Artwork by Saurabh Shandilya
From conversation on:
Feb 17, 2021
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Sensors and instruments are an engineer’s extra set of eyes and limbs reaching into domains they cannot reach physically, be it the low pressure, oxygen-less environments of space or the high pressure, no light regions deep under the sea. To design an instrument is no easy feat, with hours of precision engineering and skill going in to construct the most elegant solution to the problem at hand. While the field of instrumentation finds relevance in the everyday lives of the whole community at large, a plethora of details often go amiss. In our conversation with Dr. Anoop C.S, an Associate Professor at the Indian Institute of Space Science and Technology, we discussed the elaborate details and processes that go into designing sensors and circuits that are employed in a wide spectrum of applications ranging from medical sciences to the space industry. While also delving into the details about his experiences, ideas and his unique methodology that he applies to both his research work and his teaching.
Concepts may come and go, as and when we talk. Ideas may materialise even while walking across a corridor, but it finally depends on you to pursue what you want.
ABOUT THE GUEST
Dr. Anoop C. S. Associate Professor, Department of Avionics, Indian Institute of Space Science and Technology, Thiruvananthapuram
Dr. Anoop C.S. is a researcher who specialises in the field of Instrumentation, analog signal processing and sensor technology development. He completed his undergraduate from the College of Engineering, Trivandrum and went on to take up his PhD as well as postdoctoral work at the Indian Institute of Technology, Madras. Following which he joined IIT Kharagpur as Assistant professor before taking up his current post at the Indian Institute of Space Science and Technology, Trivandrum. Dr. Anoop C.S. has worked elaborately in varied facets in his field of expertise like sensor design, signal conditioning, analog-digital interfaces and direct digitizers, to name a few broad directions.
Transcript
Shreya Mishra (Host 1) :
Welcome to another episode of Zeroing In, I am Shreya Mishra and hosting this episode with me today is Aman who is currently pursuing his Bachelors’ degree in Avionics in the Indian Institute of Space Science and Technology, Trivandrum. Today we are in conversation with a researcher who specializes in the field instrumentation, analog signal processing and sensor technology development. He completed his undergraduate from the College of Engineering Trivandrum and went on to take his PhD as well as Post doctoral work at the Indian Institute of Technology Madras, following which he joined IIT Kharagpur as assistant professor before taking up his current post at the Indian Institute of Space Science and Technology Trivandrum. He has worked elaborately in varied facets in his field of expertise like sensor design, signal conditioning, analog-digital interfaces and direct digitizer to name a few directions. When these fields find relevance in the everyday life of the whole community at large a plethora of details often go amiss.
In our conversation with him we discuss the elaborate details and processes that go into designing sensors and circuits that are employed in a wide spectrum of applications ranging from medical sciences to the space industry, we also talked about his experiences, ideas and his unique methodology that he applies both to his teachings and his research work. A very warm welcome to Dr. Anoop C.S.
Shreya :
So, once again, thank you sir for joining us today.
Dr. Anoop C.S. :
Thank You, thank You, thanks for welcoming me.
Shreya :
Of course sir! So we’d like to begin the discussion by a very fundamental question, that is, what are your ideas about your field of work, and basically would want to know where did this whole fascination in your life pitch from and later on, in fact went ahead to become your career choices. Can you just throw some light on that bit?
Dr. Anoop :
Uh so, for that I have to go a little bit back in time maybe 15 years back. So that time 15 years back I was a maybe 12th standard student, something like that. So, I was good at mathematics, uh.. but then the trend is to go for engineering. Okay, I also went for engineering. Uh so that time as you told I joined College of Engineering Trivandrum. But, so in that time this preference, the order of preference was Electronics, Applied Electronics and Instrumentation and then computer science in that particular college where I studied.So I didn’t get in Electronics and Communication, so naturally I went for Applied Electronics and Instrumentation. So, that was one starting point where I was getting introduced to instrumentation. So, it was not like by my choice, it was maybe some kind of an accidental or something like you can call it and later uhh like I found this areas to be interesting, but I should say that during my four years of undergraduate curriculum I was more interested in some other subjects than instrumentation to be very frank, I was interested in subjects like control systems, digital signal processing etc. Because they were having more relationship with mathematics. As you know instrumentation is a subject which is not that much related with mathematics. But actually always instrumentation has attracted me than me getting attracted to instrumentation. So the thing is that, that time we had something known as mini project and main project. So, I had done these mini projects and main projects on the field of instrumentation but they had some control system components as well. So, basically that was because the availability of topics was like that etc. But, then I should say that the real, so-called, fascination for the so-called instrumentation developed when I joined IIT MAdras. There also I had applied maybe for control system. Control system was my first choice and instrumentation was my second. But, after getting there I had a discussion with my then-future guide. Then he showed me some works which he had done maybe in instrumentation electronics etc. So, that point I was really kind of fascinated towards electronics and instrumentation, and from that point maybe that was in 2010 around July, so, so front that point till now I am working on different areas of instrumentation.
Shreya :
Okay. So, sir, like now that you tell me that there is this fascination from like underlying fascination of mathematics that you always carried and, but you could not directly pursue it. So, would you say that maybe in every project that you take up and every research field that you take up one by one. You always look for this underlying essence of mathematics. Or, you know where this comes out the most sort of a thing. Is there?
Dr. Anoop :
Yeah yeah I, I always have a uh.. Like you told I like mathematics very much but somewhere in the way I lost, I mean I was being diverted away from the mainstream mathematics, but I do apply mathematics. See I, although my research field is applied electronics and instrumentation, I also do a lot of applied mathematics. So applied mathematics can be simple enough but I feel the mathematics concepts which was, which is, which is relatively solid for me had helped me a lot to be different from other researchers in instrumentation. So, that way it just helped me a lot.
Shreya :
Uhhhh. So sir, just a tiny question here, one more, like uhh when you look at, basically when you’re planning to design a sensor for example, so there is a plethora of technologies and various fields that you can like, techniques that you can employ to actually create a sensor and there are multiple components that can be used. So, how do you go about this entire process, like choosing the right kind of component or the technique and where does the intuition for you lies in all of this.
Dr. Anoop :
Yeah So, sensor design is a very challenging task, first of all I feel that sensor, as sensor should be designed from the scratch only if there are some issues with the commercially available models, okay, commercially available sensors for that matter, So I feel if you are having a solid problem where we have to develop a senor, the first thing is to sit down and make a mechanical drawing of the sensor unit okay, how we can maybe integrate, the, our sensor unit with an available application. So, we have to do some kind of a mechanical modeling plus an electrical modeling because finally we have to get an electrical signal out. So, after that we have to, okay, basically my flow is something like this. I am an electrical or an electronics engineer. So, once the mechanical design of the sensor is ready, I will try to work upon their electrical equivalence, aerospace people may disagree, but I will try to as soon as possible, we get, I get a mechanical design I will try to come to my comfort zone that is electrical. So, there comes a little bit mathematics, okay, whenever we are working with electrical equivalence, we have to bring in some analogies and mathematical stuff. So, one that is, electrical equivalent is done or then we will get a fairly good idea about how the sensor will behave, what will be the characteristics etc. So, then we will be able to improve the sensor and maybe improve the mechanical features etc. So, this will be followed by some simulation studies, of course, making hardware prototypes, testing, miniaturization etc etc. But the most important thing I feel is the initial design and its conversion to maybe an electrical equivalent.
Murala Aman Naveen (Host 2) :
Yes sir. Listening to the way you go about with your work and the way you did work with the sensor design it is pretty evident that you have an inert love for this and, as we have gone through your research process and all the publications you have gone through so far let us start off with one certain thing that has been protruding out very evidently and this is very specific word called an angle sensor or and angle transducer. It has started off from the time you have been working on your PhD and it has been continuing till now as one of your very inherent work and you have been working on it with a lot of rigorousness and with a lot of love. So, would you like to throw some light on where this interest has sparked in you, where you look at two intersecting lines and then you find it interesting. Could you tell us what and how did you go about with this?
Dr. Anoop :
As you know in 2007, I think uh, if you look at the nobel prize, the nobel prize in 2007 physics was awarded to Albert Fert and Peter Grunberg for the invention of giant magneto resistance. Okay, so the giant magneto resistance technology was very upcoming one. And then new angle sensors based on that particular new technology was just being out in market. So, we were trying to use that particular technology towards this industry problem. Then we found out that there is a mathematical problem there. Naturally, I got fascinated. So the problem was something like this, sensor was giving a particular nonlinear behaviour, inverse cosine behaviour and I had to make a circuit to linearize it. So, then I was like, I should say, I had spent about two and half weeks to get an idea which can do that particular function. Then, it started coming and then we slowly incremented that work and finally I made it maybe, industry ready. So after maybe one year or so, again the industry partner visited us, our labs, then they told, “Okay your works are very good but, then it has a small problem that it will not suit the mechanical constraints posed by our application,” by their application. So, then we, in the second part of my PhD problem I developed some sensors and electronics for that particularly for the through shaft angle sensing problem. But, then, first part was not fully completed. So, once I was out of my PhD. So I took up, I was in IIT Kharagpur, that time one PhD student had joined me. So, then I continued with the first part of my, that PhD work and that is seen across uh in the form of many publications which has come out recently. So that student has also passed out, uh finished his PhD very recently and that way we had got a number of publications but we like, the point is that, that is a very, I should say very interesting area, uh where, which has a number of applications even in robotics or automotive sector, aerospace sector, etc. So I mean, so I should say somewhere now it has got saturated, so that is why I am going to kind of moving on to new fields as well. Okay! So this kind of repeated nature of angle sensors or angle transducers whatever you call it was seen partly due to an industry requirement and partly due to my interest in uh.. Like mathematics that problem of inverse cosine maybe I should say.
Aman :
Yeah. So yeah, the repetitive nature was very evident in your publications and like, as we went through all your publications we’ve seen that you’ve tried to employ multiple techniques in understanding how can uh work with an angle transducer, so could you elaborate the certain process that you went through and how, where, what was your reasoning behind choosing multiple techniques and understanding why that working was going on?
Dr. Anoop :
Yeah So as far as one of the first part of my work which I will call the inverse cosine base work was concerned it was more about improving the circuit okay. Initially the circuit developed was sensing rotational angle until 180 degrees. So, then people, like we wanted to sense across 360 degrees, then there was an improvement. Further, there were a lot of challenges, I mean there were a lot of issue in the first schemes which was continually getting overcome with the subsequent schemes. So, that was one part, so now the, in this second part, I should say uh it was more of the so-called the sensor design which you people are referring to. So there, the job was more challenging, I was, it was like not mathematics okay. It was a lot like the selection of the right condos, the right shapes etc. So, I’m still continuing that part of the work with some help of my some aerospace colleagues but there we had to come with some interesting structures like spiral shape structures etc so that we can sense the angle. So it was a, like, I should say both parts was very intuitive for me. One was like an area which I loved a lot of much, that is mathematical modeling and circuit development. Other one was more like made me ready for the industry I should say.
Aman :
okay, yes so even this was one thing that we found out that you have a patent in this field and I would like to quote the patent, it is a “Combined Reluctance hall effect angle based sensor” which you have, which was acquired in 2013. So, could you tell us what this is and how it is evaluated for you in your current field and how do you think this has pushed you in your field?
Dr. Anoop :
So this patent was filed maybe in the final years of my PhD program before I left from IIT Madras. So basically this was, this was a project kind of a prototype that we made for that we made for that one industry partner. Patent it is very, I should, I should say is a very technically sound one and it is one of the one of a kind design which helps in through shaft angle sensing. So, it has multiple applications and it can give a range of about 360 degrees etc. So, that patent was of course very much helpful for me for maybe more for my career and maybe the further research, you know aspirations etc.
Aman :
Yes sir. So as we have seen that. Uhhh, how do I put it? You have been doing extensive research on a certain topic and you’ve been working along a lot of people, a lot of students as a researcher. So, could you talk about your current work apart from angle sensors and how you have been involved in it, could you elaborate what is the process that goes behind the doors of the lab which is not, uh, what you say, visible to a student as just a graduate student. So, could you talk about that for sometime.
Dr. Anoop :
So, So, I actually have a lot of fun working with undergraduate students, I should say that. So, if you, if you go to, go to my google scholar and count the number of papers of undergraduate students, right? There I think more than that I publish with maybe PhD students, say I am working in a different number of areas. Most of these areas was started with the help of undergraduate students and some of them have given me a lot of maturity of the products or these circuits or sensors as well. So, presently I work apart from the angle sensor work I do work on a particular very challenging topic like low current measurement, so this maybe you may not see in my publications because it’s somewhat related with ISRO, ISRO projects. So here it says, we have to measure very ultra low currents, which can be as low as 1 pico ampere or even less than that. So, so this actually we had maybe , we had maybe reached until 10 Pico ampere levels as of now, and actually one of this kind of, this electronics was like a part of the payload which, IIST sent in pslv44 c 47 mission. So basically this payload was used for ionospheric studies. So this is one of the ISRO activities we do in our instrumentation and measurement lab. So apart from that, see I work extensively for making interfaces, digital interfaces for resistive and capacity sensors. Apart from these works, I also work on a new of chaotic electronic circuit, okay, this works were again started by one of your senior students, undergraduate students, so the basic idea is to use chaos is electronics. So this chaotic nature is usually not well appreciated in other fields of engineering like aerospace or fluid mechanics. But we try to exploit the phenomenon of this chaos so that we can extract more information about a sensor or a sensing variable or to develop an analogue to digital converter etc et. So that is another work which we are doing. So this is again mathematically intensive work which I believe will bring me back to my roots of mathematics,okay. So I mean, over time I like to like slowly move to different areas where mathematics and instrumentation are closely coupled together. So I also do some other industrial relevant projects like non destructive testing using magnetic sensors, like we suppose we have to measure or estimate the cracks or fatigue in aeroplane foils or building structures etc, so we had developed some magnetic sensing arrangements which help to do such non destructive testing.
Shreya :
yes ,ofcourse. Yes sir, we went through your research and it was pretty elaborate to actually point out one thing. But I think through the conversation there is one that we can say, like you said, instead of you looking for instrumentation, instrumentation looks for you and you look for mathematics . I think that’s how it all goes.
Dr. Anoop :
yeah , I guess that’s the perfect way to portrait it across.
Shreya :
Exactly! So sir like you said, you worked in the industry as well, we went through your profile and we also learned that earlier you worked in industry and then you moved onto academia. Can you tell us what was the primary reason behind this change, why you chose to do this?
Dr. Anoop :
yeah. It’s like I was born in Trivandrum I should say, I studied in Trivandrum and I did my BTech in college of engineering, trivandrum. So I wanted to have a more, you know external exposure, okay , before doing any post, any further degrees or educational degrees. So then I got a campus placement in one of the multinational companies, then I joined there. So the work was more on networking, networking means network management systems which is again another part of electronics engineering. So the basic work is something like writing software, code for an nms -network management systems. So the work was very challenging I should say, I mean it was very time-bound work. There was a lot of development activity going on and maintenance activities also was there . So it was something like, that particular tenure of 2 years, from 2008 to 2010 where I worked in industry, actually made me face the world, I should say in the sense, we had to struggle a lot because the workload was too high. I mean there was a rapid shift from my kind of the college going easy going boy to a maybe,like a professional. So I should say, I mean we had to work maybe every 16 hours per day for maybe long, one or two years like that . So it was very, like a very kind of struggle, like it was a very but it was a fruitful , I should say. I also like the work and fortunately I was in a very good group which does a lot of work. So I should say the work was very challenging, but then I was also not Feeling that this is not my area. When during the two years, especially after the first year, after the first year we will get,I mean I got used to that field, I know what way this field is going to develop etc ,. The first year was quite challenging I should say. As you know, we will learn the most in the first year, after first year your learning curve will get maybe declined. So after first years, I was feeling something like this is not my area, I should move to electronics or control systems or like some kind of applied electronics area. So then, that is where I started preparing for masters, masters examinations etc. But I so, but the point is that I got a lot of insight into how to work, okay, although that field was not my area of interest, like how to approach a problem, like you ask now sometime back, how did you design a sensor,okay, I mean I feel that designing a sensor would be same as maybe designing a even a car or a aeroplane or a some, any other or even a software, we have to go step by step, right., Meaning some of these activities, especially in sensor instrumentation area , some of these activities are very different from each other. But that industry experience was quite invaluable for me, because I got to know how to work,,okay, how to approach a problem,how to do it maybe within a limited amount of time etc . So I should say that, that period was very, I always cherish that period, okay, and I had like still, I Always whenever I’m getting like, there were some deadlines here and in my, wherever in my organization I always look, like think back, there I had worked 18-19 hours per day, so yeah . So we’ll get a. I felt I got a lot of responsibility from that organization also. I mean ownership we have to take ownership of our component etc. But I should say that it is different from the academia experience etc. Because in academia we tend to focus more on a particular problem, and solve that problem, okay, so it is , we have to put a lot of thought process, and , but in industry it is not maybe the other way around, we have to meet the customer or the product deadlines etc.
Shreya :
hm yeah, that is true . So sir I understand that industry was pretty , we can say challenging and hectic for you as well, but I also see that through this conversation and through your work, that you have had a love for challenges. I mean wherever you see that it gets more challenging, you choose to take it up rather than moving onto the next thing. So can you tell us ,like, being industry being challenging, but you decided to move onto academia where you could have also been actively part of the research and not been a professor. So can you tell us what motivated you to become a professor?
Dr. Anoop :
see I was always interested in teaching, okay,this is something which came to me maybe sometime in engineering, maybe UG 1st year something like that , so, I mean maybe some engineering , some professor asked me to teach something , then I taught, I think the topic was mass spectroscopy if I’m not wrong. So I taught infront of a class of 60 people. So people were telling you are teaching well,okay, so then I thought okay this is good, then maybe after that I had taken many lectures, maybe 6 or 7 lectures throughout my fourth year, this curriculum, then people are telling me you are taking well, something like that they were telling. But it had some issues, my board writing, writing on the board was not very good as you people will know, I handwriting is not that ,you know, clean etc but still people were telling this style is good, okay, then I was further encouraged to take teaching. I should say I had taken many classes as a teaching assistant in IIT Madras so again that also motivated me and then when I was thinking back, so , I think that I used to, when I was a student like many of you, I used to not only listen to the lectures okay, listen all the technical content, I think I used to see their way of teaching also, so now like , now when I think back some of the styles or teaching methodologies which I am adopting are very closely, like, borrowed from my previous professors or something like that . So , so I like teaching and so yeah, that is it. So I wanted to teach, but then I felt that research will help me to teach better,also research will help me to teach better, because they both are very tightly coupled together, so like if I do research in a particular field, I'll Be able to teach better in that field. So that is why, I felt taking up the role of a faculty in a reputed college will be one of the best options for me. Anyway I had some years of industry experience,so that is why faculty position was better for me I thought.
Aman :
yeah, yes sir. Like as we have been students of you, we know how you portray your love for teaching with the way you prepare yourself,the way you come up to the class and the way you teach is very intriguing for us and it keeps the students mind glued to the black board or the way you're teaching. So, could you tell us about how you go about as a professor, that day how you prepare yourself, could you explain a little bit about your teaching methodology and why do you go about in this way.
Dr. Anoop :
Okay, I mean I feel that,like to teach a particular concept or a topic, we should have a firm grip on that subject or topic and we should think like the audience, who is a student, okay so whenever I teach something, whatever be it , I used to think whether I will understand at your age or at the student’s age, if I was at the student’s age. So and more importantly , to be very Frank, when I was , when we study something, we generally take some assumptions. But I, one of the main agenda or main points for me, when I started my teaching career, was to remove those assumptions, okay, I didn’t want to assume anything. I wanted to remove the assumptions, this was especially challenging for me, during my initial classes, okay, because these assumptions even in textbooks etc, they tell, assume that or consider that this is the fact, but to remove that, those assumptions, it was very difficult for me . So, there were times in , especially when I was at IIT Kharagpur, my previous tenure, that I had to spend more than one and half weeks to prepare for one lecture hour, okay, so we,that time of you look , if you look back more closely at my research profile, my two years at IIT Kharagpur from 2014 to 2016, I had not, do not have much publications, research publications. That two years was kind of, the years where I focused very much on teaching, okay and so I mean my teaching methodology, I should say developed at IIT Kharagpur, to be very frank, so I used to overheat the classes of very reputed professors who have more than 30-40 years of experience. I used to sit in their classes and I used to listen to them, and so and apart from that I used to, I also borrowed some of the styles of my previous teachers ,okay ,if starting from maybe even school level, my mathematics teacher, Engineering my teachers, my guide , supervisor etc. So my teaching methodology is kind of a combination of all these things, whatever I feel optimal I have taken from it and I also feel that ,like we should have a sufficient modulation while we teach . We have to stress on some points and stress less on other points etc, so there are many like Teaching methods, maybe like which I had, maybe like go through my experience developed but it’s more like we should have the right preparation, the right kind of preparation so that we can face the students and we can face them with confidence.
Aman :
Sir, like the amount of effort you put into this, you have some expectations from yourself, the way you come across, the way you teach. So do you similarly have any expectations from the students?
Dr. Anoop :
Till date, see, I have taught classes of 6 people, I have taught classes of 20 people in your engineering physics branch, I have taught classes of 50,55,60 avionics, and back in kharagpur I used to teach classes of 180, a huge classroom, theatre like classroom etc. Whatever be the class strength, you should, I feel a teacher should communicate well enough with the students, whether it is a back bencher or a first bencher, we should treat everyone equally, I mean like everyone gets equal emphasis and equal take home messages from the give .
Shreya :
Further, I’d like to ask if there was any other research direction that you are not currently pursuing or you always wished you had pursued but could not, probably because of time constraint or maybe you went into another line. So can you tell us about some of such research directions which you hoped you had pursued.
Dr. Anoop :
you see, as you , as you mentioned now, as you see I previously worked on a network management company, which is basically a networking software company, so now like , when you asked this , I was thinking what area should I work new, then I was thinking what about sensor networks. I mean I work on sensors and I can adapt from my previous, maybe 12 years back, those concepts. So I mean concepts will come like as and when we talk, okay or as and when , even when I walk on a corridor, some ideas will like, materialize. It depends on what to pursue and what not, right?
Shreya :
Although this is difficult to imagine , but I would really like to ask you , had the field of academia not existed, or you know taking up research ,you would have not taken up research , what else possible career path would you have chosen? I mean, but to be honest it’s very difficult to imagine you in any other setting given that how elaborate you are here, but we’d really like to know.
Dr. Anoop :
So, see , see I should say that this dream of being a teacher came in somewhere around 2006, okay, but if you ask me , maybe, maybe early 90s or something when I was a kid, what was my dream, then I used to tell my, I mean all the people whom I know then, that I used to , I want to become a scientist at Vikram Sarabhai space centre okay , I mean, maybe you can ask why, maybe it’s because my father was, had worked there for about 37 years, okay, so yeah , but, but then , like that was my childhood dream, okay, but like then after sometime our dreams get changed, modified , by 2006 or so I was always passionate about teaching.
Aman :
So we would like to conclude this session here , so before we close the session, do you have anything else to say or anything that you want to convey to the general crowd?
Dr. Anoop :
So like, this is a very good opportunity for researchers and faculty like me, to kind of expose their, maybe the other side. So I, I really thank you for inviting me for this lecture so, maybe after 10 years or so, you can maybe invite me once again, then we will see whether something has changed [laughs].
Aman and Shreya :
[Laugh]
Shreya :
This was Zeroing In with Dr. Anoop C.S. We extend our sincere gratitude to Dr. Anoop for sharing Stories about his incredible journey in the field of instrumentation and sensor development, along with British Sontakke for collaborating on those episode on behalf of zeroing in season 2, which includes Murala Aman Naveen, Kanthan Narayan, Kriti Raj, Arun S., Shaun Ethan and I am Shreya Mishra. Thank you for listening to this episode. Zeroing In is a non profit initiative by the alumni association of the Indian Institute of Space Science and Technology, Thiruvananthapuram. If you have any suggestions you can write to us on zeroinginpodcast@gmail.com or contact and follow us on Instagram and Facebook handle @ZeroingInPodcast.