My parabolic-mirror-solar-grill - Story and Design

This weekend, I designed my own solar grill at home using some of the unused articles and also some things were bought at nearby home appliance shop or novelty store.


Background for coming up with this crazy idea was that my android smart phone Motorola Defy was draining out of battery in less than one day with all radios enabled in it esp like mobile data, wifi, GPS. I needed a USB travel charger badly and bought a solar powered + usb powered (4400 mWh) which could charge universal devices like Camera/Ipod/Phone etc., on the go. Its output rating is 5.5V,500mA. It works just good in critical power needs during my trekking/camping. I had underestimated the solar power till then until it helped me really when I needed the most.

A few months back I had been to Lakshadweep islands where the sole energy for the whole island was Solar power. I was really amazed at the self sustained way to renew energy resource even for desalination of water using the temperature difference between the cold water of deep sea and the hotter surface water. Even the entire lighting was done by an array of solar cells.

I was looking at the ways to harness the this power in very small scale and came up with website called GREENPOWERSCIENCE which does build the acrylic parabolic mirrors and extreme powerful fresnel lens which was well suited for my purpose but was not within the reach of my budget anyway. Then I went in search of ways to build my own parabolic mirror. Dan of the GreenPowerScience explains a lot of ways to make a user defined one with casting mortar and using it to prepare a cement mold. Grease the mold, then use 3 layers of fiber glass wool and polyester resin to bind them into a parabolic polyester dish. Well, this preparation was too tedious (but really economical on some scale if we plan to roll out many) but I wanted a better and faster way. The best suited idea for me was given by another youtube video which used the TV antennae that comes with the dish which is of parabolic shape to converge the KU band of TV signals into a focal point for better reception. So I bought a scrap dish from reliance big TV workshop near my place for 350 INR (Found a good quality dish in a stock pile of Defective LNB dishes) Its a 60 cm diameter dish which I bought with the clamps and bolts for fitting.

[If you are not into mathematics of conic section called parabola and want to understand why it works to choose this shape, please refer to parabolic reflector and see here to understand the theory and check out the illustration]

Next step was to prepare a reflecting surface for the entire surface of the parabola. This was done by low cost Aluminum foil of food grade quality. This costs about 40 INR for about 7 mtrs X 30 cms. Not even 1/4th of it was used to cover the dish surface. I cut it into strips of regular sized rectangles (better to make trapezoids for easier coverity with very less wastage) to paste it with a child safe glue. The glue must be water based and it should be non-toxic as it might get heated and may fume in direct sunlight. Even with the application of tin foil all over the surface, the reflectivity is pretty bad about just 35-40% with the wrinkles and overlapping edges. The full sheet as such if stuck on flat surface would give about 55% of reflection. Also I read about Mylar, Foylon and other reflective vinyl sheets which could be used for this but again cost issues exceeded my low budget project. I plan to upgrade to better reflective surface tearing down the current tin foil surface as it is not durable for long and the temperature tin foil reflection generates is very less and is insufficient to boil water. Using a mirror (glass based) would be optimal for me as it will be lesser initial cost but would require a lot of work to cut mirror into several hundreds of pieces to cover entire area of the dish.

I read somewhere that a square meter of earth's surface lit by bright sunlight generates can be equivalent to 1000 watts of power. So a 60 cm dish with good reflective surface will give above 560 watts of energy.
If you have concentrated a beam of light by magnifier lens to burn paper during your school days/for your curiosity then you can imagine the power of the parabolic concentrator.

After the reflective parabolic surface then the problem comes with the proper mount. Mount can be made anything and problem here is to get a grill at the focal point of the sunlight after the dish is mounted on any surface. It can be anything from an unused table fan bottom, a tripod etc. My initial attempt to use a 4 foot long flower vase stand went in vain as it could not withstand the entire weight as its center of gravity went outside the dish when mounted :P

After hunting more and more for unused items at home, I found a cradle (!) in which I used to sleep when I was a baby ;) An antique piece in rust but still standing :P Good thing is that its easily dis-mountable with 4 rivets at the bottom. I shall work on a good paint job sometime next week on it to make it a more durable.
It has got two hooks on the sides which helped me to put up the stainless steel round grill with a wooden handle on top of it with the help of small sized bungee ropes which holds it in place. Good thing about these ropes is that they got good tension retaining ability, they are insulators, and most important of all that I could vary the position and angle of dish for sunlight based on placement of hooks on the side rods of cradle.


Sad that there wasn't much sunlight today as it was rainy and gloomy all day long. So I couldn't test for temperatures it could go with direct sunlight. I shall update it soon after my next series of tests. :)


Things I bought for grill:
Parabolic dish - 350 INR
Aluminum foil + Glue - max 40 INR
Bungee ropes - max 30 INR each (I had some of them already for traveling on bike)
Steel grill - 140 INR

(You may also require a plastic ruler, blade to cut the foil)

Well within 600 INR of cost it is doable and it took me just 2 days with each day spending about 5-6 hours of work all alone on building this. I started building it on Saturday morning and completed on Sunday evening :)

Below are some pics that i took in building my solar grill. Will update more on the mirror upgrade that I plan to do and probably post a video soon of me cooking some good stuff ;)

Check out some FAQs listed here if you have something in mind to start a project something like this.

Cheers!
Karthik

I give thee my troth

"... I give thee my troth"

You were that special unknown stranger

for years, I have been waiting for.

Bumped into each other at some crossroad of our journey,

Never having a thought that we would travel together so far.

At first, I thought I was just enchanted by your charm.

Sooner I realized that I had lost myself in the innocent beauty of your heart.

As we kept walking in the shade of companionship,

Our feelings started to resemble a lot.

When you asked for my hand in yours

I was more than happy but at the same time was quite worried

For I had to grow beyond the usual dad's little girl

-and take part in my own life's play, a character in lead.

Here I come, betrothed to you for a vow -

that you take good care of me as good as my dad

Ready for the seven steps around the holy fire and tie the knots of commitment for life,

With the only hope of all the woven dreams that we together had.

(Written - August 13th 2011)

[Dedicated to my Mom and Sister-in-law]

Ranga Shankara - Sattavara neraLU

Last Sunday, I happened to browse through the newspaper and found that there was a Kannada play called "Sattavara neraLu" (Shadow of the dead) Playwright : G B Joshi. Director: B.V Karanth.
Having heard that it is a good drama, I went to watch it at Ranga Shankara theater.
Indeed it was a different experience as it was my first time. I had never been to a live theater show before. I thoroughly enjoyed the brilliant theater experiments, effects with lighting and shadows, stage design. The timely lyrics of Purandara dasa literature like "illiralaare allige hoogalaare","kurudu naayi santhege banthanthe","aachaaravilladha naalige","aadhadhella oLithe aayithu","Donku baaladha naayakare","Lolalotte" to suit the mood of play enlivens Sattavara neraLu's theme.
Long live Shankar Nag's dream and a bow to the all the artists/directors/playwrights.


Below is the theme of the play - (Courtesy citizenmatters.in)

Subtly pulling a philosophical string and delineating a dreadful tune, Sattavara Neralu shakes the stable philosophical base and intellectually inquires into the eternally rooted and firm beliefs in our society.
Narayana is forcibly pulled into Sanyasa and made seer of a Mutt. A ventri vogue of king maker Krishnacharya, Diwan of the Mutt, seer is ashamed of his pretentious celibacy unable to suppress his un-satiated worldly desires and suffering the onslaught of intellectuals thronging at Mutt seeking philosophical and spiritual clarity subjected to scrutiny and judgement.
Diwan manages to send seer on a pilgrimage and receives news that seer moved heavenward. Diwan immediately builds a Vrindavan in the name of the deceased seer and carries on Mutt activities many years. But seer turned Narayana, actually alive, returns to confront Diwan, Diwan manages to maintain that dead seer is in Vrindavan. Frustrated seer reversed to mortal Narayana threatens to reveal the truth, but incorrigible Diwan challenges that devotees would blindly believe what they practice for ages in deference to and total disbelief of what is blabbered by Narayana because mortal Narayana is now bereft of the seer in him.

Fortress of solitude

A lot of people around me get freaked out by my silence. I guess, They often think what is wrong with this "lone lonely loner"! Some around me ask me to be more expressive. I get tired of people asking me - "Why are you so much quiet?" whenever I try to mix with people in a group. But very close friends of mine tell me not to change and be just the way you are!

I am happy not being a very social animal. Even being put in a big social group at family wedding/some party I feel a lot deserted! I will have very short replies for people's (irritating) questions and do enjoy killing time in analyzing everyone's reaction and body language. Social contact seems like burden to me most of the times. Majority of the society is too loud and outgoing.

I am totally bad in front of a crowd. I have my own fears to talk to a bunch of people. It would be much easier to give a technical talk than general talk as analytical part of your brain filters out any impractical words come out of your mouth! Sometimes I go blank in talking what is expected out of me, sometimes I even stammer with all the nervousness. It all depends on the exposure of the world around that I got when I was young. Well, I face my fears till today every time I am being laughed at and made fun. I fight my own fears only by facing them regularly.

Being an introvert loner is not so bad at all. It's cool when I don't attract much attention. I feel that I'm on my own and I'm free. I don't have to care about what people will think about me. I don't have to be the "life" of the party to enjoy all the action going around. I have a lot of time to spend for myself and most importantly it helps me to work independently as a individual contributor even though I work in a team. I don't make enemies with anyone. I am good at burying a lot of secrets within myself. I get to go for solo bullet rides exploring around which helps me to get along with nature more closely. When people get my trust they have a real friend in making.

The bad thing about being a loner is that when you are tested with a lot of emotional turbulence you tend to easily lose yourself! One has to be strong not to let it overcome and become a phobia or a disorder of any kind.

I dedicate this random thought to millions of people around who live(or agree to) in their fortress of solitude. :)

Temet nosce

After a long time I get to blog something. Thanks to the power maintenance for couple of days being done at office.

"Temet nosce" - A Latin phrase meaning "Know thyself". I chose this title based on the aphorism written on the plaque above the Oracle's kitchen door in the movie "Matrix", one of my favorites. The post itself briefs you about why the use of this strange title at the end.

Being a teetotaler in a farewell liquor party of an ex-colleague/new year booze party with present ones, you get to experience a lot of offline faces of your colleagues and bosses, some good- some bad - some even ugly! The best part is that you alone remember everything after coming back. ;)

I always wonder why people are so desperate to get so intoxicated with the drug called alcohol? Some strange answers that I got were like: they get drunk to be happy as they feel at liberty to talk anything mean! Some get simply drunk for the thrill-seeking. Some people drink in opinion that someone thinks big of you! While some others think its social to be drinking at party like these and while others drink because of peer pressure.

Many asked me to give up my beliefs and tried very hard to make me succumb to the so called luxury. I was looking at everyone's face to see if someone out there really felt what it means to be yourself and I was so happy to see that at least someone believed in me in giving a nod of disapproval not to give in.

I really liked the compliment that was given to me sometime during the conversation - "A silent warrior". So true that we all are trying hard to fight the battle within.

He always awaits in your subconscious
poised to greet the luxury when you give in,
while I stay wide awake engaged in
the endless covert fighting with my own evil twin.

He laughs at me with exultant joy;
Jeering at all my weaknesses.
While I stay tranquil amidst the uproar
Letting him not know about my failures.


Neither of them take a break ever
indulged in a series of confrontations within
Putting the blame on each other
Tending to unite yang with its yin.

With all the constantly running inner dialogue between my evil twin and my own conscious mind, I still somehow feel that I am a stranger to myself! Do we really "know ourselves"!?

Live.Love.Rewind

I am directly picking this title off the Sony Handycam's Ad. Today, we (our family) had been out on Deepavali shopping spree. Bro and SIL bought a new Sony Handycam to gift ourselves on the occasion and to treasure moments with yet-to-be-born my nephew/niece :) Never to miss the moment of all his/her first's in life... be it first touch, first smile, first words spoken, first step, first masterpiece, first rock show, first make up and most important of all those first words calling me "mama" ;) and so on... :)

At the Sony world/center, There was showcase of a lot of electronics. Above the display of Handycams, there was an large LCD TV which was looping through this advertisement below.
http://www.youtube.com/watch?v=LBohbQB-55o

It is all about a father reliving the moments of his daughter from childhood to her marriage. A lovely cute ad indeed! This took me back to an incident of which I was a witness a couple of weeks back. I had been to Malleshwaram,Bangalore to pick up my mom from her evening class of psychology. I was waiting outside in car for the class to get over and was just watching strangers around to see their actions, reactions, instincts and do a micro level sociology study of people and myself. That's my favorite pass-time! :D
As I tuned in some soft FM music in car stereo, I noticed an auto-rickshaw stopping next to car on the other side of the road under a street light. A pretty girl in her mid 20's stepped out with a lot of luggage to find her residence. I couldn't help watching her. I was a little safe as I had hid behind the tinted glasses ;). No sooner her father came to place and talked to her giving her a good tight hug and helped her with her luggage home. There was so much joy in his face on seeing his little kid come back home after a long time and all the expressions on his face told how badly he had missed her - Life is just fleeting moments of joy worth waiting for and the uncertainty is what makes life more beautiful. :)

Cheers! and Happy Deepavali.

Lineage, Lifestyle and Learnings

We as students read history right from our school days to get to know of all the irrelevant facts about who did what, when and where and how! I am not a historian but I believe in saying that "history repeats" because anything and everything I am currently experiencing in this world has been experienced by a lots of others somewhere in the time-line. We study to learn from past mistakes, gather data for prediction of life events, know about cultures but the history itself looks and probably is so much biased if we go only by the available writings.

Coming to a very small scale of geological time frame, If you ask me a simple question of what my great grandfather did for a living and his story of life. I have no clue! We do not know much more than our grandparents in our lineage. As a parent, does one really give knowledge of how social and financial life earlier was to his/her child? We are afraid that the youngster might develop some kind of impression over the family, relatives and hide some of the facts as we bury them deep down within ourselves. We are afraid to expose our problems in front of our children and make them understand the reality of life.

Today, we live in the era of technology, booming shopping malls, hyper-markets and multi-national business enterprises. The lifestyle of people, a generation earlier, were lot different from what we are going through now. Even the morals and values are not remaining the same. The attitude and pace over which we are leading life is changing very fast.
A simple instance: Nowadays, If a grandfather tells his grandson that he didn't have something called TV at his time to watch the kid shouts back to him saying that you are cooking-this-story-up for making me not watch the TV! Having the company of upper class society friends in junior school, the kid even comes and asks the parent if we are poor in just owning a Maruti Alto while his friends travel around in Honda city.

I have several open questions on my mind on my above bizarre random thoughts:
Why is society failing to learn from past and teach next generation? Is it the high rate of inflation over decades? Ever increase in economical gap between upper and middle class? Is it that we have lost the habit of reading Indian novels which expose rural side of our country to relate to our ancestor's life? Is it that we are losing something in over protecting our kids so that he never sees what actual suffering is? Are we shedding moral values down the drain in our pace of earning money and make a grand living?