QUESTIONNAIRE
INDUCTIONS
2025
DESIGNERS’ CONSORTIUM
INDUCTIONS ‘25
ROUND 1: Questionnaire
INSTRUCTIONS
1. This questionnaire consists of four parts:
a. Physics (answer all questions)
b. Mechanics
i. Part A is compulsory for BOTH STREAMS
ii. Part B is compulsory for STREAM 1 candidates
c. Circuitry
i. Part A is compulsory for BOTH STREAMS
ii. Part B is compulsory for STREAM 2 candidates
d. Research-based (answer ANY ONE question)
2. All the sections are compulsory, and all the applicable questions must be
attempted.
3. Upload your answers into Google Drive as a single PDF document and upload
the link in the given form on or before 4th June 2025, 11:59 pm.
4. Answers must be handwritten.
5. For any clarifications or queries related to the questions, contact the respective
person given at the end of the questionnaire.
6. While submitting the answer sheet, stick to the following format.
File format: Name_Rollno_Stream-{XY}
XY – 01 for Stream 1
XY – 02 for Stream 2
XY – 12 for Stream 1 and Stream 2
7. Resources for some questions are provided on the last page.
Physics:
1. An elevator weighing 800 kg is descending at a speed of 4 m/s when both the cable and
mechanical brakes fail. To prevent a catastrophic fall, a safety system employs a copper
annular disk attached to the elevator, which moves through a fixed magnetic field generated
by permanent magnets installed along the shaft.
The copper disk has the following dimensions:
Inner radius 𝑟𝑖 = 0.3 𝑚
Outer radius 𝑟𝑜 = 0.5 𝑚
Thickness 𝑡 = 5 𝑚𝑚 = 0.005 𝑚
As the disk moves downward, the magnetic flux density changes at an average rate of 1.2
Tesla per second (T/s). Determine whether the power dissipated can safely stop the elevator
within the 2-second timeframe. Discuss the phenomenon involved and its use cases in
industries and automobiles. Use copper resistivity ρ = 1.68 × 10−8 Ω ⋅ m.
2. After joining Designers' Consortium (DC), you showcased your ability to be an exceptional
engineer and product developer. Because of it, your application to join CERN, Switzerland,
as an Electrical Engineer has been accepted. While waiting to board your flight to Geneva, the
customs team learns about your technical background at the airport and presents a challenge.
They are developing a non-contact conveyor belt monitoring system using sound waves and
the Doppler effect. Your task is to help determine the speed of the conveyor belt using only
audio equipment. Here's what you have:
a. A speaker that emits a constant tone of known frequency 𝑓0 = 1000 𝐻𝑧.
b. A microphone fixed near the belt that records the shifted frequency 𝑓 ′ due to the moving
belt.
c. The conveyor belt moves away from the speaker towards the microphone.
d. The speed of sound in air 𝑣𝑠 = 343 𝑚/𝑠.
(a) Derive an expression for the conveyor belt’s speed v, assuming the source is moving, and
the observer is stationary, using the observed frequency 𝑓 ′ .
(b) If the microphone records a frequency 𝑓 ′ = 1034 𝐻𝑧, calculate the speed of the conveyor
belt.
(c) Later, customs informs you that no object can be placed on the belt for safety reasons. You
propose clapping your hands near the belt and recording the reflected sound (echo).
Assuming the conveyor reflects the wave like a moving surface, derive an expression for
v using the Doppler shift for reflected sound waves.
(d) What limitations would this acoustic method face in a noisy airport? Propose at least one
signal processing technique to mitigate these issues and improve frequency shift detection.
3. The transmission line model, typically used in electrical engineering to describe voltage wave
propagation, is also applied as an analogy in other wave-based systems, such as ultrasonic
acoustics. In these cases, acoustic impedance plays the role of electrical impedance, and wave
reflection and transmission occur at boundaries between media. In a biomedical setup to
estimate intraocular pressure (IOP) non-invasively:
An ultrasonic transducer sends a wave through air toward the eye's surface. Some of the wave
reflects due to the impedance mismatch between air and eye tissue, and a receiving transducer
captures the reflected signal.
The reflected-to-incident wave amplitude ratio behaves analogously to voltage reflection in a
transmission line. The amount of reflection depends on the eye's internal pressure, which
changes its acoustic impedance.
𝑚2
𝑍𝑎𝑖𝑟 = 415 𝑘𝑔 ∙
𝑠
𝑉𝑖 = 1.5 𝑉, 𝑉𝑟 = 0.45 𝑉
𝑍𝑒𝑦𝑒 = 415 + 5.3 ∙ (𝑃 − 15)
Calculate the IOP of the eye. Also, describe with equations, the purpose and usefulness of
transmission line models in nano to mega range scales.
4. After joining ISRO’s Martian Atmospheric Engineering Division, you're stationed at a
research base on Mars to assist in developing a self-cleaning solar panel system. Dust is a
massive problem, so you're exploring using liquid CO₂ droplets that clean surfaces by rolling
across them. However, one problem arises: the panels heat up under sunlight, reaching
temperatures high enough to trigger a Leidenfrost-like phenomenon, where droplets levitate
on a vapor cushion and fail to clean effectively.
(a) Explain the Leidenfrost Effect, including how the vapor layer forms and its consequences
on thermal contact and heat transfer between the surface and the liquid.
(b) During testing on Earth (simulating Martian pressure), a 0.05 g droplet of water is
deposited on a titanium plate heated to 300 °C in a vacuum chamber. Thermal imaging
shows that the heat transfer rate through the vapor cushion is 60 W. Given: Latent heat of
vaporization of water = 2260 kJ/kg. Assume constant heat transfer rate and negligible
conduction/convection beyond the vapor layer. Estimate the time it takes for the droplet to
evaporate entirely.
(c) You’re now told that the vapor layer is not stationary. In reality, the vapor layer flows
outward radially under pressure buildup, forming a quasi-laminar film that affects heat
flux. Given:
Vapor layer thickness 𝛿 = 100 𝜇𝑚
Vapor thermal conductivity 𝑘 = 0.025 𝑊/𝑚 ∙ 𝐾
Surface temperature 𝑇𝑠 = 300℃
Droplet boiling point 𝑇𝑏 = 100℃
Using Fourier’s law of conduction, estimate the theoretical heat transfer rate across the
vapor layer and compare it to the given 60 W. What factors could explain the discrepancy,
if any?
(d) Given the lower atmospheric pressure and different boiling point of CO₂ on Mars, explain
whether the Leidenfrost effect would help or hinder surface cleaning with liquid CO₂
droplets on solar panels. Propose one engineering design modification (geometry, material,
or control strategy) to suppress or exploit the effect for maximum cleaning efficiency.
Mechanics and Design:
Part A: Compulsory for ALL:
1. Given the 3D model in the image below, perform a comprehensive analysis to determine the
optimal build orientation and support strategy for Additive Manufacturing (AM). The study
should identify the best build orientation to minimize support structures, ensure dimensional
accuracy, and reduce post-processing. Specify the type of support structures required, the
appropriate rim or elevation method (such as brim, raft, or skirt), and recommend the base
plate temperature settings for each material: Aluminum Oxide, PLA, and Photopolymer
Resins. Additionally, recommend the most suitable AM process for each material, justifying
your choice based on material compatibility, surface finish quality, and cost-effectiveness.
Finally, estimate the print time for a model with a volume of 1000 mm³ and 15% infill for a
FDM machine of your choice.
2. A mechanical linkage device is mounted on the roof of an electric train to maintain continuous
contact with the overhead catenary wire and draw electrical power. This device consists of a
system of linked arms arranged in a parallelogram, allowing vertical movement while keeping
the contact strip parallel to the wire. During operation, the device must adjust dynamically to
variations in the height of the catenary wire caused by track undulations and changes in train
speed.
However, mechanical wear and deformation of the linkage arms can affect the reliability and
performance of the system. Understanding this mechanism's forces, motion, and equilibrium
conditions is crucial for designing durable and efficient systems. Based on the above scenario
of the linkage device used in a train, answer the following questions related to the basics of
the mechanics of machines:
a. What type of mechanism is used in this linkage device? Explain how this mechanism
maintains the contact strip parallel to the overhead wire during vertical movement.
b. Discuss the degrees of freedom (DOF) of this mechanism. How do parameters like link
lengths, joint types, and constraints influence the motion and stability of the arms?
c. Describe how to analyze the static equilibrium of the arms when the device is pressing
against the overhead wire. What are the main forces and moments acting on the linkage?
d. Suggest design changes that can help reduce mechanical wear and prolong the service
life of the mechanism.
Part B: Compulsory for Stream 1 Candidates:
3. In Finite Element Analysis (FEA), the quality and type of mesh significantly affect the
accuracy and efficiency of simulation results. Different geometric features of a mechanical
component require tailored meshing strategies.
a. Explain why sharp corners, fillets, thin walls, and large flat surfaces each demand
different meshing approaches in FEA.
b. Identify and describe different types of finite elements commonly used in FEA. For
each geometric feature mentioned above, specify which elements would be most
appropriate and explain why those elements are best suited for modeling those features.
c. Sketch a suitable mesh for the provided image.
4. Imagine you are an aerospace engineer at a leading aircraft manufacturing company. During
a flight, one of your commercial aircraft recently experienced a structural failure in its wing
spar. The investigation revealed that the wing spar was produced using traditional casting and
conventional welding techniques. Why do you think the reason for failure is due to traditional
manufacturing?
Given this incident, how could the use of advanced manufacturing technologies, such as
Additive Manufacturing and Automated Fiber Placement (AFP), have prevented the structural
failure of the wing spar? Provide specific examples of the benefits these technologies offer
over traditional methods.
5. X is building a compact motorized control knob for a device interface. The challenge is that
the motor cannot be mounted directly above the shaft due to a height constraint. Instead, it has
to be placed to the side of the shaft and powered through gears. Additionally, to allow manual
control, the knob is designed as an internal gear that engages with the gear system when rotated
by hand.
To ensure a consistent user experience, X wants the motor-driven gear system to turn the shaft
in the same direction as the knob (Equal rotational speed and no reversal of rotation between
knob and shaft).
You are tasked with designing the gear train that connects the offset motor to the shaft, while
keeping the system compact, functional, and satisfying the required constraints.
Design a compound gear train using an internal gear setup so that:
a. The shaft can be turned manually via the internal knob.
b. The motor still drives the shaft in the same direction and at the same RPM.
c. The gear train remains within a 6 cm × 6 cm footprint.
Provide a mechanical drawing (or a labeled schematic) of your proposed gear train and justify
how each gear meets the design constraints.
6. For the repetitive truss whose basic building block is shown in the figure on the right, obtain
degrees of freedom (DoF) by counting.
Circuitry:
Part A: Compulsory for ALL
1. You are asked to design a mobile phone power adapter that steps down a 230V AC supply to
a constant 5V DC output suitable for a smartphone rated at 5V, 20W.
In your design, the output voltage must remain strictly constant at 5V, regardless of any input
supply or load behavior variations. Maintaining this continuous voltage should minimize
internal losses and avoid unnecessary heating in any part of the adapter.
To test performance, the mobile phone is charged using two different adapters:
Adapter A: 5V, 15W
Adapter B: 5V, 50W
You observe that the adapter becomes hot in one case, and the phone heats up in the other.
Explain which adapter is used when? Explain the phenomenon involved and update the adapter
design to charge the mobile efficiently.
2. X is tasked with designing a microcontroller-based embedded system using the following
components:
LM35 Temperature Sensor: Requires one analog input pin to read temperature data.
DS3231 Real-Time Clock Module: Requires two digital pins for communication.
24LC512 EEPROM: Requires two digital pins for communication.
0.96" OLED Display (SSD1306): Requires two digital pins for communication.
X’s selected microcontroller provides only six usable GPIO pins, and one pin must be reserved
for a critical interrupt-driven input signal, leaving you with only five available pins for
peripheral interfacing.
Given that the total required pins for these peripherals is 7 (1 analog + 6 digital), X currently
does not have enough available GPIOs to connect all devices individually. How would X
redesign or restructure your system to successfully interface all four components with the
limited number of GPIO pins available? Propose a technical solution that allows X to connect
all peripherals without removing or replacing any. (Hint: A shift register is a simple way, but
life is never that simple.)
Explain how this solution works and how the devices would be connected and managed.
Part B: Compulsory for Stream 2 Candidates:
3. Have you ever wondered how a knob can rotate endlessly and still know exactly where it is—
without any clicking sounds or parts touching each other?
In one project, a small motor was turned into a precise and smooth control knob using a special
kind of sensor placed underneath a tiny spinning magnet. Surprisingly, just putting the magnet
a bit off-center made everything unstable!
a. What kind of sensor makes this “magic” possible?
b. Why is it better than the usual types of knobs or encoders for smooth, continuous
rotation?
c. Why does it misbehave when the magnet isn’t positioned just right?
4. You’re building a line-following robot for a contest and connecting two small DC motors
directly to the Arduino’s GPIO pins. During testing, the Arduino randomly resets, the motors
behave oddly, and one GPIO pin heats up and stops working. After some digging, you discover
you’ve missed a crucial part that should always be used when controlling motors from a
microcontroller. What is this missing component, why is it necessary, and how does it work?
You have successfully learnt all about it, but cannot buy it at the last moment. Build it on your
own with the available basic electronic components.
5. You're trying to build a knob that doesn’t just rotate freely like a fidget spinner, but feels like
a real knob—one that clicks into place at regular intervals, like a fan regulator. You’re using
a smooth, frictionless gimbal BLDC motor with an encoder, controlled via an Arduino or
ESP32. But the motor, when powered, doesn’t offer any of that “clicky” feedback (What do
you think will be the case when it is not powered?). How would you create these artificial
detents using the motor without adding mechanical notches or gears? How would the system
sense the knob’s angle and apply force at just the right time? Finally, what parameters could
you tweak to make the feedback feel sharper, softer, or more realistic?
6. You've successfully built a pulse induction-based landmine detection circuit on a breadboard,
earning accolades and prizes across campus. As product designers, you're eager to turn it into
a proper, manufacturable product. With that in mind, you design a PCB layout in KiCAD and
approach Mr. Kasturi from AK Tronics—the only person in Trichy who fabricates single-layer
photo-positive PCBs by hand. However, he becomes visibly frustrated upon seeing your layout
and insists you rework it entirely.
What might be the issues in your PCB design that triggered this reaction? (Hint: He mentions
something about Design Rule Check and the different physical types of devices used.) Also,
explore various methods available for PCB fabrication. Which ones are feasible to carry out
within your institute?
Research-based Questions:
Choose any ONE question; resources for both questions are provided on the Resources page.
1. You are provided 60 LEGO blocks and a 20 × 10 grid space, where each cell can accommodate
a maximum of one block. Based on the given load and support conditions (refer to the image),
design a structure that efficiently transfers the applied load to the supports. The goal is to
maximize the structure's stiffness, thereby minimizing deflection, using no more than 60
blocks.
The structure must be continuous from the point of load application to at least one of the
supports. You must design the structure using any suitable approach and justify your decisions
with clear, well-labeled diagrams. Utilize any engineering tools or software available to you,
and attach all resources, models, simulations, and results with your submission. (Consider
exploring mathematical models that use density distribution, such as topology optimization.)
2. Imagine you are part of a team developing a low-cost prosthetic arm for people in rural areas
with limited access to advanced medical devices. The objective is to enable the prosthetic to
respond to muscle movements from the residual limb by detecting muscle signals.
You purchase electrodes and place them appropriately on the muscle to capture the signals.
However, you find that the acquired signals are buried in noise.
After researching, you and your team discover that a specific sensor module is typically
required in conjunction with the electrodes to obtain clean, discrete muscle signals.
Unfortunately, this module is too expensive to include in the final product if the prosthetic
remains affordable.
a. Why does connecting the electrodes directly to the microcontroller’s analog input fail
to work effectively? Why is the sensor module necessary?
b. What key analog signal processing stages are needed to convert raw analog signals into
clean, usable data for controlling the prosthetic arm?
c. Since the sensor module is too costly, design a sensor circuit from scratch using discrete
blocks such as amplification, rectification, and filtering. (Provide a proper circuit
diagram using components like op-amps, diodes, resistors, capacitors, etc. Bonus points
for detailed schematics.)
After building your sensor circuit and interfacing it with the microcontroller to read analog
values, you still find that the measurements appear random and individual samples are not
meaningful. Upon consulting your mentors, they suggest applying DSP (Digital Signal
Processing — not "Degree Stopping Paper") techniques.
d. Research and explain why digital signal processing is still necessary even after
performing analog signal conditioning.
e. What digital signal processing techniques can obtain clean, physically interpretable
results from the sensor data?
Once you implement these techniques, you obtain meaningful time-varying signals
corresponding to different palm movements and grasping patterns. You attempt to find
biological or theoretical models that relate muscle contraction voltages to specific grasping
patterns, but find that no established model exists. Thus, you are left with gesture-labeled timeseries data and must use this to categorize different grasping patterns.
f. What machine learning model would be suitable for this task, and how can time-series
data be used effectively in this model?
g. Create a block diagram showing the data flow from signal acquisition to the
classification of grasping patterns.
h. What would be the limitations of using a feedforward neural network for this
classification problem?
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For any doubts, contact the respective people for the respective sections:
•
•
•
•
Physics: Monesh +917904829577
Mechanics and Design: Anirudh +916300258616
Circuitry: Rajaram +918124680547
Research-based: Hari Kishan +917674865996 and Darshan Prakash +919150404758
ALL THE BEST!
Resources:
Physics:
• Question 1:
o https://www.youtube.com/watch?v=pQp6bmJPU_0
o https://www.youtube.com/watch?v=u7Rg0TcHQ4Y&pp=ygUMZWRkeSBjdXJyZW50
o https://www.youtube.com/watch?v=y-569cdIPeM&pp=ygUSZWRkeSBjdXJyZW50IGJyYWtl
• Question 3:
o https://www.youtube.com/watch?v=ozeYaikI11g&pp=ygUXdHJhbnNtaXNzaW9uIGxpbmUgb
W9kZWw%3D
o https://www.youtube.com/watch?v=kxNxBXZUR0&pp=ygUSYWNvdXN0aWMgaW1wZWRhbmNl
o https://ieeexplore.ieee.org/abstract/document/10903631/authors#authors
• Question 4:
o https://www.youtube.com/watch?v=9tlIWlGvkRchttps://www.sciencedirect.com/topics/engineer
ing/leidenfrost-effect
Mechanics and Design:
• Question 6:
o https://www.doitpoms.ac.uk/tlplib/fem/intro.php
Circuitry:
• Question 1:
o https://circuitdigest.com/electronic-circuits/cell-phone-charger-circuit-diagram
• Question 2:
o https://diygh.com/how-to-connect-ds3231-rtc-module-to-arduino-complete-guide/
• Question 3:
o https://www.youtube.com/watch?v=d3IH8zwUVYU
o https://www.youtube.com/watch?v=yvrpIYc9Ll8
• Question 4
o https://circuitdigest.com/electronic-circuits/simple-h-bridge-motor-driver-circuit-using-mosfet
o https://youtu.be/3N_4VpzmKY0?feature=shared
• Question 5
o https://www.youtube.com/watch?v=1gPQfDkX3BU
o https://www.youtube.com/watch?v=Q76dMggUH1M
Research-based Questions:
• Question 1:
o https://www.comsol.it/support/learning-center/article/Performing-Optimization-in-comsolmph55751
o https://www.mdpi.com/1996-1944/17/23/5970
• Question 2:
o https://www.researchgate.net/publication/379454029_A_Topical_Review_on_Enabling_Technol
ogies_for_the_Internet_of_Medical_Things_Sensors_Devices_Platforms_and_Applications
o https://my.eng.utah.edu/~ece1270/ECE1270_Lab1bU11.pdf
o https://www.instructables.com/EMG-Sensing-Circuit/
o https://youtube.com/playlist?list=PLwjK_iyK4LLDBB1E9MFbxGCEnmMMOAXOH&feature=
shared
o https://youtu.be/1Hd72RpMFlQ?feature=shared
o https://www.researchgate.net/publication/339832688_Classification_of_Electromyographic_Han
d_Gesture_Signals_using_Machine_Learning_Techniques
o https://www.kaggle.com/datasets/sojanprajapati/emg-signal-for-gesture-recognition/code