Thursday, January 20, 2022

Socially Useful Productive Work. A Talking Weighing Scale for the Visually Impaired!

 Making something which is socially useful is always desirable. In my ecosystem, I don't care if I can have a car navigate the roads autonomously, using machine learning. What I care about is a weighing scale that can speak out the weight using a suitable hardware and software. Here is a project we did for helping the visually impaired students pursue science in a meaningful way. Hopefully, it will be adopted by NCERT and scaled for widespread use.


Sunday, January 09, 2022

Electronics Design Workshop - A Hands-on Course

 This semester (January to May 2022), I am teaching a course titled 'Electronics Design Workshop' to 4th semester students of ECE at NSUT. Incidentally, I had designed the syllabus for this course 2 years ago. Although it was offered for the first time last year, I did not have an opportunity to teach it. Now, I do.

The weekly schedule consists of 2 hours of lectures and 4 hours of laboratory session. Although, while the online classes are on, we do not have the luxury of face to face laboratory experience. 

Here is the syllabus:


Learning Objectives:

  1. To be able to visualize a system/product in terms of hardware and software building blocks using a project based learning approach.
  2. Learn useful mechanical and electronic fabrication processes.
  3. Learn necessary skills to build useful and standalone system/project with enclosures
  4. Learn necessary skills to create print and electronic documentation for the system/project
  5. Build, test and document a useful power supply before the mid term.
  6. Build, test and document a useful project/system.
  7. Learn various debugging tools and techniques.

Unit 1: Electronic component familiarization, Understanding electronic system design flow - visualization of system requirements, time planning using Gantt chart, schematic design and PCB layout, circuit fabrication, soldering and testing, heat sink and cooling for critical components, system wiring, building system enclosure, system testing and debugging, documentation. Documentation using Google docs, Overleaf. Documentation from firmware - Doxygen. Version control tools for documentation as well as firmware release management - GIT and GitHub. Familiarization and use of basic measurement instruments - DSO including various triggering modes, 1X and 10X probes, DMM (including CAT I, CAT II, CAT III, and CAT IV type of DMMs), LCR bridge, Signal and function generator. Logic analyzer or MSO. Bench power supply (with 4-wire output)

 Unit 2: Circuit prototyping using (a) breadboard, (b) Zero PCB (c) ‘Manhattan’ style and (d) custom PCB. Schematic design and PCB layout using EagleCAD. Gerber creation and 3D visualization for fitting. Single, double and multilayer PCBs. Single and double sided PCB prototype fabrication in the lab. Soldering using soldering iron/station. Soldering using a temperature controlled reflow oven. Automated circuit assembly and soldering using pick and place machines.

Unit 3: Electronic circuit building blocks including common sensors.  Arduino programming and use. Getting acquainted with the Arduino IDE and Basic Sketch structure. Digital Input and output. Measuring time and events. PWM. Serial communication. Analog input. Interrupts programming. 

Unit 4: Power sources and power supply regulator design. Linear and switching power supply. Transformerless power supply. Zener regulator, op-amp based regulator. 723 IC regulator. 3-terminal IC regulators. LDO and micropower regulators. Buck, Boost and Buck-boost switching regulators. Short circuit and over-voltage protection. Wireless power supply. USB-PD. Battery types and characteristics. Battery charging for lead-acid and lithium type batteries. 

Unit 5: Mechanical fabrication processes - 3-axis CNC, 3D printing, mini lathe, drilling, Laser cutting, Laser engraving etc.. 3D printing technology - FDM, SLS and SLA. 3-axis CNC operation. 2D file designing for drilling, cutting,  milling, Laser Cutting and engraving using Flatcam, Inkspace, OpenBSP. 3D file designing using Sketchup, FreeCAD, Prusa Slicer.


Suggested Reading:

  1. The Art of Electronics. 3rd edition. Paul Horowitz and Winfield Hill. Cambridge University Press. ISBN: 9780521809269 
  2. Practical Electronics for Inventors. 4th edition. Paul Sherz and Simon Monk. McGraw Hill. ISBN-13: 978-1259587542 
  3. Encyclopedia of Electronic Components (Volume 1, 2 and 3). Charles Platt. Shroff Publishers. ISBN-13: 978-9352131945, 978-9352131952, 978-9352133703
  4. Building Scientific Apparatus. 4th edition. John H. Moore, Christopher C. Davis, Michael A. Coplan and Sandra C. Greer. Cambridge University Press. ISBN-13: 978-0521878586
  5. Programming Arduino: Getting Started With Sketches. 2nd edition. Simon Monk. McGraw Hill. ISBN-13: 978-1259641633
  6. Debugging. David J. Agans. Amacom. ISBN: 0814474578
  7. Make Your Own PCBs with EAGLE: From Schematic Designs to Finished Boards. Simon Monk and Duncan Amos. McGraw Hill Education. ISBN-13 : 978-1260019193.
  8. Pro GIT. 2nd edition. Scott Chacon and Ben Straub. Apress. ISBN-13 : 978-1484200773

Laboratory Activities:

Basically, build a stand alone mini-project using Arduino (or any other microcontroller of your choice), some sensors, displays etc. The mini project should have its own power supply or battery power source. The mini-project should be properly enclosed in lab designed and fabricated enclosure which could be 3D printed or made using CNC machining. The mini-project would have a mandatory documentation report.


For majority of students who join ECE these days, it's not their first choice. If they could, they would have liked to join some CS course. However, I want to assure them that (a) it's all very much crowded in the CS stream (b) there is no dearth of programming opportunities in ECE subjects (c) at the end of the day,  a computer program needs real hardware to run, even if it's in the cloud. YOU can be that engineer who will build that piece of hardware! 

What do I expect you to build? Well, there are a kazillion things you could build. Here is a sample example. It's an AVR microcontroller based circuit, with it's very own custom designed and 3D printed enclosure. It works in two modes - in one of the modes, it displays the ambient temperature on the single seven segment display (by serially printing the three digit temperature in degrees Celsius) and in the other mode, it generates a random number between 0 and F. In the first mode, it can also be used to generate Morse code by pressing the switch or attaching and pressing Morse key to the Aux connector. You will hear the sound of the Morse code on the buzzer that you can see towards the top of the gadget, next to the red seven segment display.

The black blob next to the Aux connector is the temperature sensor (LM35). If you don't see any microcontroller, don't be alarmed. It's on the other side of the PCB, it's a SMD component - Tiny44. The power to the system is from a USB charger or USB power bank, you see that blue cable?

I am very excited to start the classes from tomorrow. Although, I wish we would get over with this third wave quickly and back to normal, face to face classes, so that my students can get real hands-on experience of building useful electronic circuits and systems.

Tuesday, April 07, 2020

A 'Teaching Instrument' - Experimental Element of Education during Lockdown.

How to ensure that experimental work can continue in such lock down conditions too?

Here is a paper written by Prof. K V Sane, with whom I had an opportunity to work with, during 1989-1992. The solution is, what he calls a 'Teaching Instrument'.

You may have already realized how the specifications of several instruments in electronics labs are way above their actually utilization. A 1GSPS/100 MHz DSO commonly found in electronics labs, hardly ever gets used beyond 1 MHz.

Today, the cheapest 3-1/2 digit DMM sells for less than Rs. 100. It is not impossible to imagine a 10MHz BW DSO front end connected to your laptop (for the display) for Rs. 250. Thus, it is quite possible to imagine a 'Lab in a Box' with a set of components etc, all for less than Rs. 1000 that may be quite sufficient for conducting experiments at home during lockdown conditions.

Getting a student to build such a 'teaching instruments' will generate an additional benefit of student involvement, skills in soldering, system design etc, which are currently sorely lacking.

Monday, April 06, 2020

Parenting an Industry in Engineering Institutes

This is an old idea I thought strongly about in the past, which is making a comeback, at least in my mind. Perhaps, it is the right time to consider it seriously, however crazy it might appear:

"If a medical college must have a hospital to function, why should it not be mandatory for an engineering college to have an industry on campus? For how long would we keep fooling the country that we are engaged in 'blue sky' research? That 'blue sky' research has no term period. Choose an industry of your choice, whatever is needed and beneficial in your region, choose the scale that you can handle. But for your own sake, choose something."

This idea will also address the concern of many academics who often defend the Indian engineering educational institutes and feel they are the victims. However flawed their defense of the Indian engineering educational institutes maybe, this proposal addresses that also.

Also, if you notice, this idea is making a backdoor entry in many engineering institutes in India already - how would you describe the so called 'Incubation Centres' if not a backdoor entry of industry into educational institutes?

However, as currently implemented, the incubation centres are flawed. The engineering colleges which are hosting such incubation centres, do not have their own skin in the game, they are merely working as landlords. They take government's grant money and use their extra space to rent to start ups. That has to stop. The engineering institutes must take larger ownership of these start ups and groom them as their own. And not just to sell off to an established company but to actually manufacture something.

Tuesday, March 24, 2020

Assistive Technologies for Visually Impaired Students

Last week, before the lock down kicked in, I had an opportunity to participate in a week long workshop conducted by Department of Education in Science and Mathematics (DESM) at NCERT. The workshop was about putting together requirements and guidelines for creating assistive technologies for the visually impaired students to visualize and enjoy science in general and to pursue science experiments in particular.

Midway during the workshop, I showed all the participants (around 20 teachers from various levels) all our embedded systems projects many of which demonstrate talking sensor ideas.
As a result, I am happy to share that I have been tasked with creating about 12 assistive sensor projects. They deal with sensing liquid, light, touch, heat, weight, color, pressure etc and to convert to sound and/or speech.

It's not only a great honor for me and my cohorts at NSUT, it is also a great responsibility. It is important that the faith that has been reposed in us, should be responsibly discharged.

I am therefore, using this platform to seek summer interns to work on these projects. I am looking for students with good 'Maker' skills together with knowledge about electronic circuit design and fabrication, embedded controllers, embedded programming and circuit and system fabrication. Please e-mail me your CV/resume as a PDF file that lists matching skill-set at: dvgadreatgmaildotcom.

Caveat Emptor: We don't know how this current pandemic will play out and whether we will have any summer vacations at all. So, please keep that in mind.

Wednesday, October 03, 2018

Posthumous Digital Picture Frame

I read the following on WhatsApp:

जब तक जीवन है ……रोज डी पी बदलिए.

बाद में तो एक ही फोटो में लटके रहना है 😂😂😂

वो भी बच्चों ने लगाई तो !!!😜😜

(While you are alive, change your DP everyday. After you are dead, there will only be a single picture on display and that too if your kids put it up!)

When I think about it, it dawns on me that it is so true! But in this day and age, it need not be like this at all. Here is a possible business idea - A posthumous digital picture frame. You purchase a plan and you start submitting your pictures to this service. Once you die, the people you name in your will, will be delivered a digital picture frame which will have all those pictures you submitted over time and they will be displayed on the picture frame cyclically!

I am very sure this a great idea and may have good demand.

Monday, October 01, 2018


As of 26th September, we are now Netaji Subhas University of Technology!

Earlier last month, on 9th September, we had visited the Centre for Education and Health Research Organization (CEHRO) office at Munirka Village near JNU and interacted with around 40 kids who had assembled to hear me speak and watch the project demonstrations that I conducted. Several of these students sent me a report of the day's activity that they witnessed, in their own words. As a follow up to that event, we invited select students from that group to visit my lab on 30th September.

This blog is a record of their visit. In my opinion, their visit was not only an opportunity to learn about tinkering, science and technology but also about being good citizens, first and foremost.

The CEHRO kids belong to very poor economic background, which is actually a very important and good reason to engage with them. I have interacted with 100s of kids from rich public schools. Kids of these schools already have good facilities available to them. Why not engage with kids with poor economic background and contribute whatever little I can?

Twenty two kids accompanied by four mentors, including Surjeet Singh (our 2012 batch alumni) who runs CEHRO traveled by  DTC bus (number 764) and landed up at NSUT around 11:30 am on Sunday, the 30th September. I managed to catch them just as they were entering the campus.

I stopped them right there and explained them that we are now a University. One kid asked what is the difference? I told them that as a college, we were affiliated to a university, the Delhi University, which had other colleges too. Now since we are a university ourselves, we will eventually have more colleges affiliated to us. So, from college to university is like going from a 'lake to ocean' difference of scale.
As we walked to the CEDT on the 3rd floor, I stopped them at the gate and explained to them the features of the CEDT. I also had an opportunity to turn the staircase lights off (at around 11:30 am), so I explained to them the need to be alert about energy wastage on street lights, staircase lights etc. and do whatever it takes to get the lights switched off or switch them off themselves if they can, in the interest of saving energy. I also pointed them to the 'Twilight Switch' that controls the lighting of the notice board of CEDT right opposite the entrance of CEDT. I explained how sunset/rise time at a given location can differ significantly from another location in the same time zone and how a computer (a normal or an embedded variety) can calculate this time and control street lights etc.
I explained to them the meaning of the name of our lab - CEDT. And how CEDT has been a mother lab, spawning more labs and activities. I highlighted Motherboard, Mothership.. the importance of Mother in our lives.

 Once inside the lab I explained what all activities we would be doing. Since some of the kids did not have any notebooks and/or pens,  I suggested that they go around the campus with Surjeet so he could show his 'alma mater' to them while I arranged for notebooks and pens for them. They came back in 15-20 minutes, ready for the activities.

We started off by showing some projects which we could not show when we had visited their place earlier in September. Also discussed a simple idea about measuring the perimeter of regular shapes as well as irregular shapes using a string. Also, various ideas of measuring larger distances using different methods such as Google maps or more accurately using something called a measuring wheel or a Surveyor's wheel.

I also mentioned about how light, which otherwise travels only in straight lines, can be bent using optical fibres. We showed them a demo of a LED coupled to a plastic fibre and the light coming out of the other end of the fibre, even though the plastic fibre was coiled.

Next, we demonstrated the magnetically levitating doll. And how Maglev trains work by reducing friction. How part of the total energy is dissipated as heat due to friction and accounts for energy loss.

At this point, we distributed the 'mini sadbhavna kit' to the students but before that, I asked them to make groups of 4-5 kids each. A kit would be shared by a group  of these 4-5 kids. Surjeet suggested that they would make the groups but I chimed that let the students themselves make the groups but ensure as much diversity in each group as possible. Since there were older girls, older boys, younger girls and younger boys, each group should have variety. Why is diversity important? Not only because our national slogan is 'unity in diversity', one must experience diversity by trying to understand the view point of others. That is done best by working together.  This breaks down prejudices and at the same time allows one to know more about others, culturally, age and sex wise too.

We left the kids with a set of rules to follow to make the groups and while doing that I noticed that they will probably be discussing things amongst themselves and some kids may keep talking and not listen to others. This I explained, is a big disrespect. Not listening to others, not giving them time and opportunity to talk, there is no bigger disrespect than that. And this is a hallmark of our current social milieu. Many TV debates as well as some debates in the parliament and state legislatures have become prime examples of this lack of personal respect that we (dont) extend to others. This must change. And the discussion around the formation of a team was a good opportunity to learn to respect for others by listening to them without interruptions.

Back to the activities of the 'Mini Sadbhavna Kit', once the kids had made 5 groups. We explained the contents of the kit. The first experiment to perform was the Homopolarmotor. Got them to cut a thin  paper strip to attach to the wood screw used in the motor and explained the importance of the magnet, the polarity of the magnet as well as the battery and to make the motor with all the 4 combinations of the battery polarity and the magnet poles.

Once everyone got the Homopolar motor working, the next project was the DC motor. This time, we simplified the construction of the DC motor and got rid of all soldering requirements. Instead made the DC motor with a pair of metal paper clips, 2 rubber bands to hold the clips to each side of the battery and the magnet stuck to the battery. We explained how to roll the coil using the thick enameled copper wire and how to remove the enamel from the wire and at which places to remove the enamel from. This part took lot of time and many groups attempted the coil a few times before they got it right. I drew lot of sketches on the blackboard as well as demonstrated with actual activity to help with the coil winding. At the end, all groups got their DC motor working and every member of the group had fun making the motor move.

By this time, it was 4 pm and time to wind up. Although the kit had one more experiment (the Faraday's law based demonstration), I thought we should do it at a later date. I reiterated the need on the part of all the participants to write a comprehensive report about the day spent at CEDT and only those who complete this report would be allowed in future activities at CEDT. Here, you can see many participants standing up explaining to others, in their own words, what all should be documented in the reports!

In the end, we all - kids, mentors, our CEDT student mentors, posed for a group photograph before bidding goodbye with a promise to meet again soon!


These are great kids! They all listened and participated with great enthusiasm. They appear to be better students than those I have had from more elite schools. Maybe, their relatively poorer financial background makes them better students compared to students from richer backgrounds! Certainly, the great alacrity with which many of them sent me reports of our visit to their office on 9th September 2018, compels me to believe that.

I wish all these kids a great future together with a promise to help them in any which way I can.