Friday, October 1, 2010

Smart Car Race India 2010

Freescale Semiconductors and Centre for Electronics Design and Technology, Indian Institute of Science organized the 'Smart Car Race India 2010' from 27th to 29th September, 2010. Over 60 teams of engineering students from across the length and breadth of the country participated in the event. The prelims were held on the first two days. Thirty teams made to the finals that was held on 29th September. The top three teams were awarded attractive cash prizes.

The main objective of this national level competition is to foster the problem solving aptitude within the undergraduate and gradute student community. The challenge posed at the students was "to design and develop controller to steer a car on an unkown track". This is  implemented on toy cars equipped with on-board electronics. 

Freescale has been organizing this event in China, Korea, Malaysia and Mexico. This is the first time the event was held in India. From now on, this shall be a regular event in India too.

Related LInks:
Edit on 17 Dec 2010: Video added

Wednesday, September 15, 2010

The Art of Teaching

Much of our competence, and for that matter even the interest we have, in a subject is down to how well we were taught that subject. A good teacher has a profound influence on the capabilities and performance of his pupils in life. Science and engineering education is no exception. With my sights set on taking up teaching and research as a career, I'm always impressed when I come across someone who is exceptional and creative in his pedagogical methods. 

Recently, thanks to YouTube, I stumbled upon a few lectures from one such gifted teacher, Professor Walter Lewin, who teaches Physics at MIT. His methods are truly worth emulating as the following video would testify.

With several universities across the world opening up their lecture halls to the world, by providing free access to recorded lectures, the enthusiastic student of today has an invaluable resource to tap from.

Here are a few such links from generous universities:

Tuesday, June 1, 2010

Lightning - An Overview

[Download pdf file of this article here]

Lightning has always evoked fascination. Recently I spent some time contemplating and perusing through lots of resources on the internet and in print about lightning and the possibility of harnessing energy from it. Here's a brief overview of what I gleaned from various sources.

The important figures associated with lightning (typical values):
  1. Voltage between cloud and ground ≈ 10^8 to 10^9 V (upto a billion volts)
  2. Current during lightning discharge ≈ 10 to 200 kA (hundreds of kilo-amperes)
  3. Peak power involved ≈ 10^10 to 10^12 W (several giga-watts)
  4. Energy discharged ≈ 250 kWh (hundreds of units)
  5. Temperature ≈ 30,000 ºC (about five times the surface temperature of the sun!)
  6. Duration of discharge ≈ 0.2 s
A collection of interesting facts about lighting:
  1. On an average, the earth receives 3 million lighting flashes a day i.e. about 40 flashes every second.
  2. Tropical Africa is the most struck by lightning, with up to 295 days a year subject to electrical storms. Lightning strikes most frequently in the Democratic Republic of the Congo (formerly Zaire)
  3. 90% of all lightning strikes are cloud-to-cloud.
  4. Thunder produced by a lightning strike travels one mile (1.6 km) every five seconds. Thus, counting the number of seconds between the visible "flash" and the audible "bang" and dividing by 5, provides the distance in miles at which the strike has occurred.
Types of lighting: 
    1. Cloud-to-ground
        - Negative lightning
        - Positive lightning (bolt from the blue!)
    2. Cloud-to-cloud or inter-cloud
    3. Intra-cloud
    4. Cloud-to-air

How it happens:

Certain types of clouds - known as cumulonimbus clouds or thunderclouds - develop a strong charge separation with large negative charges at the bottom and large positive charges at the top possibly due to the friction (tribo-electric effect) between upward rising air and falling water droplets and ice.  A large “shadow” region of positive charge is created under the cloud due to electrostatic induction. When the electric field between the bottom of the cloud and the surface of the earth becomes strong enough, streaks of ionized air (negatively charged stepped leaders) reach out downwards from the clouds while positive streamers grow upwards from objects on the earth. When the two meet, a short circuit is created for humongous amounts of charge to be transferred from the cloud to the earth within a fraction of a second and that is what we see as lightning. The huge current through the conducting channel creates large amount of heat, light,  sound and radio waves.

Keywords: cumulonimbus clouds, thunderclouds, triboelectric effect, electrostatic induction, negative stepped leaders, positive streamers, return stroke, dart leaders, secondary strokes

Lightning Effects:
  • Lightning contributes to nitrogen fixation.
  • If the lighting current path passes through rock, soil or metal these materials can become permanently magnetized due the fleeting but very strong magnetic field induced by the large current. This effect is called Lightning Induced Remanent Magnetism (LIRM).
  • The heat of lightning which strikes loose soil or sandy regions of the ground may fuse the soil or sand into glass channels called fulgurites.
  • Trees are common lighting targets. Of all common trees, the most frequently struck is the oak.
  • The electrical discharge during lightning rapidly superheats the discharge channel causing the air to expand rapidly and produce shock waves heard as thunder. The rolling and gradually dissipating rumble of thunder is caused by the time delay of sound coming from different portions of a long stroke.
Lighting Safety:
  • Lighting can even reach you indoors of you are in contact with the telephone (landline) or plumbing – basically anything that has a continuous conducting path extending to a place outdoors where the lighting can strike.
  • Water is an excellent conductor, so it’s wise to stay away from lakes, ponds and pools during a lightning storm.
  • Even if the bolt strikes an object near you, the ground current that flows from the point of strike in all directions can easily flow through a person standing with his feet part. So during a thunder storm it’s advisable to (1) stay low, in a crouched position (to reduce the probability of the bolt striking you) especially if you are in a flat region with no taller structures than yourself  (2) Keep your feet together and have as little of your body touching the ground as possible (to reduce the ground current flowing through you)
  • Rubber tires aren’t why you are safe in a car during a lightning storm. In strong electric fields, rubber tires actually become more conductive than insulating. You are safe in a car because the lightning will travel around the surface of the vehicle and then go to ground. This occurs because the vehicle acts like a Faraday cage.
  • Lighting arrestors and lightning rods
  • Static discharge wicks in airplanes
Problems with harnessing energy from lightning:
  1. The discharge of extremely large power concentrated within a very small span of time would require a very very huge and costly device to tap the energy.
  2. Even if the device is somehow built, lightning itself is highly infrequent, inconsistent and unpredictable. We never know the exact time and place where it will strike.
  3. Even if you manage to find a place that receives lighting consistently, a lighting strike dissipates so much energy in heat, light, sound and radio waves that there is not enough left to be worth collecting.
Possible ways to overcome these problems:
  • Do not let the lighting discharge happen as a sudden flash. Find a way to slowly drain the stored charge in the cloud-to-ground capacitance and store it somewhere for being tapped later on.
  • As most of the lightning strikes are cloud-to-cloud and also because much of the energy in cloud-to-ground discharges are dissipated in the intervening medium as heat, light, sound and radio waves, the only way to harness energy from lightning is to go to the clouds and do something up there. To put it in Dr. Martin A. Uman’s words, “trying to harvest the energy of lightning from the ground is hopeless”.
References and useful links for information on lighting:
  1. Lightning Primer from NASA
  2. NASA answers on lightning energy harvesting
  3. Wikipedia article on lighting
  4. Good lighting explanation and videos
  5. Can lightning be tamed?
  6. Harnessing lightning power
  7. Harnessing lightning power
  8. Harnessing lightning power
  9. Discussion forum
  10. Lightning Farms
  11. A detailed article on lightning
  12. Nikola Tesla: Power from Lightning
  13. Lightning”- A book by Dr. Martin A. Uman, a leading authority on lightning.

Sunday, April 25, 2010

Sleep Detector Power Saver

I remember umpteen instances when I've seen people leave their lights and/or televisions turned on and fall asleep. While the person is recharging himself his appliances are continuously hogging power all night for no useful purpose at all. Of course the easiest solution to the problem is for people to realize the mistake and be responsible enough to turn off all unwanted utilities when they go to sleep.

But since we still have so many careless people around, there is a potentially huge market for a product that could detect sleep in a person and take action accordingly - switch off lights, TV etc. Sleep detection could be done based on monitoring of one or more of various parameters - heart rate or pulse rate, body movement, body temperature, respiration rate etc. The major challenge in such a product would probably be to identify which among these myriad options would provide the cheapest and the most reliable way to detect sleep. Any answers?

[This post is an elaboration of Problem-3 on the post "Nine Problems Worth Solving"]

Monday, April 19, 2010

Jerky Ride Writing Assistant

Travelling by bus, train or car can be tedious if the journey is long and more so if you are all alone. Many resort to reading in order to pass time. There are times when I felt like writing something when traveling. But because of the jerky nature of the ride, it becomes rather difficult to write anything legibly. It's at times like these that I've often wondered if there could be some device that could be strapped on to my wrist, which would allow me to write normally the way I would in a stationary and jerk-free scenario. It could probably compensate for the jerks by applying precise forces (of the right magnitude and direction) on the hand - some sort of an active noise cancellation!

Another possible solution to the problem is to have some sort of a damper or a shock-absorber structure that keeps my hand and the notebook steady irrespective of vibrations in the vehicle. Any thoughts and/or suggestions from the reader are most welcome.

[This post is an elaboration of Problem-2 on the post "Nine Problems Worth Solving"]

Wednesday, January 27, 2010

Microsolar Cell Technology

[Image Courtesy:]

A new and exciting
solar cell technology developed at the Sandia National Laboratories (USA) promises a bright future for solar power. Check out the news release on the following link.

Glitter-sized solar photovoltaics produce competitive results
Adventures in microsolar supported by microelectronics and MEMS techniques


  • A new solar cell technology developed at Sandia National Laboratories (USA)
  • The cells are fabricated using microelectronic and microelectromechanical systems (MEMS) techniques common to today’s electronic foundries.
  • They use 100 times less silicon to generate the same amount of electricity as conventional crystalline silicon solar cells.
  • 14-20 micrometers thick, they are 10 times thinner than conventional 6" by 6" brick-sized cells, yet perform at about the same efficiency.

Tuesday, January 19, 2010

Solar Energy Storage

Today, I had the opportunity to be at the Faculty Hall where Professor Charles M. Vest, President of the US National Academy of Engineering, and President Emeritus of the hallowed Massachusetts Institute of Technology was delivering a talk titled "Engineering Education in 21st Century". Of the several germane issues touched upon during the lecture, Prof. Vest's mention of fourteen grand engineering challenges was of particular interest to me. One can take a look at the list here.

Being one with a soft corner for renewable energy, I found the first one - Make solar energy economical - to be of utmost importance. Addressing the problem of storing solar energy for times when the sun isn't in sight (nights and cloudy days), the article puts forth a very interesting idea based on mother nature's ways.

Another possible solution to the storage problem would mimic the biological capture of sunshine by photosynthesis in plants, which stores the sun’s energy in the chemical bonds of molecules that can be used as food. The plant’s way of using sunlight to produce food could be duplicated by people to produce fuel. For example, sunlight could power the electrolysis of water, generating hydrogen as a fuel. Hydrogen could then power fuel cells, electricity-generating devices that produce virtually no polluting byproducts, as the hydrogen combines with oxygen to produce water again. But splitting water efficiently will require advances in chemical reaction efficiencies, perhaps through engineering new catalysts. Nature’s catalysts, enzymes, can produce hydrogen from water with a much higher efficiency than current industrial catalysts. Developing catalysts that can match those found in living cells would dramatically enhance the attractiveness of a solar production-fuel cell storage system for a solar energy economy.

So here's a challenge for all chemical scientists and/or engineers to tackle. Anybody listening?

Wednesday, January 13, 2010

List of Emerging Technologies

Wikipedia has put together a handy and impressive list of emerging technologies with their current status, potential applications etc. It's a must read for every engineer worth his salt. The technology areas covered are energy technologies, transportation, information technology, biotechnology & bioinformatics, robotics & applied mechanics, material science and others.

Here's the link: