I'm a mechanical engineer who works where hardware meets software. At Tesla I build test systems and autonomous robots. After hours, I built and shipped HiddenCloak alone.

The through-line

  1. MeasureSensors, lasers, DAQ
  2. BreakCrash and sled tests
  3. RebuildRobots and tooling
  4. ShipHiddenCloak, on the App Store

The glowing root is my real route, Rourkela to San Jose, on true compass bearings from home. Signals travel it in the shape of a crash pulse. Each cap is a chapter; hover one.

HiddenCloak

Say what's wrong in one sentence. Get a plan for right now, soon, and later.

An iOS app I designed, built and shipped alone: the app, the API, the AI pipeline and the website. It turns a problem into small, concrete steps instead of a wall of text, then helps you keep the ones that work.

HiddenCloak action plan screen
  1. Ask

    Put it the way you'd tell a friend, in up to 500 characters. The input reminds you to leave out personal details. It's not an emergency service, and it says so.

  2. Two models, one plan

    Claude and GPT each draft the plan, then judge each other's draft, horizon by horizon. Each judge sees the other vendor's plan in the first slot, which cancels both position bias and self-preference. Agreement wins; a split is shown as an honest tie.

    Shipping in 2.0.1. Falls back to a single model if either provider is unavailable.

  3. Right now, short term, long term

    One to five steps per horizon, never padded. "Put your phone in another room 30 minutes before bed" rather than an essay on sleep hygiene. Short and long term load in behind the first horizon, so you can start reading in seconds.

  4. Keep what works

    Save the steps that fit and mark each one Worked or Not yet. Checklists live on your phone, not on a server. Optional reminders are scheduled on-device, and the lock screen never shows your problem's wording.

  5. Every step lights a star

    A checklist reads like a small night sky. Each step you finish lights a star, so progress is something you can see at a glance.

  6. See what's helped

    Insights gathers the steps that worked across your checklists, alongside general ideas that tend to help with common problems.

Try it: light a star

This is a real plan from the app. Tick off the steps you'd actually do.

“I can't fall asleep at night and wake up exhausted”

Right now
Short term
Long term
Constellation: 0 of 6 steps lit
0 of 6 worked

Built alone, end to end

Every AI call costs real money, and the app is free with no payment path. So cost, privacy and safety are design constraints, not afterthoughts.

App

Expo and React Native for iOS and Android, with Expo Router powering the web too. A liquid-glass UI kit with light, dark and auto themes.

API

Express, Prisma and Postgres on Railway. Privacy contract tests run in CI on every change to main.

AI

OpenAI and Anthropic, cross-judged. Searches are cached and cheap models are preferred, because per-request cost is a design constraint.

  • Fails closedIf a quota or moderation check can't run, the request is rejected. It doesn't log and carry on.
  • Bounded spendAI budget is capped per account, per network and globally.
  • No oraclesSearch ids are random, never derived from what you typed.
  • Private by defaultChecklists stay on the device. Analytics are anonymous counts, and you can opt out.

Autonomous
test system

At Tesla I designed and integrated a system that drives a real Tesla through the car's internal firmware: two GPS antennas and a separate base station, a Raspberry Pi running Kalman fusion, Stanley steering and PID speed control. It replaced a $450k system for about $2.5k.

Scroll, and the drawing comes apart into the four disciplines it took.

  • $450k → $2.5ksystem cost
  • 2 + 1GPS antennas on the car, plus a base station

Mechanical

I learned engineering by breaking cars properly. At Maruti Suzuki I reworked seat and body structures until they passed crash regulations. At Tesla I still draft parts in 3DX with GD&T.

  • −34%chest injury, seat structure that restrains the pelvis
  • −50%steering displacement, under the 80 mm limit
  • −80%maintenance time, flying-floor guide rollers
Simplified drawing of a guide roller on its bracket, with a diameter dimension and a perpendicularity tolerance ⊥ | 0.05 | A Ø 104
Guide roller, simplified. Not to scale.

Mechatronics

Sensors, compute and the wiring between them. My autonomous test system rides on a real Tesla: two GPS antennas on the roof, a separate base station sending corrections over radio, and a Raspberry Pi that talks to the car's internal firmware. I build test hardware myself when buying it makes no sense.

  • −90%cost, laser speed tool on a Raspberry Pi
  • +20%alignment, joystick laser track on a stepper gantry
Schematic: two GPS antennas wired to a Raspberry Pi, a separate base station sending corrections to it over radio, and the Pi sending commands over a terminated CAN bus to the car's firmware GPS 1 GPS 2 BASE STN RADIO RASPBERRY PI CAN_H CAN_L FIRMWARE 120 Ω
Test-system wiring, simplified.

Robotics & controls

Closed loops. At Tesla I designed and integrated an autonomous test system that drives a real Tesla through the car's internal firmware. Two GPS antennas and a separate base station feed a Kalman filter on a Raspberry Pi; the Stanley law steers it along the path and PID holds its speed. It replaced a $450k system.

  • $450k → $2.5ksystem cost
Block diagram: the reference path and the estimated pose meet at a summing junction and feed the Stanley controller, which steers the car through its firmware; two GPS antennas plus base-station corrections pass through a Kalman filter back to the junction path r Σ STANLEY TESLA δ GPS ×2 + BASE KALMAN
Steering loop. Speed runs its own PID loop.
Drive the Stanley simulation

Software

Tools people actually use. Python suites that check hundreds of crash channels, a model that flags bad sensors after a test, and the Raspberry Pi controller that drives the car, and HiddenCloak end to end: React Native, Express, Postgres, and two AI providers judging each other.

  • −80%troubleshooting time, shared sensor-analysis UI
  • −75%man-hours, random-forest sensor checks
  • 2.5 h → 10 minweekly channel comparison
# the steering law from the Lab simulation (illustrative, not Tesla code)
def stanley(path, pose, v, k=1.2):
    i = path.nearest(pose.front_axle)
    heading_err = wrap(path.yaw[i] - pose.yaw)
    cross_track = path.signed_dist(pose.front_axle, i)
    delta = heading_err + atan2(k * cross_track, v + 0.4)
    return clip(delta, -MAX_STEER, MAX_STEER)
Portrait of Subrat Kumar Behera

Growth map

I started in a crash lab, where the job is to break a car properly and learn exactly how it failed. Four years later, I moved to Texas for a master's degree, then to Tesla, where the test rigs started driving themselves. Scroll down and the forest floor travels the route back with you, city by city, to the roots in Rourkela.

  1. Now
    Downtown San Jose skyline at night
    San Jose at night. Photo: Ben Loomis, CC BY 2.0

    Founder and sole developer

    HiddenCloak · iOS, live on the App Store

    Designed, built and shipped a consumer AI app on my own: the mobile app, backend, AI pipeline, moderation, App Store review and website.

    Back to the bloom
  2. 2023 – now
    A Tesla Model S body on an assembly carrier inside the Fremont factory
    Tesla Fremont factory, 2013 press tour. Photo: Maurizio Pesce, CC BY 2.0

    Senior Test Engineer

    Tesla · Fremont, California

    I own sensing system performance from prototype to deployment: integration test plans, vehicle-level bring-up, and characterization across environments. I also debug where hardware and software meet.

    • $450k → $2.5kautonomous robotic test system
    • −90%cost, in-house laser speed tool
    • −80%troubleshooting time, sensor analysis suite
    All field notes 9
    • Designed and integrated an autonomous robotic system with closed-loop control using special vehicle firmware, GPS, IMU, a Kalman filter, the Stanley algorithm, PID and CAN/Etherloop communication, taking system cost from $450k to $2.5k.
    • Developed an in-house speed measurement tool for crash tests with lasers, a Raspberry Pi, Python and a modern UI, saving 90% of the cost.
    • Scripted Python to interpret and visualize IIHS test protocol data, improving repeatability and cutting manual interpretation by 50%.
    • Built sensor data analysis tools (post-test comparison and pre-test sensor checks) into a shared all-in-one UI, in a team effort with Python and git, cutting troubleshooting time by 80%.
    • Redesigned the flying-floor guide rollers in 3DX with GD&T to allow on-track assembly and disassembly, improving maintenance time by 80%.
    • Built a joystick-controlled laser track with Arduino, stepper motors and a gantry, improving test alignment by 20%.
    • Created data analysis tools that combine previous test data, video and a graphical interface (Python, VBA), cutting troubleshooting by 20%.
    • Owned sensing system performance from prototyping through deployment: integration test plans, vehicle-level bring-up, characterization, and hardware-software debugging.
    • Coordinated with project management, sensing, design and firmware teams to validate system- and vehicle-level performance.
  3. 2022 – 2023
    An instrumented crash-test dummy seated at the wheel of a test vehicle
    An instrumented crash-test dummy. Photo: Brady Holt, CC BY 3.0

    Passive Safety Testing Engineering Intern

    Tesla · Fremont, California

    I brought machine learning and automation to post-crash data, so engineers spent their hours on findings instead of spreadsheets.

    • −75%man-hours, random-forest sensor checks
    • 2.5 h → 10 minweekly channel comparison, VBA import
    All field notes 6
    • Trained a random forest on previous test data to label every crash-test sensor good or bad, with a Python GUI. It saved 75% of man-hours and closed the gap for erroneous sensors to be skipped.
    • Cut a weekly task from 2.5 hours to 10 minutes with VBA that auto-imports data to compare crash channels between test requests and the data acquisition software.
    • Improved export time for measured point features by 80% with Polyworks macros, and built Polyworks functions for easier data extraction.
    • Created a VBA Excel tool to measure post-test deformation from polyline measurements.
    • Scripted a Python GUI that pulls data from Outlook and updates JIRA tickets.
    • Updated regulation procedures and checklists so tests run more accurately and smoothly.
  4. 2021 – 2023
    The domed Academic Building at Texas A&M University
    Academic Building, Texas A&M. Photo: Donnie Ray Jones, CC BY 2.0

    MS, Mechanical Engineering

    Texas A&M University · College Station, Texas

    Controls, vehicle systems and simulation. Graduate projects modelled in Modelica and Dymola: an EV dual-battery pack, a hybrid powertrain controller and an engine-start study (see Field work).

    • 3.9 / 4.0GPA
    • Best Graduate Projectaward
  5. 2017 – 2021
    Overhead view of a frontal oblique crash test against a moving barrier
    A frontal oblique crash test. Photo: NHTSA, Public domain

    Senior Crash Testing Engineer (Deputy Manager)

    Maruti Suzuki India Ltd, R&D · Rohtak, Haryana

    Four years of crash compliance and research for India's largest carmaker, across AIS, ECE and NCAP programs. I took new and existing vehicles from design prototype release through testing within four months.

    • −34%chest injury, seat-structure research
    • 0 → 2 starsNCAP rating, two base variants
    • −50%steering displacement, under the 80 mm limit
    All field notes 6
    • Led a research project that cut chest injury by 34% by modifying the seat structure to restrain the Hybrid III 50th percentile dummy's pelvis movement, validated through sled simulations.
    • Applied a design change that cut steering displacement by 50%, below the 80 mm limit, and reduced dash panel deformation and A-A pipe bending on a challenging forward-facing wagon, with negligible cost increase.
    • Raised two base variants from 0 to 2 stars, and evaluated NCAP star ratings for upcoming models while supporting crash compliance for AIS and ECE regulations.
    • Managed product development for new and existing vehicles to completion within four months of design prototype release.
    • Integrated restraint systems through baseline model data analysis and coordination with designers and suppliers.
    • Designed a trolley transfer method that reduced worker fatigue and material transfer time by 40%, and won a best design award.
  6. 2013 – 2017
    The main building of NIT Rourkela
    NIT Rourkela main building. Photo: Sri Sankalpa Mishra, CC BY-SA 4.0

    BTech, Mechanical Engineering

    National Institute of Technology · Rourkela, Odisha

    • 8.91 / 10CGPA

Field work

The proprietary hardware stays at work. These are working sketches of the ideas behind it, so you can poke at them.

cross-track 0.00 m heading 0.0° steer 0.0°

Over the ditch, on its own

At Tesla I designed and integrated an autonomous system that drives a real Tesla over a ditch jump, holding a straight (or nearly straight) line into the ramp. It fuses GPS through a Kalman filter, steers with the Stanley law, holds speed with PID, and commands the car through its firmware over CAN and Etherloop. It replaced a $450k system for about $2.5k.

Each run here starts off the line, and Stanley pulls it in before the lip. Drag the nodes up or down to bend the approach, and change the gain to see how the controller trades responsiveness for overshoot.

δ = ψe + arctan(k·e / v)

A simulation of the published control law, not Tesla code.

Laser speed trap

Crash tests need impact speed you can trust. Two laser gates 1000 mm apart, a Raspberry Pi timing the breaks, and a Python UI give v = d / Δt for about a tenth of the commercial price.

Simulated runs at typical frontal-test speeds.

Finding the bad channel

A crash test produces hundreds of sensor channels, and one bad one can hide in the noise. A random forest trained on previous tests labels every channel good or bad right after the test, shown in a GUI, saving 75% of the man-hours.

Synthetic traces for illustration.

IIHS moderate overlap: the rear passenger's chest index

IIHS's updated moderate overlap test puts a 5th percentile female dummy in the rear seat. A belt that rides up the chest makes the sternum gauge read low, so the chest index scales the measured deflection by where the belt sat at the moment of maximum deflection. My Python scripting turns those channels into this kind of animation, so the rating can be read and checked, not just reported.

  • 0.0 mmmeasured sternum deflection
  • 0 mmdynamic belt position
  • 0%0.5% per mm above rib 3 (17 mm)
  • 0.0chest index = |deflection| / (1 − change)

Rating: …

Synthetic traces. Method and boundaries (35 / 40 / 45) from the IIHS Moderate Overlap 2.0 Rating Guidelines (Version II, June 2023). Belt positions above 110 mm are rated on belt load and position instead.

Toolkit

What I reach for, from crash labs to app stores. Hover a tool and it lights up in its own colours.

Code

  • Python
  • C / C++
  • MATLAB
  • R
  • VBA
  • TypeScript
  • Git
  • LaTeX

Robotics & embedded

  • CAN
  • Etherloop
  • ROS 2
  • Raspberry Pi
  • Arduino
  • ESP32
  • CANape
  • PCAN
  • TCP
  • Kalman · Stanley · PID

CAD & analysis

  • LS-DYNA
  • 3DX / CATIA
  • SolidWorks
  • ANSYS
  • DIAdem
  • Dymola
  • LS-PrePost
  • Polyworks

Hardware & lab

  • High-speed cameras
  • Sled machine
  • CMM
  • Metal fabrication

Learning machines

  • PyTorch
  • CNN
  • RNN
  • Data analysis
  • OpenCV

Shipping apps

  • React Native
  • Expo
  • Express
  • Prisma
  • PostgreSQL
  • Anthropic
  • OpenAI
  • Railway
  • Vercel

Languages

English, Hindi, Odia, German

Recognition

Best Employee Award · Best Graduate Project · Best design award, trolley transfer method

Off the clock

Autonomy, renewable energy, robotics, music, working out, reading

Let's build
the next one.

Happy to talk robotics, mechatronics, test systems, vehicle safety, or HiddenCloak.

Write an email