Wind Energy

My daughter got a co-curricular school activity in early September about renewable energy models. The students were tasked with making a model depicting one of the three renewables: solar energy or wind energy or hydroelectric energy. A link to a sample video was provided for some inspiration too. Included was also a reminder note: The model can be non-working. (Emphasis was the school’s.)

We chose wind energy and decided to make a non-working model with a couple of windmills, a house and farming land around it. As she and her mother started working on making the actual model, I started wondering, “Can a working model be made?”. I mean it seemed like just sticking a pinwheel fan on a dynamo generator should do the trick of lighting up a single measly LED! How hard could it be, right? As it turns out, it is actually quite a pain to make a working model of a windmill out of just those 3 things! I list here all of my failed attempts to make a working “windmill” with the help of a ceiling fan providing the required wind.

Attempt 0: Her mother likes my “grand” idea for the “project” and agrees to source the electronics components. She gets 10 green LEDs, wires and two motors used in toy cars (cuboid shaped with a red plastic end). As it turns out, this motor can be used as a generator (the same working principle in reverse) but I did not know this fact at that time so I ask her to source a generator specifically. She gets two dynamo generators similar to those used in bicycles (I guess), one of which we use till the end of this “project”. (As it turns out, the red one could not have worked for our purposes anyway!)

Attempt 1: We make a couple of pinwheels (we discard the idea of a 3 blade proper-looking windmill quite early on because we can not make it aerodynamic enough!) and source a plastic stub from Sakura’s toy collection (a kids’ science kit for electrical stuff) to fix the pinwheel to the generator’s axle. We switch on the ceiling fan, turn it to max and let the pinwheel rotate away. The LED does not turn on. No surprise there!

Attempt 2: I search about what can be done and settle on Gemini’s suggestion to spruce up the pinwheel to make it more sturdier and rotate faster and even use gears to rotate the axle of the generator even faster so that enough voltage is generated to light up the white LED.

As it turns out, these LEDs need ~3V to turn on and no way was the pinwheel’s rpm enough to generate any voltage close to that. I buy a toy gear set and make a cardboard enclosure for the gear mechanism but at the end of the day the pinwheel does not rotate the geared generator at all. This is because (it is obvious now) more power is required to turn a 5:1 gear set than just the generator’s axle directly. So this is a complete failure.

Attempt 3: I am back to the pinwheel directly attached to the generator’s axle. I finally “painstakingly” use a battery tester to measure the voltage being generated by the generator and it is a disappointing ~0.6V! The 5:1 gear box idea was quite good as it would have really given ~3V to light up the LED if the pinwheel had rotated as required. Another idea strikes: let me replace this bulky generator with a sleek drone motor (which can also be used as a generator). Another day, another order for the drone motors and while I am at it, let’s buy a proper multimeter too.

With 4 drone motors in hand, I make a smaller pinwheel for this smaller generator and no prizes for guessing, this also does not work because the voltage generated now is measly ~0.06V… 10× lower! Arrgh! But then it is post-priori obvious that this would not have worked because these drone motors are rated for very high rpm (~50K) for ~3.5V and the bulky generator is rated for just ~5K worth rpm for ~12V so from pinwheel’s low (100-500) rpm, no wonder the voltage drops so drastically. (The “red motor” mentioned above would not have worked either exactly for this reason.) This is utter disaster.

Attempt 4: Back to the pinwheel directly attached to the bulkier generator which is happily generating ~0.6V at max ceiling fan speed. Gemini finds technical specifications of this generator and “calculates” from the generator’s 0.6V that the pinwheel must be performing ~150 rpm, which is nice to know but utterly unhelpful for my purposes! Because the rpm of the pinwheel cannot be increased any further so I need to boost 0.6V to 3V. I ask Gemini for simple DC voltage step up circuits. It talks about “Joule thief” circuit and suggests a ready-made circuit to buy. This circuit requires minimum input voltage of 2V so I call it quits on sourcing another product that might not work! Also there is no way of making a Joule thief circuit on my own as I am not salvaging a ferrite core and transistor from anything in my surroundings in a million years.

Joule Thief Circuit Video Tutorial

Attempt 5: After having a few sleepless nights with ever-increasing urge to get this “windmill” light up a single LED, I decide to follow the maxim: Go Big or Go Broke! I order ₹4K worth of electronic components (including the Arduino Uno board kit for later use by Sakura, hopefully!). With the above tutorial video running in loop in front of me and having ransacked Sakura’s toy closet to get my hands on two ring magnets (instead of the ferrite core), I cobble up this JT circuit and with a “dead” AAA cell, it lights up the red LED (to “match” with the red ring magnets)! WOW! So this circuit is definitely boosting 1V to 3V.

Now is the moment of truth. The moment way past the actual co-curricular day where Sakura had to present her non-working model. The moment when I replace the cell by the “windmill”: WHhhaaattt!!! WHhhyyyy??? The LED does not light up. So apparently, this circuit is not able to boost 0.6V to 3V or was it just luck that the magnet “worked” with the AAA cell. Anyway, we now know what needs to be done.

Attempt 6: I order the final missing component: the ferrite core. What’s ₹400 more having spent ₹4K already? They arrive in a pack of 5 after what seems like ages. I pick out one, wrap wires around it (in a slightly different way) and remake the JT circuit. It works with the dead AAA cell. Good! Now again is the moment of truth. Nothing else matters because this is the brink of all that has transpired for the last few weeks. This is the moment when I replace the dead cell with the live “windmill”…

Our faces light up along with the red LED!

The final setup is shown below with a green LED to match the colour scheme of the ferrite core and the overall theme of green energy.

Finally, we should take stock of what all we did and what all we spent to achieve that. We did make a Joule thief circuit (barely worth ₹200) to boost low voltage output of a generator (~0.6V) powered by a “windmill” to a level that can turn on a standard (green, red, white) LED requiring ~3V. As for what we actually spent to get there, here is the itemized breakdown:

• Motors, LEDs, wires – ~₹400
• Toy gear set (unused) – ~₹350
• Multimeter – ~₹1400
• Electronics components – ~₹4000
• Ferrite cores – ~₹400
• Project time – ~1 Month
• Sakura’s lit up face when windmill worked – Priceless

Here’s the proper finale for those who have reached till the end.

Windmill with Joule Thief Circuit

Next order

356th Post…

As this year rolls on and this post gets published, I have written a year worth of posts on this blog! In less than 20 years! That is quite an achievement! Worthy of a grand celebration, indeed!

And that is why I will share here the following poem by Dr. Prabha Thakur on Life – ज़िंदगी – Zindagi (about which this blog is, if you’d forgotten!), celebrating all its aspects – from the negative to the positive, from the mundane to the extraordinary, from the first to the last, and the most important, the uniqueness of it all! Please enjoy this poem and have a cake on my behalf!🍰

ज़िंदगी

ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही
पर ज़िंदगी भाती तो है, ये सब का दिल लुभाती तो है
ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही ॥

आबादियाँ वीरानियाँ, खुशहालियाँ रुसवाइयाँ
सब ज़िंदगी के नाम हैं, ये ज़िंदगी के ईनाम हैं
खट्टी सही मीठी सही, ये ज़िंदगी कड़वी सही
है ज़िंदगी तो हर बात है, तो सब ज़िंदगी की सौगात है
ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही ॥

सूरज गगन धरती हवा, सुख-दुख हंसी सरगम पिया
इसने हमें क्या-क्या दिया, इस ज़िंदगी का शुक्रिया
ये दो घड़ी का सपना सही, ये चार दिन का नगमा सही
पर ज़िंदगी गाती तो है, ग़म में भी ये मुसकुराती तो है
ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही ॥

हारो न तुम बढ़ते रहो, इस ज़िंदगी से लड़ते रहो
खो जाए गर तो फिर ढूंढ लो, टूटे अगर तो फिर से गढ़ो
ये मूर्ति कच्ची नहीं, इससे जफ़ा अच्छी नहीं
ये जीत है ये प्रीत है, गाओ अगर तो ये गीत है
ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही ॥

थोड़ा बुरा थोड़ा भला, तक़दीर का है सिलसिला
जो भी दिया वो ही मिला, फिर ज़िंदगी से कैसा गीला
अमृत यही मदिरा यही, विष मान लो तो विष ही सही
ये जाम तो पीना ही है, तो हँस के जियो तो जीना भी है
ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही ॥

क्यों मौत की माँगे दुआ, जाना तो है फिर फ़िक्र क्या
कुछ ज़िंदगी में करके चलो, ये क़र्ज़ है भर के चलो
सच्ची सही झूठी सही, गर ये नहीं तो कुछ भी नहीं
इस दास्तान को उनवान दो, इस ज़िंदगी को पहचान दो
ये ज़िंदगी ग़म ही सही, ये ज़िंदगी कम ही सही ॥

– प्रभा ठाकुर

Of course, there is a live recitation of this poem by her and it follows.

'Zindagi' by Dr. Prabha Thakur

End of an Era in Urdu Shayari

About a week after the death of MATLAB’s Cleve Moler, another death rattled me and the world became that much more sadder. It was the death of the legendary poet Bashir Badr. He was a towering figure in the world of Urdu Shayari and mushaira (recitals), both literally and figuratively. His usage of (mostly) simple language, mastery of words & expressions was so exceptional that his recitals went deep within one’s self and raised emotions that one did not know one had!

Since he realized the seriousness of the onset of dementia in his later years, he voluntarily stopped attending poetry recitals. As his condition worsened, he even forgot his mushaira days. It was a saddening end of sorts but he will always be remembered for his showmanship and unique Shayari as he desired. Many obituaries and eulogies have appeared online since then. Let me share one from BBC Hindi.

One anecdote about his graduate days (that I had heard during my graduate days) has stayed with me even today because it seemed apocryphal but I wanted it to be so true. The article above more or less confirms it, so let me re-iterate it again here: During his M.A. studies, some of his Ghazals were part of the college syllabus (something he was proud of). During one viva exam, one examiner did not agree with his interpretation of a Sher; that Sher which was his own! 🤣

After the sad news of his demise, I decided to buy one more of his books (I already have one) and I got this one:

Let me share some Shers from this book (whose title means “Hope”) as an homage to this great personality and pure soul. First a Sher about Gods: [Do pardon my sketchy translations or read the relevant tab above.]

सब लोग अपने अपने खु़दाओं को लाये थे
इक हम ही ऐसे थे के हमारा खु़दा न था

Sab log apne apne Khudaaon ko laaye the
Ik ham hi aise the ke hamaara Khuda na tha

Everyone brought the Gods of their own
I was the only one with no God of my own

Next a few Shers from a Ghazal about passage & stillness of time, likes & dislikes, happiness & sadness:

उस का भी कुछ हक़ है आख़िर
उस ने मुझ से नफ़रत की है

Us ka bhi kuch haq hai aaKhir
Us ne mujh se naFarat ki hai

They also have some right after all
They do have pure hatred for me

जैसे सदियाँ बीत चुकी हों
फिर भी आधी रात अभी है

Jaise sadiyaan beet chuki hon
Phir bhi aadhi raat abhi hai

It’s like eons have passed
Still the mid-night is here

हम दोनों की खू़ब निभेगी
मैं भी दुखी हूँ वो भी दुखी है

Ham donon ki Khoob nibhegi
Main bhi dukhi hun wo bhi dukhi hai

Both of us will get along very well
I am also sad and you are sad too

अब ग़म से क्या नाता तोड़ें
ज़ालिम बचपन का साथी है

Ab Gham se kya naata toDein
Zaalim bachpan ka saathi hai

How do I break my ties with grief
That cruel one is a childhood friend

– बशीर बद्र (Bashir Badr)

Before my tears start streaming down and short-circuit my computer, let me leave you with a

45 minutes recital by Bashir Badr

Supergravity @ 50

This post should have appeared a month or so ago. But the last month was a bit hectic: first with a trip to Stony Brook, second with jetlag upon return to Bengaluru and then with seasonal allergy infliction shutting down my brain for a good 4 days.

I will focus mostly on the first bit of information mentioned above. I visited Stony Brook last month from 1-7 June to attend the conference celebrating 50 years of the discovery of Supergravity by the well-known triumvirate: Sergio Ferrara, Daniel Z. Freedman, and Peter van Nieuwenhuizen.

This was a third conference of this type at Stony Brook with the first one held in 1979 (@ 3 years) and second one in 2001 (@ 25 years). I was glad to be a part of this historic event and being at my alma mater after nearly a decade. Though, it was sad that neither Ferrara nor Freedman could attend this conference due to health issues.

The three days of the conference were jam-packed with 7 talks each. You can find them on the conference page (linked via the poster above) along with the dinner speeches (worth a listen too, even for non-physicists!). Some of the talks were review/overview talks, some were expository talks, some were who-knows-what talks. I liked Moore’s and Kallosh’s talks from the first day, and Van Proeyen’s talk and Martin’s “homage” to Warren on the second day. The third day was quite interesting and I liked (and “understood”) Maldacena’s, Roiban’s and Gauntlett’s talks.

Another highlight of the conference was a beach trip to West Meadow Beach. I walked for about an hour along the shore. I collected photographed some stones, shells & seaweeds and birds like seagulls, egrets, ospreys, plovers & terns. I also saw horseshoe crabs for the first time and they look like toy tanks with tails!

More photos from this trip are shared in the following album. Till next time!

Stony Brook Album

End of an Era in Technical Computing

Cleve Moler, Inventor of MATLAB, Cofounder of MathWorks, is no more. I was quite stunned because I follow his blog and it felt like just a couple of weeks ago, he had published a post about oscillators!

I started using MATLAB in the second year of my undergrads (2008-09) and have not stopped since then. I didn’t know it had an inventor (like C or C++ had) for a long time, maybe I got to know about him after I started my graduate studies! When I first saw Cleve Moler’s Photo, I thought, “Sure, he looks like someone who could do numerical computing for a living!”. After that, at some point, I started following his posts (and those of other MathWorkers, too) and learning the “secrets” of MATLAB.

Even if MATLAB does not play a significant part in my research, it is still there prominently on my laptop, powering an “accounting” program, a (two) SuDoKu solver(s), a couple of image manipulators, a few games, and long forgotten GUIs that had once made me “famous” at IIT KGP! Whenever I get stuck in some research problem, I start up MATLAB and tinker with my existing programs learning new ways to do old things efficiently or make new programs after having learnt new things to try. It plays a crucial role in refreshing my grey cells and prepares me mentally to go back to my research problems with greater enthusiasm to solve them “this time”. Because it has never happened that a problem has remained unsolved in MATLAB, at least the programming part!

So, Thank You Cleve Moler for MATLAB. Your impact will be remembered for eons to come. Rest in peace.

Numerical Computing

Relativity of Coffee…

I came across a café in Bengaluru called Coffee Chemistry stylized and shortened as “C²” read as “C Square”.

My eyes then fell upon a cup-shaped prop (more like an outline of a prop) outside the said shop, which gloriously displayed (arguably) the most famous equation E=MC² and postulated it to mean “Energy = Milk × Coffee²”! What a cheap way to invite physicists (and chemists too I guess).

As a physicist, I have an issue with this “incomplete” equation because in modern notation the “full” equation reads “E=γmc²” (γ is read “gamma”). I am not going to talk about the physics and/or the rationale behind it… maybe another day! I guess the café owner could not get the artisans to fit something like “Energy = glass × milk × coffee²” on the prop!

As a high energy physicist, I have even more pressing concerns because in natural units “c = 1” and the equation just reads “E=γm” with no coffee in sight anymore! Will I be satisfied with just a glass of milk in a café?

Anyway, I leave you with some Physics behind the formula and you will know exactly what “γ” stands for.

For γ

Sketchbook is Truly Over!

Yes, this sad announcement is all there is for this post…

Sketchbook’s official end was more than 6 years ago, bookmarked by this post.

Its scanlation ended just yesterday. For those interested, here’s a sneak peak (the picture below is clickable!):

Finally, I hope something similar happens for

Scorebook

Feeble February

The weather has been all over the place this month. Mornings and Evenings are quite chilly but the rest of the day is quite warm. I seem to turn on the fan for 10 minutes every hour or so. There were again a few weddings this month but I didn’t attend any as I did in November because Sakura had a few Olympiad exams this month and her final exams for class 3 start next week. You may wonder why I did not go alone as I did in November! Well, I wanted to help her “revise” regularly this time. Anyway, it seems she did as good/bad as last time so my “help” may not have helped that much. Or, maybe it “helped” to maintain that level of consistency!😆 We did take a weekend trip to Kochi before the exams, so there’s that too. And remember Fort Kochi is not a Fort!🤯

I have also been programming the past few couple of weeks and the result of that is here. The actual code and stuff is accessible directly on GitHub. It is basically a card game that became well-known as a nontrivial programming problem in a contest organized by MathWorks last year.

Out of the blue, 5 chapters of Sketchbook dropped this year after a gap of nearly 3 years! And these did not disappoint. Two sample strips about cooking food are perfect:

Lastly, I listened to a “new” poet this month. I was amazed at his choice of simple words which packed a brilliant punch to where it mattered! This is again one of those untranslatable Ghazals so I won’t even transcribe it in English. But I will try to explain it below, though I don’t think I will do it justice.

राह बदलूँ के क़ाफ़िला बदलूँ
इससे बेहतर है रहनुमा बदलूँ

दर्द जाता नहीं ए चारागर
रोग बदलूँ के मैं दवा बदलूँ

फिर वही खुद से रोज़ का झगड़ा
खुद को बदलूँ के आईना बदलूँ

अब कोई प्रार्थना नहीं फलती
शब्द बदलूँ के देवता बदलूँ

ज़िंदगी की रदीफ़ रूठ गई
बहर बदलूँ के क़ाफ़िया बदलूँ

–दीक्षित दनकौरी

The whole Ghazal is about dilemmas in various situations, where one has to choose one option or the other. This Ghazal is so structured that the first and last Sher themselves open up dilemmas in similar situations but with contradictory options! That’s what makes this a great Ghazal. So the first Sher asks in its first line whether to change one’s path or one’s company (caravan); only to wonder in the second line if it’s better to change the leader. The second Sher complains to the doctor that the pain does not subside; and wonders whether to change the disease or the medicines. The third one is upset about fighting with oneself; and wonders whether to change oneself or the mirror! The fourth one is so profound as to notice that no prayer is being answered; and wonders whether to change the words or the gods! The last Sher contains quite a few technical terms related to Ghazals (refer to this post for their technical meanings) but they all have “normal” meanings too, so in essence, this Sher is full of श्लेष अलंकार (Puns) raising it to the highest level of poetical beauty I’ve ever witnessed! Here is what I think are its dual meanings: 1. My life’s refrain (रदीफ़) is “upset”. Should I change the meter (बहर) or the “rhyme” (क़ाफ़िया)? 2. My life’s co-travellers (रदीफ़) are upset. Should I change my ways (बहर) or the followers (क़ाफ़िया)? What a reversal of viewpoint compared to the first Sher: there, the leader seemed to be the problem and here, the followers! To appreciate the beauty of this Ghazal fully, here is Dixit Dankauri reciting it in full (starts around half-time):

Dixit Dankauri, Jashn-e-Adab, 2025

His previous recitals are also worth listening to: 2019, 2021 & 2023. One more on the occasion of

Gopaldas “Neeraj” Birth Centenary 2025

Happy New Year!

The first month of the new year is about to end so I might as well put up the first post before it is too late.

Let me start with the last month of the last year, first. We went to Taipei after nearly 8 years and met with my “old” colleagues who seemed to have aged not even 8 months! But in that period of time, I have an 8-year-old kid tagging along with me and I may as well have aged 18 years with my balding face, rotund shape and aching skeleton. Literally! Apart from that, it was a great trip. We (re)visited some of my old haunts like NTU (of course), Kapok Vegetarian Bakery, Da’An Park, Maokong Gondola, etc. These places have changed quite a bit. One example of an extreme change (which was disorientating at first) was the 4-way square flyover bridge over the Da’An park intersection was nowhere to be found! Anyway, Sakura seemed to like these places. In other news, we almost lost Sakura’s ear-warmers on one trip (THSR to Taichung) and almost lost her on another (National Palace Museum)… These are stories for some other time! And so a weeklong trip came to an end with a visit to the Taipei Zoo where we witnessed South American animals in flesh for the first time. We refrained from doing the “tourist-y” thing and climb Taipei 101 again this time. But somebody doesn’t care about that!

 

Let me end with the first month of this new year. Not much noteworthy has happened, though. We watched the Republic Day parade live for ~3 hours today. Sakura enjoyed the floats and stunts by the CRPF officers & military jet pilots. Though, she missed the coloured jets those jets didn’t spray! Anyway, Happy New Year once again to all the readers of this Blog. Hope you learn and grow beyond your expectations this year…

Happy 2026