WiTricity' system charges gadgets wirelessly from up to eight feet away - and could be in phones and tablets

WiTricity' system charges gadgets wirelessly from up to eight feet away - and could be in phones and tablets this year

Imagine a day when you can power your personal electronic devices without ever plugging them in?That will soon be a reality thanks to Witricity. The Watertown-based company creates wirelesss energy by using non-radiative magnetic fields to transfer energy. This infographic should help you understand how energy is transfered without using any wires.

 WiTricity Corp. technology will be the medium that ties our existing electric grid to a broad range of mobile and wireless devices—and enables the development of radically new and improved consumer, commercial, and industrial devices. WiTricity Corp. is now actively developing the core technology and additional intellectual property that will take this spectacular invention and turn it into commercially available products. Our mission is to develop a family of wireless power components that will enable designers and manufacturers in a broad range of industries to make their products truly “wireless”.


The technology, which will start appearing in gadgets from later this year, could also be used for tablets and small games consoles.
The American company behind it hopes that gadget companies will make special batteries with receiver coils to work with the system - or gadgets such as vacuum cleaners built to work wirelessly. 
And in the future the researchers believe they may be able to charge electronic cars and even heart pumps via a similar connection.

This only works within a short distance however because the primary coil is not that strong.
WiTricity expands this principle using a wireless connection so that it works up to several feet away, and perhaps even further.
The company has signed a deal with a semiconductor company in Taiwan to produce the coils, although the components will not be made available to the public.
If WiTricity is used by phone makers it will remove the pain of having to charge your mobile in public.
Douglas Stone, chairman of the Department of Applied Physics at Yale, said that technology had come along just at the right time.
He said: ‘The difference in what you can do when you charge at a very short range - essentially contact - and when you can do it at a meter or two, is huge’.

WiTricity’s technology can be used to power everything from your TV, cellphone, electric car and even medical devices.
Yinon Weiss, Director of Product Marketing for Witricity, told New England Post, they don’t plan on eliminating power lines, but they do plan on eliminating power cords.

 

     Currently they have 30 employees but plan on expanding next year.

Weiss says their business model is to enable companies to use Witricity technology. The company is in the process of licensing its technology for a wide field of use, building partnerships with major consumer electronics companies, car manufacturers, and medical device companies.

Understanding what WiTricity technology is—transferring electric energy or power over distance without wires—is quite simple. Understanding how it works is a bit more involved, but it doesn’t require an engineering degree. We’ll start with the basics of electricity and magnetism, and work our way up to the WiTricity technology.

Electricity: The flow of electrons (current) through a conductor (like a wire), or charges through the atmosphere (like lightning).  A convenient way for energy to get from one place to another!

An illustration representing the earth's magnetic field

Electromagnetism:  A term for the interdependence of time-varying electric and magnetic fields. For example, it turns out that an oscillating magnetic field produces an electric field and an oscillating electric field produces a magnetic field.
Magnetic Induction: A loop or coil of conductive material like copper, carrying an alternating current (AC), is a very efficient structure for generating or capturing a magnetic field.

If a conductive loop is connected to an AC power source, it will generate an oscillating magnetic field in the vicinity of the loop.  A second conducting loop, brought close enough to the first, may “capture” some portion of that oscillating magnetic field, which in turn, generates or induces an electric current in the second coil. The current generated in the second coil may be used to power devices. This type of electrical power transfer from one loop or coil to another is well known and referred to as magnetic induction. Some common examples of devices based on magnetic induction are electric transformers and electric generators.

Energy/Power Coupling:  Energy coupling occurs when an energy source has a means of transferring energy to another object. One simple example is a locomotive pulling a train car—the mechanical coupling between the two enables the locomotive to pull the train, and overcome the forces of friction and inertia that keep the train still—and, the train moves. Magnetic coupling occurs when the magnetic field of one object

An electric transformer is a device that uses magnetic induction to transfer energy from its primary winding to its secondary winding, without the windings being connected to each other. It is used to “transform” AC current at one voltage to AC current at a different voltage.

interacts with a second object and induces an electric current in or on that object. In this way, electric energy can be transferred from a power source to a powered device. In contrast to the example of mechanical coupling given for the train, magnetic coupling does not require any physical contact between the object generating the energy and the object receiving or capturing that energy.

Resonance

Resonance: Resonance is a property that exists in many different physical systems. It can be thought of as the natural frequency at which energy can most efficiently be added to an oscillating system. A playground swing is an example of an oscillating system involving potential energy and kinetic energy. The child swings back and forth at a rate that is determined by the length of the swing. 

The child can make the swing go higher if she properly coordinates her arm and leg action with the motion of the swing. The swing is oscillating at its resonant frequency and the simple movements of the child efficiently transfer energy to the system. Another example of resonance is the way in which a singer can shatter a wine glass by singing a single loud, clear note. In this example, the wine glass is the resonant oscillating system. Sound waves traveling through the air are captured by the glass, and the sound energy is converted to mechanical vibrations of the glass itself.  When the singer hits the note that matches the resonant frequency of the glass, the glass absorbs energy, begins vibrating, and can eventually even shatter. The resonant frequency of the glass depends on the size, shape, thickness of the glass, and how much wine is in it.

Resonant Magnetic Coupling: Magnetic coupling occurs when two objects exchange energy through their varying or oscillating magnetic fields. Resonant coupling occurs when the natural frequencies of the two objects are approximately the same.

Two idealized resonant magnetic coils, shown in yellow. The blue and red color bands illustrate their magnetic fields. The coupling of their respective magnetic fields is indicated by the connection of the colorbands.

WiTricity Technology: WiTricity power sources and capture devices are specially designed magnetic resonators that efficiently transfer power over large distances via the magnetic near-field. These proprietary source and device designs and the electronic systems that control them support efficient energy transfer over distances that are many times the size of the sources/devices themselves.

The WiTricity power source, left, is connected to AC power. The blue lines represent the magnetic near field induced by the power source. The yellow lines represent the flow of energy from the source to the WiTicity capture coil, which is shown powering a light bulb. Note that this diagram also shows how the magnetic field (blue lines) can wrap around a conductive obstacle between the power source and the capture device.

Why you should continuously improve your soft skills

Why you should continuously improve your soft skills....

 In India, electronics engineering as a career has always attracted the student community in a big way. Testimony to this fact is an ever-increasing number of aspirants taking various entrance exams to qualify and enroll for their choice of engineering branch. Throughout the course, one learns and specialises in a particular branch of engineering theoretically and practically. However, just technical skills are not enough as the most common HR question is: Beyond technical skills, experience and knowledge, what added value do you bring to the organisation? Therefore soft skills are critical to make you employable.

Role of Soft Skills in your Engineering Career

 The most common Hr question is: Beyond technical skills, experience and knowledge, what added value do you bring to the organisation? Of course, it is the soft skills that ensure success in your career. Here is what exactly are soft skills, why they are needed and what you can do to improve your soft skills.

 

 What exactly are soft skills?
Naresh Narasimhan, country marketing manager, Tektronix, says, “In the 21st century and going forward, three things are important—ability to communicate an idea visually, ability to have a balanced point-of-view on key issues and ability to convert ideas to results.”

The concept of soft skills is not limited to just plain communication skills but it also includes aspects such as people skills.

Dr Pallab Bandyopadhyay, director-HR, Citrix India, explains: “In the broader context, soft skills would also include negotiation, decision making, reasoning and problem solving, and conflict-resolution skills required in today’s work environment.”

“While technical professionals are often selected and trained based on measurable talents and skills such as knowledge of OS or software programming skills—which are prerequisites to starting a career in engineering and technology—intangible skills such as language proficiency, ability to work with global teams and positive attitude often count in making their career a rewarding one. These intangible skills are classified as soft-skills,” adds Sudhanshu Pandit, director-HR, Symantec India.

When evaluating a candidate on soft skills, HR professionals look at not only his ability to communicate his thoughts clearly and concisely but also his personality and problem-solving skills.

Defining soft skills, John Prohod-sky, founder and principal consultant, Future Envisioned, says, “Soft skills are non-technical, interpersonal and communication skills required by an engineer to successfully solve problems and apply his technical skills.”

Throwing light on how soft skills are directly proportional to one’s personality, Rajesh Choudhary, HR head, Xilinx India, says, “Personality traits such as common sense, optimism, responsibility, integrity, attitude and behavioural competencies that include analytical thinking, result orientation and achievement, communication, teamwork, conflict management, customer orientation and attention to details come under soft skills.”

As soft skills cover all the aspects related to human behaviour, Zubin Rashid, managing partner and head of training, ZRINDIA, believes that “Just as hard skills teach us about domain-specific skills like technology, products and processes, soft skills are about interacting with people with whom you work.”

Every company looks for a different mix of skills and experience and it is not enough just to be a subject matter expert. Communication is an integral part of soft skills.

Surinder Bhagat, country HR head, Freescale Semiconductor, India, says, “Soft skills can also refer to a set of skills that determine how one interacts with others in a way that the company as such gets represented well. These skills are applicable to all internal as well as external forums where employees are making key interactions.”

Tina Vas, vice president-global HR, Collabera, says “Simply put, soft skills have more to do with who we are than what we know.”

Soft skills critically impact the way an individual translates his expertise across to his team and further to the whole organisation.

Ramana Vemuri, VP-process and operations, Cigniti Technologies, believes that soft skills enhance an individual’s interactions, job performance and career prospects. According to him, emotional intelligence is the critical element that defines the core of soft skills a person is equipped with.

Soft skills in today’s India

 
According to a recent report by employability assessment company Aspiring Minds, 56 per cent engineering graduates in India lack soft skills and cognitive skills. Non-technical aspects of engineering such as communications, relationships, temperament, emotional intelligence and risk management make a difference between success and failure. Understanding and adapting to the working environment is just as crucial as getting the job itself.

Prohodsky says, “Engineering is the application of hard sciences to solve real problems but what they rarely teach in colleges is that engineering, in addition to being a technical activity, is an economic activity and, most importantly, a human activity.”

According to him, the ability to understand company and work team culture is the most under-appreciated soft skill.

Bhagat says, “As companies become more global, soft skills are highly desirable and required in more positions now than ten or even five years ago. You may have an excellent knowledge base in engineering or technology, perhaps even a PhD, and maybe bilingual but if you have not developed good skills in communicating, interacting and people resource management, you have already limited your opportunities and chance of success.”

Vas adds, “Networking is also important; engineers need to keep in touch with alumni as well as industry experts via various interactive forums to understand the ground realities better.”

Why you should continuously improve your soft skills

 
“Soft skills are applied emotional intelligence and as such, they are very important. As engineers, we are taught to think and apply the logic of math and science. However, we are being ruled by emotions,” says Prohodsky.

Soft skills are very essential for personal and professional development of individuals. “In today’s economy, it is even more important considering a significant portion of Indian GDP comes from services sector. To support this growth in services sector, organisations require talents who possess greater soft skills along with hard skills,” notes Rajesh Choudhary.

“Technical skills may take you to the doorstep but it is your soft skills that will open up the door for you,” believes Dr Pallab.

Adding on the growing importance of soft skills in today’s world, Vemuri says, “They (soft skills) are in demand than ever. Increasing possibility of interactions with global peers, customers, virtual teams and cross-cultural discussions mandate employers to look out for fine-tuned, polished workforce.”

“Soft skills facilitate efficiency and effectiveness at work,” says Sunil Pathak, HR director, Cadence Design Systems. While flawless technical expertise is the primary necessity, soft skills are imperative to ensure high-quality contribution and delivery.

Pandit explains, “An engineer might be excellent at writing code to solve a particular problem but unless he possesses soft skills, he would neither be able to understand the problem faced by a customer nor explain how his suggested method makes the best fitted solution for the customer’s problem.”

Dr Pallab believes that soft skills are as important as technical skills due to two main factors: “One is that employees are being sent on projects to international locations, where they need to articulate their thoughts and actions to become productive. Second, with enhanced globalisation, virtual communication has taken a front seat in today’s organisations.”

An engineer is rewarded for his ability to make decisions, manage risks and creativity. Therefore soft skills are vital for an individual to get employed and grow in an organisation.

Myth Buster

Myth 1: It is the hard skills (technical skills) that get you a job, not soft skills.Truth: You need to balance both. Myth 2: Being strong in analytical aptitude, quantitative expertise and information-gathering ability is enough to fetch a job. Truth: In addition to the above, you need strategic thinking, written and oral communication skills, leadership skills, and adaptability.

A ‘soft skills’ survey

Recently, EFY conducted an opinion survey of engineering students, fresh professionals and industry analysts through various social media platforms to understand the importance of soft skills, apart from tech knowhow, for a successful career. 62.63 per cent respondents believed that soft skills were important but not the deciding factor. 25.29 per cent believed that soft skills were extremely important. Remaining 12.08 per cent believed that these were important as complementary skills. EFY Survey results on soft skills across various social media platforms

Hard skills vs soft skills— what you should focus on
Let’s take the example of software engineers. They need to be skilled in software development and testing to be able to build, test and provide support for the applications developed by them. However, to do that successfully, they need to work in a team and interact with team members to provide the best products and services. Any misunderstanding or strife between team members would result in products and services that would not be of the highest standards. Computer programming in many languages is a hard skill, whereas problem solving and communication are soft skills.

 

 

 

V2G-Vehicle-to-Grid --

Green Technology.

Vehicle-to-Grid Technology.

 

Electric Car Networks Represent Another Energy Storage Solution.

 Right after reading Brian Albright’s piece “Energy Storage Solution Full of Hot Air,” I came across an interesting energy solution in a Scientific American blog post by Lesley Evans Ogden. This article discusses the history and commercialization of vehicle-to-grid technology  (V2G), which was developed by Willett Kempton at the University of Delaware along with Vermont’s Green Mountain College economist Steve Letendre. The concept is to create a network of electric vehicles (EV) to act as batteries, charging the EVs’ batteries during slow energy usage times and feeding the energy back to the grid during high demand.

 

This would be extremely useful in micro-grid applications and in applications using solar and wind energy generation.  Professor Kempton sold his rights to this technology to Danish company Nuvve last June. They, in turn, have licensed NRG Energy of New Jersey to develop this concept in the U.S. This service will initially be implemented to large fleet owners of EVs but could be rolled out to individuals as early as 2015.

The upside of this program is not just in the pockets of the large energy producers, who will have more control over regulating energy generation and distribution, but to the car owners, who stand to make as much $10,000 over the lifetime of their electric vehicle. The downside, battery life can be shortened because of more discharge and charging cycles. Still, a pretty cool idea that is being piloted right now.

When one sees the term G2V it is understood to refer to the normal process of using the electric grid to charge the battery of an electric vehicle. V2G however is better understood as using the battery as a source of electric energy. The discharge of the battery to generate electricity may or may not have a connection to the grid. There are a variety of applications for the technology; Vehicle-to-House (V2H), Vehicle-to-Building (V2B), and, of course, V2G.

Built from a 2006 Scion xB that was stripped of its internal-combustion engine and related systems, the eBox uses a drive system consisting of an ac induction motor, inverter, bidirectional charger, and battery management system. Capable of 0-60 mph (97 km/h) in 7 s, the eBox has a top speed of 95 mph (153 km/h), energy consumption of 220 to 320 W·h/mi (354 to 515 W·h/km), and driving range of 100 to 145 mi (161 to 233 km).

With 5088 cylindrical cells, the eBox's lithium-ion battery pack has 32 usable kW·h at a nominal charge of 345 V. The eBox's drive system provides 120 kW of propulsion power and up to 18 kW of charging power. 

In the summer of 2011, DTU researchers took delivery of an eBox to further their V2G research efforts. 

According to Peter Bach Andersen, a Ph.D. student involved with V2G research at DTU's Centre For Electric Technology (CET), ongoing investigations at the center include grid impact studies to determine how the electrical power distribution system handles the power consumption needs of EVs, as well as smart charging scenarios in which the timing of an EV's recharging is based on energy costs, grid capacity, and other factors.

"While DTU has done some EV research before, it has never been with a V2G-capable EV. The eBox is one of the first EVs in Denmark to have this capability," Bach Andersen told AEI. 

Denmark's offshore wind farms will factor into CET's V2G research tasks.

EV charging will be indirectly linked to wind production via the energy market. If a lot of wind energy is available during certain hours, the energy cost will be lower and the EV will choose to charge at those hours. 

 

"Smart charging should, in general, support better utilization of wind energy," said Andersen. "And V2G can move this EV/wind synergy even further by delivering stored wind energy back to the grid at later times. Future power markets will most likely facilitate a tighter link between EVs and wind."

 

Maximising Solar PV Energy Penetration

Maximising Solar PV Energy Penetration.

The technology challenge in PV will be to generate innovations in efficiency and cost reduction fast enough to maintain a profit margin.

 

Photovoltaics (PVs) will be a key pillar of our future sustainable energy system, and 1:1:1 for wind, solar, and others (hydro, biomass, geothermal) is a reasonable expectation—according to Prof. Eicke R. Weber, director of the Fraunhofer Institute for Solar Energy Systems ISE, and professor for physics/solar energy at the Faculty of Mathematics and Physics and at the Faculty of Engineering at the Albert-Ludwigs-University of Freiburg, Germany.

Crystalline silicon will remain the dominant PV technology. Classical thin-filmhas to show lower prices or comparable efficiencies. Highly-efficient concentrated photovoltaics (CPVs) will take up a rapidly increasing niche market, competing with concentrating solar power (CSP).





Prof. Weber, along with S. Janz and S. Glunz from the Fraunhofer-Institute for Solar Energy Systems ISE and Albert-Ludwigs, University, Freiburg, Germany, presented his thoughts on ‘Photovoltaics: Pillar of our Future Sustainable Energy System,’ at the recently held Intersolar Europe 2012 in Munich, Germany.

The technology challenge in PV will be to generate innovations in efficiency and cost reduction fast enough to maintain a profitmargin; only players in the XGW-range will survive in the long term. State support for investments in XGW plants, e.g., credit guarantees, might be necessary to maintain globally a level-playing field for PV production.

Creating market barriers will lead to higher prices and less pressure for cost reduction and innovation, ultimately hurting the economies that adopt them.

Bright future for PV
Globally, the required power is 16 TW today, and it will reach at least 30 TW by 2050. PV is offering at least 10 per cent of this requirement. Optimistically, it should meet 30-40 per cent of the global energy needs. 3TW power corresponds to 12 TW or 12,000 GW of PV capacity.



PV capacity globally installed till 2009 was 20 GW. It was +17 GW in 2010 and increased to +25 GW in 2011. To reach 12,000 GW, we would need almost 500 years at this rate! The PV market will move from a $50-billion market to hundreds of billion dollars in a few years. This will be accompanied by a drastic cost reduction, making PV one of the most inexpensive ways to produce energy, in the range of 5 cts/kWh, comparable with hydro and onshore wind but less than nuclear and fossil fuels by 2030 or earlier!

For a 100 per cent renewable energy scenario, at least three components or technologies are required in a ratio of 1:1:1. These are solar energy (PV and solar thermal), wind and hydro, and geothermal and biomass.

The maximal sum of PV and wind production was 7.6 TWh in January 2012. The minimal sum was 5.6 TWh in February 2012. The total annual electricity need of Germany is about 600 TWh. The global market forecast is said to be 30 GW in 2014 and 110 GW in 2020. The annual growth rate should be in the range of 20-30 per cent.

If you look at the global PV production development by technology, by 2011, thin filmhad accounted for 3204 MWp, ribbon-Si 120 MWp, multi-Si 10,336 MWp and mono-Si 9114 MWp, respectively.

Efficiencies in the solar cell market
Efficienciesin the solar cell market range from 1 to 5  per cent for organic, dye and nanostructure cells. PV technologies of interest in the next one to two decades are:
1. 6-11 per cent: Thin-film cells (a-Si, microcrystalline-Si, CIS, CIGS, CdTe)
2. 14-18 per cent: mc-Si, umg-Si, simple c-Si cells
3. 20-24 per cent: High-efficiencyc-Si cells
4. 36-41.1 per cent: High-efficiencyIII/V tandem cells for concentrators with 25-30 per cent module efficienc

The price learning curve for all c-Si PV technologies indicated that with each doubling of cumulative production, price went down by 20 per cent. So thin-filmtechnologies must ramp up fast enough to maintain a clear cost advantage at lower efficiencies!

Prof. Weber cited examples: Solar cells built with 100 per cent umg-Si have a conversion efficiencyof less than 20 per cent. Silicor plans a umg-Si plant with a capacity of 16,000 tpa at a cap-ex of $600 million. The median efficiencyat CaliSolar is now 16.6 per cent. At least 11 per cent of the cells have a conversion efficiencyof above 17 per cent with the highest at 17.7 per cent. Q-cells has achieved 18.2 per cent efficiencyusing umg-Si cell with backside contacts.

The advantages and future requirements for mc-Si include a mature process and no scalability limit. Quality needs to be high enough for 20 per cent efficien solar cells. Diffusion length should be greater than 500 μm at cell thickness of 150 μm. Impurities should exhibit low activity/good gettering behaviour. There should be monocrystals, leading to easy texturing. Some other requirements include increase of yield (less low-quality areas), processes for umg-Si feedstock and cost below 0.30/Wp.

Creating market barriers will lead to higher prices and less pressure for cost reduction and innovation, ultimately hurting the economies that adopt them

 
Prof. Weber gave another example of a high-quality block-crystallised silicon material. There should be polarity switch in umg silicon. The umg Si is compensated: both boron (B) and phosphorous (P) are present in the feedstock. The dopant crossover is due to different segregation coefficients.The consequence: p- and n-type Si within the same brick and even single wafers. Dopant engineering is needed to avoid the p-n switch or increase the yield.

There is another example: non-conventional c-Si material or solar cells made from crystalline silicon thin-films. All concepts have good to very good cost perspective. High-throughput, low-cost Si deposition will be required for quick progress.

The key design data of a non-conventional c-Si material (ProConCVD) was presented. The ProConCVD is a massively scaled version of the ConCVD, intended to prove the scalability of the approach to a near-production level of more than a thousand wafers per hour. The data includes:
1. Three tracks, each with two car-riers. Each carrier holds three 156×156 mm2 wafers in height
2.  Total deposition area: 5 m2
3. Maximum transport speed: 12 m/h
4. Furnace: max. 360kW, resistance-heated, 2x8m2 footprint, 2m stable zone
5. Process temperature up to 1300°C
6. Available process gases (maximum consumption/min): SiHCl3 (300 gm), SiCl4 (500 gm), SiCl3(CH3) (300 gm), H2 (4000 sl), HCl (50 sl)
7. Throughput > 30 m2/h (equivalent to 1200 wafers per hour) for 20μm layer thickness. A simple scale-up is possible.

As per the current status of ProConCVD, all hardware installations have been completed. The transport and heating system is in operation. The infrastructure is online. The firsthigh-quality epitaxial layers have been done successfully. Strategies to increase the efficiency o normal crystalline silicon solar cells include advanced metallisation, selective emitters, dielectric surface passivation, thinner wafers, process control, ultra-light trapping, material quality and back-contact cells. Estimating the efficiencypotential on boron-doped Cz-Si, with a limitation due to metastable boron-oxygen defect, there is the optimised industrial cell structure (PERL). The efficiencyis limited to about 20 per cent due to boron oxygen lifetime degradation. The solution: n-type silicon, with no degradation and higher tolerance to metal contamination.

The lab results of high-efficiency n-type PERL cells were also shared. There was substitution of local phosphorus diffusion by laser doping from innovative double-function PassDop layer (passivation and doping). Excellent results were achieved with evaporated front contacts.
 

Prof. Weber talked about the efficiencies of Ni/CuSn metallisation. Solar cell properties include direct plating, lowly doped emitter (120 ohms/square) and dielectric rear passivation. It also has excellent efficiecies and fillfactors. As for the thin-filmCIS solar cell structure, the key challenge is to realise the impressive small-area lab effciency results in production-size modules and volume production.

He touched upon the benefits of multi-junction sola cells and high-efficiencyISE triple-junction solar cells obtained by MOCVD thin-filmdeposition. Advantages of high-concentration PV cells include system effiiencies of 25 per cent AC today, about 200 MW/year worldwide production capacity, no cooling water or intentional hot water, modular kW to GW scale, and one-year energy payback time.

The future vision: Renewable electricity super grid
Prof. Weber gave an example of DESERTEC—the vision of an electricity super grid. DESERTEC is a mega renewable energy project that aims to set up a massive network of solar and wind farms stretching across the Middle East and North Africa (MENA) region and connected to Europe via a Euro-Mediterranean electricity network made up of high-voltage direct current transmission cables. The project, estimated at €400 billion, will provide 15 per cent of Europe’s electricity by 2050. 

Build a Simple Laser Interferometer in 10 Minutes

An interferometer is a device that makes light waves interfere with one another. Depending on how it is set up, it can be used to measure distances with extreme accuracy (less than a wavelength of light).

We can build one in a few minutes to demonstrate the effect, using a pocket laser pointer, a solar cell, and a mirror.

While we do sell solar cells in our catalog, in this project I am going to show you how to get one for free out of a cheap solar powered calculator. I say for free because although the calculator I used cost $6, it is still functional after I removed the solar cell. It just depends on its internal battery (until I decide to put the solar cell back in).

The back of this calculator had a single screw, that once removed, allowed me to snap the cover off of the calculator. The solar cell was held in place with a thin line of rubber cement. I lifted the solar cell away from the plastic by gently prying it off with a knife.

You can use a soldering iron to remove the solar cell wires, or you can just cut them.

The photo above shows how the interferometer is set up. I used a plastic case to hold the solar cell in place just above the laser beam. This allows the solar cell to catch some of the beam after it is reflected by the mirror. Most of the beam is directed by the mirror straight back into the laser. A binder clip holds the laser in place, and at the same time holds down the ON button.

The solar cell is connected to a small amplifier (you can get these at Radio Shack). You can also use the microphone input of a stereo or boom box, or of your computer.

The laser in a pocket laser pointers has two flat edges that act as mirrors, bouncing the light back and forth between them. As the light moves back and forth through the laser chip, the chip is able to add a little energy to the beam each time is passed through. This amplifies the light. Some of the light gets through the end of the chip (since the mirror is not perfectly opaque), and we get a beam of light.

The big mirror becomes part of the laser when it redirects the beam back into the laser. The path between the laser and the big mirror includes the laser chip, and the light gets amplified a little more.

But the light also interferes with itself. Where the waves are in phase, they are brighter than normal, and if they are out of phase, they dim to almost complete darkness. This makes bands of light and dark, like zebra stripes. Some of those stripes strike the solar cell, and generate electricity to make the speaker move.

By gently tapping on the mirror, we can make it move. This changes the patter of stripes, and makes a whistling shriek in the speaker as the lines move across the solar cell. The pitch of the squeal tells us how fast the mirror is moving.

 

Hy-wire -Best car ever engineered _ The green car _ The future car

Hy-wire

  The HY WIRE concept car the name symbolizes the combination of hydrogen as fuel for the fuel cell propulsion system, and the replacement of conventional mechanical and hydraulic control linkages for steering, braking and other control systems by a drive-by-wire system. By combining fuel cell and by-wire technology, General motors have packaged this vehicle in a new way, opening up a new world of chassis architectures and customized bodies for individualized expressions and it is a significant step towards a new kind of automobile that is substantially more friendly to the environment and provides consumers positive benefits in driving dynamics, safety and freedom of individual expression.

 

The world today consumes a large amount of energy. Most of the energy requirements are fulfilled using conventional sources of energy. Of this energy consumed, a large part is utilized by the automotive sector. If the people continue using the conventional sources of energy at this rate, the earth will be facing an energy crisis very soon. The introduction of an efficient electric vehicle can greatly improve the conditions of today by helping curb the use of traditional fuels.

 

The Hy-Wire, discussed in this paper, runs on the electricity generated by a hydrogen fuel cell, more accurately called the 'Proton Exchange Membrane' fuel cell. This fuel cell uses hydrogen as a source of fuel. The fuel cell produces dc voltage, which is converted to ac voltage and used to run an ac motor.

The by-wire concept removes the mechanical linkages and replaces all of them by wires and electromechanical actuators. This makes the whole vehicle lighter and more spacious. In the Hy-Wire vehicle, the whole system has been modeled into an 11-inch thick chassis. This chassis houses all the electrical components and mechanical components of the vehicle. This lets us make the body in a customized version and also lets us change the chassis architecture with radical new designs.

The by-wire system is made practical by the higher voltages inherent in a fuel cell system. The 42-V technology is made use of in this vehicle. It is said to be a luxury car in the sense that it provides the space and visibility that a luxury car does.

Control

The Hy-wire's "brain" is a central computer housed in the middle of the chassis. It sends electronic signals to the motor control unit to vary the speed, the steering mechanism to maneuver the car, and the braking system to slow the car down.

 

At the chassis level, the computer controls all aspects of driving and power use. But it takes its orders from a higher power -- namely, the driver in the car body. The computer connects to the body's electronics through a single universal docking port. This central port works the same basic way as a USB port on a personal computer: It transmits a constant stream of electronic command signals from the car controller to the central computer, as well as feedback signals from the computer to the controller. Additionally, it provides the electric power needed to operate all of the body's onboard electronics. Ten physical linkages lock the body to the chassis structure.

 

 

 

The Hy-wire's X-drive The X-drive can slide to either side of the vehicle.

Photo courtesy General Motors Photo courtesy General Motors

 

 

 

The Hy-wire's X-drive The X-drive can slide to either side of the vehicle.

Photo courtesy General Motors Photo courtesy General Motors

The driver's control unit, dubbed the X-drive, is a lot closer to a video game controller than a conventional steering wheel and pedal arrangement. The controller has two ergonomic grips, positioned to the left and right of a small LCD monitor. To steer the car, you glide the grips up and down lightly -- you don't have to keep rotating a wheel to turn, you just have to hold the grip in the turning position. To accelerate, you turn either grip, in the same way you would turn the throttle on a motorcycle; and to brake, you squeeze either grip.


Electronic motion sensors, similar to the ones in high-end computer joysticks, translate this motion into a digital signal the central computer can recognize. Buttons on the controller let you switch easily from neutral to drive to reverse, and a starter button turns the car on. Since absolutely everything is hand-controlled, you can do whatever you want with your feet (imagine sticking them in a massager during the drive to and from work every day).


The 5.8-inch (14.7-cm) color monitor in the center of the controller displays all the stuff you'd normally find on the dashboard (speed, mileage, fuel level). It also gives you rear-view images from video cameras on the sides and back of the car, in place of conventional mirrors. A second monitor, on a console beside the driver, shows you stereo, climate control and navigation information.


Since it doesn't directly drive any part of the car, the X-drive could really go anywhere in the passenger compartment. In the current Hy-wire sedan model, the X-drive swings around to either of the front two seats, so you can switch drivers without even getting up. It's also easy to adjust the X-drive up or down to improve driver comfort, or to move it out of the way completely when you're not driving.

 

 

 

GM concept of the AUTOnomy with and without a body attached

Photo courtesy General Motors Photo courtesy General Motors

 

 

 

GM concept of the AUTOnomy with and without a body attached

Photo courtesy General Motors Photo courtesy General Motors

One of the coolest things about the drive-by-wire system is that you can fine-tune vehicle handling without changing anything in the car's mechanical components -- all it takes to adjust the steering, accelerator or brake sensitivity is some new computer software. In future drive-by-wire vehicles, you will most likely be able to configure the controls exactly to your liking by pressing a few buttons, just like you might adjust the seat position in a car today. It would also be possible in this sort of system to store distinct control preferences for each driver in the family.


The big concern with drive-by-wire vehicles is safety. Since there is no physical connection between the driver and the car's mechanical elements, an electrical failure would mean total loss of control. In order to make this sort of system viable in the real world, drive-by-wire cars will need back-up power supplies and redundant electronic linkages. With adequate safety measures like this, there's no reason why drive-by-wire cars would be any more dangerous than conventional cars. In fact, a lot of designers think they'll be much safer, because the central computer will be able to monitor driver input. Another problem is adding adequate crash protection to the car.


The other major hurdle for this type of car is figuring out energy-efficient methods for producing, transporting and storing hydrogen for the onboard fuel-cell stacks. With the current state of technology, actually producing the hydrogen fuel can generate about as much pollution as using gasoline engines, and storage and distribution systems still have a long way to go (see How the Hydrogen Economy Works for more information).
So will we ever get the chance to buy a Hy-wire? General Motors says it fully intends to release a production version of the car in 2010, assuming it can resolve the major fuel and safety issues. But even if the Hy-wire team doesn't meet this goal, GM and other automakers are definitely planning to move beyond the conventional car sometime soon, toward a computerized, environmentally friendly alternative. In all likelihood, life on the highway will see some major changes within the next few decades.
For more information about the Hy-wire and other emerging automotive technologies, check out the links on the next page.

Hydrogen Fuel Cells

A fuel cell is an electrochemical energy conversion device. A fuel cell converts the hydrogen and oxygen into water and in the process produces electricity. Such fuel cells, which use hydrogen as a source of fuel, are called hydrogen fuel cells. The other electrochemical device that we are all familiar with is the battery. A battery has all of its chemicals stored inside, and it converts those chemicals into electricity too. This means that a battery eventually goes dead and you either throw it away or recharge it. With a fuel cell, chemicals constantly flow into the cell so it never goes dead - as long as there is a flow of chemicals into the cell, the electricity flows out of the cell.
Sir William Grove invented the first fuel cell in 1839. He used dilute sulphuric acid as electrolyte, oxygen as the oxidizing agent and hydrogen as fuel. In 1959, Francis T Bacon came up with an alkaline fuel cell, but it could produce only 5-kilowatt power.
A fuel cell produces dc voltage that can be used for various needs. The fuel cells are classified into various types depending upon the electrolyte they use. They are classified as follows: -
a) Direct method fuel cells
b) Solid oxide fuel cells
c) Phosphoric acid fuel cells
d) Alkaline fuel cells
e) Molten carbonate fuel cells.

 

Coolest things about the car.
Instead of an engine, it has a fuel cell stack, which powers an electric motor connected to the wheels.
Instead of mechanical and hydraulic linkages, it has a drive by wire system -- a computer actually operates the components that move the wheels, activate the brakes and so on, and based on input from an electronic controller. This is the same control system employed in modern fighter jets as well as many commercial planes.The result of these two substitutions is a very different type of car -- and a very different driving experience.
There is no steering wheel, there are no pedals and there is no engine compartment. In fact, every piece of equipment that actually moves the car along the road is housed in an 11-inch-thick (28 cm) aluminum chassis -- also known as the skateboard - at the base of the car. Everything above the chassis is dedicated solely to driver control and passenger comfort.This means the driver and passengers don't have to sit behind a mass of machinery.
Instead, the Hy-wire has a huge front windshield, which gives everybody a clear view of the road.
The floor of the fiberglass-and-steel passenger compartment can be totally flat, and it's easy to give every seat lots of leg room.
Concentrating the bulk of the vehicle in the bottom section of the car also improves safety because it makes the car much less likely to tip over.
But the coolest thing about this design is that it lets you remove the entire passenger compartment and replace it with a different one. If you want to switch from a van to a sports car, you don't need an entirely new car; you just need a new body (which is a lot cheaper).
The driver's control unit, dubbed the X-drive, is a lot closer to a video game controller than a conventional steering wheel and pedal arrangement. The controller has two ergonomic grips, positioned to the left and right of a small LCD monitor. To steer the car, you glide the grips up and down lightly -- you don't have to keep rotating a wheel to turn, you just have to hold the grip in the turning position. To accelerate, you turn either grip, in the same way you would turn the throttle on a motorcycle; and to brake, you squeeze either grip.
In the current Hy-wire sedan model, the X-drive swings around to either of the front two seats, so you can switch drivers without even getting up. It's also easy to adjust the X-drive up or down to improve driver comfort, or to move it out of the way completely when you're not driving.
It is environment friendly and the only product of the emission is drinkable water.

TECHNICAL SPECIFICATIONS

• Top speed                                         : 100 miles per hour (161 kph)

• Weight                                              : 4,185 pounds (1,898 kg)

• Chassis length                                   : 14 feet, 3 inches (4.3 meters)

• Chassis width                                    : 5 feet, 5.7 inches (1.67 meters)

• Chassis thickness                               :11 inches (28 cm)

• Wheels                                              : eight-spoke, light alloy wheels.

• Tires                                                 : 20-inch (51-cm) in front and 22-inch (56-cm) in 

                                                              back

• Fuel-cell power                                 : 94 kilowatts continuous, 129 kilowatts peak

• Fuel-cell-stack voltage                      : 125 to 200 volts

• Motor                                                : 250- to 380-volt three-phase asynchronous      

                                                                electric motor

• Crash protection                                : front and rear "crush zones" (or "crash boxes")

                                                               to absorb impact energy

• Related GM patents in progress          : 30

• GM team members involved in design : 500+

Make your own LED Resistor Selector Dial

Make your own LED Resistor Selector Dial.

  1.The theory behind the LED Resistor Selector Dial
 The Theory Behind this make

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LEDs are diodes with very specific characteristics. The most important values that must be followed are the (maximum) forward voltage [Vf] and the (maximum) forward current [If]. Typically, an LED powered with a voltage equal to Vf, will allow a current equal to If to pass through. The forward voltage of LEDs depends on the material they are made of (thus the color that they emit) and the number of diodes in series they have. For example, a red LED typically operates at 20mA when a voltage of 2.2 volts is applied across its leads.

 So, what happens if we have 5 volts to power this 2.2V LED? There are many different LED drivers, but the simplest one is to use a resistor in series. Here is the typical circuit:






The idea of the resistor is to generate a voltage drop across its leads. Byselecting this resistor properly, the voltage across the LED will be as much as required. To select the proper resistor value, we need first to know how much voltage we need to drop on this resistor. Suppose that the power supply has a voltage of 5 volts (Vdd) and the red LED needs 2.2 volts to operate at 20mA. The voltage across the resistor must then be:


V_RES = V_DD - VLED => V_RES = 5 - 2.2 => V_RES = 2.8 Volts


Now we can simply use the Ohm's law to calculate the resistor value. The idea is that we want a specific voltage drop (2.8 volts) at a specific current (20mA) (remember to convert the current to Amperes):


R = V_RES / If => R = 2.8 / 0.02 => R = 140 Ohms


So, the resistor will be 140 Ohms! When power is provided to the above circuit, the current will climb up to 20mA. At that point, the voltage across the resistor will be 2.8 volts, so the remaining voltage (2.2 Volts) will be applied to the LED.

One more important value that has to be calculated is the power dissipation on the resistor. As you know, resistors come n different rated power values, for example 1/4 watts (250 mWatt), 1/2 watt (500 mWatt), 1 Watt etc. This value indicates how much power can be dissipated on the resistor in the form of heat. We therefore need to know this value for our circuit in order to select a properly rated resistor. The formula to calculate the power is this:


P_RES = If² x R => P_RES = 0.02² x 140 => P_RES = 0.056 Watts => P_RES = 56 mWatts

Therefore, a typical 1/4 or even an 1/8 watts resistor is sufficient to dissipate the 56 mWatts of power.








2.Make your own LED Resistor Selector Dial.
 


Download file

LED Resistor Selector Dial

 

Download the PDF file from the above link	Print the PDF file. Make sure that you print it with the actual size	This A4 is what you want to print	Cut the paper in half. DO NOT cut the dashed line

Now you should have two pieces of paper. The left side with the two big wheels is the rotating wheel, the right side with the two smaller wheels is the fixed wheel. Let's make first the rotating wheel...



Making the rotating wheel

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Put a ruler across the dashed line	Bend the paper accros this dashed line	Now bend it back to back	If the disks are properly aligned, then the pin will go through the center marks!

You need to make sure that the two disks are properly aligned before you go on to with the next step. Make sure that the pin goes through the center marks of the two disks.

Apply glue to one side and glue the two disks together	Let the glue dry for a while, remove the pin and trim the dashed line away	Then apply glue to the rest area and glue the two disks together	This is what you want to make at the end

Let the glue cure for a while and then trim the paper around the disks	If the disks were properly aligned, then the disks are properly trimmed around its perimeter	Make a wider hole at the center ad you're done with the rotating disk

Let's make the fixed wheel

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Now let's make the fixed wheel.

First, trim the wheels. Notice that the wheels are NOT separated!	Then remove the windows from the wheels	Now bend the wheels across the dashed line. Use the pin to align them perfectly as before	Use a thicker nail to make the hole wider.

Putting everything together

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Get the 2 disks and place them side by side. Make sure that the wheels show the same face (resistor power or value).	Now put the rotating wheel between the fixed disk like a sandwich.

Now you wanna use Y-shaped nails to fix the dial selector together	Put one of these nails through the holes at the center	Push it all the way through	And then bend the two legs of the nail.

 How to use the LED Resistor Selector Dial

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You can hold the selector with one hand from the rectangular piece that extends on the left side of the fixed circle. With your other hand you can hold and rotate the rotating wheel:






The fixed wheel (the smaller one) has the LED voltage. The rotating wheel (the larger one) has the supply voltage. You wanna match now the supply voltage with the LED voltage by rotating the bigger wheel. For example, if the supply voltage is 5 volts and the LED voltage is 2.2 volts (typical for red LED), this is how you should align the wheels:





You are now ready to get the resistor value. From the "Resistor Value" window you can read the value for 3 different current rates: 10, 20 and 30mA:





As you can see, for 20mA current you should select a resistor around 140 Ohms...


Finally, flip to the other side to read the power that needs to be dissipated on the resistor:





The power is between 55 and 60 mWatts..

More LEDs in series???

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What if you want to use one resistor for 5 LEDs in series? How can you use this tool to calculate the resistor value? Simply, add all the forward voltages of the LEDs and use this value instead. If for example you want to connect 5 cool white LEDs in series and each LED has forward voltage 3.3 volts, then the total forward voltage will be:


Vf_total = 5 x 3.3 = 16.5 Volts


Now, if the supply voltage is for example 22 volts and you want to allow 30 mA of current ...

22 power supply aligned with the 16.5 volts required for the 5 LEDs in series	For 30mA, the proper resistor is 180 Ohms	170 mWatts is approximately the power that needs to be dissipated on the resistor

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1.LED driving and controlling methods

  there are many people who would like to know more about driving and controlling LED lights, and second because i was provided an excellent LED driver chip from Farnell for test, and i wanted to put it under the microscope. So i will place this chip against some other LED drivers to see how good it is.

The chip that I'm talking about is the A6210 from Allegro Microsystems. It is a Buck-Regulating LED Driver able to drive up to 3A load with constant current, with switching frequencies up to 2 MHz and supply voltage from 9 to 46 volts. It has an optional PWM input to control the brightness of the LED. The sense voltage is down to 0.18 volts for higher efficiency.

The previous description may sound Greek to you, but after reading this tutorial you will be able to design your own LED driver. Special thanks to Farnell and Element14 for offering three of these chips for test.


You can now start reading the theory pages:

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Page 1: Quick info about LEDs and LED voltage control with limiting resistor

The simplest method to drive an LED

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Page 2: Single Transistor Constant Current Driver

Driving more than one LEDs with constant current

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Page 3: Single Transistor Constant Current Driver with voltage regulation

Driving more than one LEDs with constant current regardless of the supply voltage

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Page 4: The Transistor - MOSFET Constant Current Driver

A more efficient system to drive LEDs with constant current regardless of the supply voltage

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Page 5 and 6: Injecting PWM pulses to control the brightness of the LEDs

After having explained the basic methods to drive LEDs with constant current, i explain how can someone modify these circuits to control their brightness