Electrical and electronics latest seminars



EEE&ECE LATEST SEMINARS:


‘Cling-Film’ Solar Cells – A New Revolution for Renewable Energy




Scientists from the Universities of Sheffield and Cambridge have started a new research that promises to produce cost-effective and highly efficient cling film solar cells. The idea was first published in the journal “Advanced Energy Materials”. According to them, these solar cells can also be produced with much ease. This has clearly become a great advancement in the field of renewable solar energy.
To carry out the tests, the ISI Neutron Source and Diamond Light Source at STFC Rutherford Appleton Laboratory in Oxfordshire were used.
Until now, two types of solar cell materials are being used – plastic and silicon. When it comes to manufacturing of the material, plastic is known to be much much cheaper. Due to the simple manufacturing process, they can also be produced in huge quantities. When molecules having complex mixtures are spread on to a surface, the molecules move away from one another and start to accumulate at the top and bottom of the layer. Thus, a highly efficient solar cell is produced. This same principle was used by researchers to prove that by using much better and cost less manufacturing methods, where flexible layers of material are deposited over large areas like cling-film, highly efficient solar cell structures can be produced.
These solar cells are known to be useful for both home use as well as industrial use and since it is very cheap, it can be manufactured on a high-scale. Instead of using high-end fabrication methods to manufacture a certain semi-conductor nanostructure, high number of printing could be used to produce nano-scale films of solar cells that are much thinner than the width of a human hair. Such films can be used to produce cost-effective, light-weight solar cell panels.
According to Dr. Robert Dalgliesh, one of the researchers of the project, the work makes us understand the potential of the joint use of neutron and X-ray scattering sources such as ISIS and Diamond in solving modern challenges for society. Using such sources help in making a stronger internal structure for the solar cell. By studying the layers in the solar cell that is responsible in converting sunlight into electricity, the different processing steps that change the overall efficiency and affect the overall polymer solar cell performance is also known.
Since most of the energy consumed today is through non-renewable sources, the demand for something that generates energy through a renewable source like the Sun is needed for the coming years. Since no highly efficient system that is capable of converting sunlight into electricity has been found until now, the cling-film solar cell will clearly pave way for the new age of renewable energy
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ECE LATEST SEMINAR TOPICS

ELECTRONICS LATEST SEMINARS:  PIR Sensor Based Security System


The circuit of an inexpensive and highly secure electronic security system is explained below. This electronic security system can be used in banks and other high security areas.
A normal electronic security system will have a transmitter and a receiver. The transmitter sends out an IR laser and this will be received by the receiver. When an intruder walks past the device, the IR beam is cut and thus the alarm is activated. But, this system has some major disadvantages like limited range and poor line of sight. These disadvantages are eliminated through the PIR sensor circuit explained below.

Working

Instead of infrared or laser transmitters and receivers, PIR (Passive Infrared Radial) sensors are used in this circuit. The sensor is basically a pyroelectric device. When the device is exposed to infrared radiation, it generates an electric charge. The device is made of crystalline material. According to the change in the amount of infrared striking the element, there will be a change in the voltages generated, which is measured by an on-board amplifier.
The infrared light explained here refers to the light radiating from all objects in its field of view. The reason for not having a transmitter and receiver is that the device does not emit one, but only accepts the energy emitted from objects above absolute zero in the form of radiations. Thus the temperature will be different for a human working past a sensor, and that of a wall right in front of it. Thus the word “passive” is used in PIR to explain that it does not emit a radiation and receive it, but instead accepts the incoming infrared radiation passively.

The block diagram of the PIR based security system is given below.





The device contains a special filter called a Fresnel lens, which focuses the infrared signals onto the element. As the ambient infrared signals change rapidly, the on-board amplifier trips the output to indicate motion. We can say that the PIR sensor is a human body sensor because it is only activated when a human or animal walks past the sensor. The PIR sensor is the heart of the project. We can design the project in such a manner that as soon as the burglar or intruder walks past the sensor, the alarms would turn on and the whole lighting system could turn on.

Circuit Diagram




  • PIR Sensor
D204B PIR sensor is used in this project. The PIR sensor is the heart of the project.
  • Two Stage Amplifiers
Two stage OP-amp: LM 324 is used as two stage amplifier. The signal from the PIR sensor is very low so this signal is amplified by using LM324.LM324 is a quad OP-amp. First two op-amps act as amplifiers.
  • Comparator
The comparator compares the signal from the amplifier and a reference voltage.3rd and 4th OP-amp of LM 324 act as comparator.
  • Transistor Switch
Whenever the output of comparator make HIGH Q1 transistor gets ON and relay will be energized causing the alarm and lamp to turn ON.
  • Power Supply
Power supply converts 230 Volt AC into 12 Volt DC and 5 Volt DC. IC 7812 is used as the 12 Volt voltage regulator and a 5v zener diode act as the 5 Volt voltage regulator









ECE SEMINAR TOPICS

ECE SEMINAR TOPICS: smart dust

INTRODUCTION
The current ultramodern technologies are focusing on automation
and miniaturization. The decreasing computing device size, increased
connectivity and enhanced interaction with the physical world have
characterized computing’s history. Recently, the popularity of small
computing devices, such as hand held computers and cell phones; rapidly
flourishing internet group and the diminishing size and cost of sensors and
especially transistors have accelerated these strengths. The emergence of
small computing elements, with sporadic connectivity and increased
interaction with the environment, provides enriched opportunities to
reshape interactions between people and computers and spur ubiquitous
computing researches.
Smart dust is tiny electronic devices designed to capture mountains
of information about their surroundings while literally floating on air.
Nowadays, sensors, computers and communicators are shrinking down to
ridiculously small sizes. If all of these are packed into a single tiny device,
it can open up new dimensions in the field of communications.
The idea behind ‘smart dust’ is to pack sophisticated sensors, tiny
computers and wireless communicators in to a cubic-millimeter mote to
form the basis of integrated, massively distributed sensor networks. They
will be light enough to remain suspended in air for hours. As the motes
drift on wind, they can monitor the environment for light, sound,
temperature, chemical composition and a wide range of other information,
and beam that data back to the base station, miles away.