Electrical & Power Electronics


Hybrid Solar Charger

Efficiency of a solar charging system depends on the weather conditions. Usually the solar panel gets four to five hours of bright sunlight in a day. If the weather is cloudy or rainy, it affects the charging process and the battery does not attain full charge. This proposed hybrid solar charger can solve the problem as it can charge the battery using both solar power as well as AC mains supply. When output from the solar panel s above 12 volts, the battery charges using the solar power. When the output drops below 12 volts, the battery charges through AC mains supply.


The objective of this project is to develop a low cost, compact and high reliable device for the hybrid solar charger. The project design involves a 10W solar panel, operational amplifier , transistor BC547, 12V single change over relay , step-down transformer and a few other components. In bright sunlight, the 12V, 10W solar panel provides up to 17 volts DC with 0.6-ampere current, When output from the solar panel is 12 volts or more the battery is charged by solar supply through enegises relay and this charging status is indicated by a LED ON. When output from the solar panel drops below 12 volts, output of the comparator turns low and the relay de-energizes. Now the battery gets charging current from the transformer-based mains power supply through the normally- closed (N/C) contact of the relay. The operational amplifiers as comparator and zener diode used which comprises the solar voltage for chargable voltage limit 12v. There are a rectifying diode and smoothing capacitor provides charging current from mains while solar power goes below 12v. Thus a battery is kept in continuous charging even if low solar light using this hybrid solar charger.

Temperature Meter Display

This temperature meter uses the precision micro power centigrade sensor IC LM35. The output voltage of the IC is linearly equal to +10mv per degree centigrade. The temperature level is displayed through LED readout. The circuit uses the precision temperature IC LM35. This three pin transistor like IC give output linearly equal to +10mV per degree rise in temperature. It can measure temperature between -4 degree to +110 degree centigrade. Its related type LM34 is Fahrenheit sensor and its output is equal to -10mV per degree Fahrenheit. Output of IC1 is directly given into the input of the display driver IC LM3914. It is a monolithic integrated circuit with 10 active low outputs that can drive 10 LEDs directly without a current limiting resistor.

The internal circuitry of the IC adjusts the current passing through the LEDs. The input of LM 3914 is very sensitive and its outputs 18 – 10 sinks current one by one as the input receives an increment of 125 milli volts. Here only 6 outputs are used to drive 6 LEDs. More LEDs can be included in the remaining outputs if required. As the IC LM35 senses temperature rise, LEDs one to six light up. If the sensitivity is not high, VR2 can be omitted. Then output of IC LM35 should be directly connected to the input of IC LM3914.

Dual Power Generation by Solar and Windmill Generator

Renewable energy has been on an increasing demand in the recent due to over stress on non-renewable resources and their increasing cost. Thus producing electricity with the use of renewable resources like Wind and Solar has been taken up in this project. A Windmill, which rotates when there is enough wind, generates electricity owing to magnetic coupling between the rotating and stationary coil. A horizontally rotating prototype of Windmill is being used in this project. Silicon based wafers which are cascaded together to form a Solar Panel is being used in this project to generate electricity. Dual Power Generation Solar + Windmill System harnesses both the Solar and Windmill i.e, Wind Turbine Generator to charge a 12V Battery. The System is based on Atmega328 microcontroller which smartly senses and charges the battery while displaying the voltage on the LCD. The Windmill, when in enough wind to drive it, generates power enough to charge a battery. Similarly, the Solar Panel which is mounted on a rotating panel which sets itself to maximum exposure of the daylight to generate energy enough to charge the battery. Since both of them simultaneously can work in favorable natural conditions, both can charge the battery at a faster pace than they would had individually. Thus this project is an example how natural resources can be efficiently harnessed to produce electricity at a faster pace and cheaper rate.

IOT Smart Energy Grid

The Electric power generate authorities supply electricity to all the consumers through intermediate controlled power transmission hubs known as Electricity Grid. Sometimes problems arise due to failure of the electricity grid leading to black out of an entire area which was getting supply from that particular grid. This system aims to solve this problem using microcontroller device and Internet of things (IOT) system as means of communication and also tackling various other issues like power theft which a smart system can deal with to avoid unnecessary losses to the Energy producers.


The project system design involve an Arduino family microcontroller to control the various activities of the system. The system communicates over internet by using Wi-Fi technology. An op-to isolated relay switches are used to switching energy grid and consumer load .A bulb is used in this project to demonstrate as a valid consumer and a bulb to demonstrate an invalid consumer. The foremost thing that this project facilitates is re-connection of transmission line to active grid. If an Energy Grid becomes faulty and there is an another Energy Grid, the system switches the Transmission Lines towards this Grid and this information of switching over this Grid is updated over IOT webpage where the authorities can login and can view the updates. Apart from monitoring the Grid this project has advances capabilities of monitoring energy consumption and even detect theft of electricity. The amount of power delivered from grid and consumed are measured using Current sensors connected at grid and consumer side, and voltage and frequency are measured using an Op-amp circuitry. The amount of electricity consumed and the estimated cost of the usage also gets updated on the IOT web page along with the Energy Grid information. Theft conditions are simulated in the system using two switches. Switching one each time will simulate a theft condition and also will notify the authorities over the IOT web page.


Thus, this IoT Smart Energy Grid system makes sure that the electricity supply is continuous and helps in maintaining a updated record of consumption and theft information which is quite a valuable information for the energy producing companies.

Wireless and Density based Traffic Signal Light

The project is designed to develop a density based dynamic traffic signal system. The signal timing changes automatically on sensing the traffic density at the junction. Also system involves a wireless Bluetooth technologies for controlling the traffic lights from remote phone at the time of any emergency or unexpected situation. Traffic congestion is a severe problem in many major cities across the world and it has become a nightmare for the commuters in these cities.

Conventional traffic light system is based on fixed time concept allotted to each side of the junction which cannot be varied as per varying traffic density. Junction timings allotted are fixed. Sometimes higher traffic density at one side of the junction demands longer green time as compared to standard allotted time. The proposed system using a microcontroller of AVR family duly interfaced with sensors, changes the junction timing automatically to accommodate movement of vehicles smoothly avoiding unnecessary waiting time at the junction. The sensors used in this project are IR and photodiodes are in line of sight configuration across the loads to detect the density at the traffic signal. The density of the vehicles is measured in three zones i.e., low, medium, high based on which timings are allotted accordingly.

There is a Bluetooth module connected to the microcontroller for wireless remote operating traffic lights from android application operated remote mobile or PC. In any emergencies and unexpected situation the traffic lights signal can be operated according to the traffic situation by authorised person from remote phone or PC.