thus, the voltage generated by the inverter is applied across the lamp and the lamp glows. The entire system uses the energy stored in the battery, no external power source is required.

Power distribution block diagram

CONCLUSIONSThe present project is a proto type for Smart Solar Street Lighting System.

The principle of working is same for the working model.

The working models does not have a single light, a number of lights will be connected in parallel with a separate motion sensor for every light (each motion sensor requires a local rectifier as it cannot operate on AC) to switch them whenever motion of body or automobile is sensed.

To energize this array of lights and sensors, the system needs greater power source and thus solar panels of high wattage and batteries of greater capacities are required.

DC motors with high torque must be installed to facilitate the sun tracking and gear mechanisms or belt mechanisms can be deployed in cases where multiple solar panels are installed.

PROTO TYPE

Submitted Under the guidance of

A.N.Reddy, R.Divya Praneetha, Head, Training and Development, Assistant Professor, Thrive Solar Energy Pvt Ltd. Vignan’s University.