Active developmentTested with 10 users over ~1 month
GI symptom, meal, and context logging with per-user trigger analysis.
- Next.js
- TypeScript
- Supabase (Auth · Postgres · RLS)
Terrero Labs · Biomedical engineering · software · hardware
I build software and hardware that turn physiology, behavior, and biosignals into measurable systems.
I’m Jonathan Terrero: a Software Engineer I at OmniFlex Fitness and a biomedical engineering student at Florida Gulf Coast University. Terrero Labs is the umbrella for my work as an engineer: the projects, research, and skills behind them.
Every project here states what is built, what has been measured, and what it doesn’t claim.
HeartWire · Company formation in progress
HeartWire
HeartWire is my health-tech startup, now being formally set up. It’s where the products live: MindMap, GastroGuard, SkinTrack+, HeartWire OS, and later GlucoLoop.
HeartWire · flagship product
MindMap
Longitudinal behavioral health tracking: mood, sleep, stress, symptoms, and routines as structured time-series data.
Active developmentLive web app · pre-launchAtomic daily check-in
One Postgres RPC writes a whole day, so a partial submit can’t leave a half-written record and a re-submit overwrites instead of duplicating.
Isolation in the database
Row-level security on every user table, with a SQL test suite that impersonates two users and asserts neither can see the other’s rows.
ML that is allowed to say “not enough data”
A calibrated model that abstains on thin evidence, behind a gate that blocks diagnostic phrasing. So far it is validated on synthetic data only, and the model card says so.
System architecture
Next.js 15 PWA ── check-in · journal · dashboards
│
▼
server actions ── session refresh · AES-256-GCM
│ journal encryption (server-only)
▼
Supabase ─┬─ Auth
├─ Postgres + RLS (per-user rows)
└─ upsert_mindmap_entry(jsonb)
▲
│ reads entries · writes predictions
Python ML (offline) ── rule baseline · calibrated
model · abstains · output gate- Active developmentCatalog integrity audit pending
HeartWire’s study app: a structured catalog of courses, resources, and levelled project ideas across engineering domains.
- Next.js
- TypeScript
- Prisma
- PrototypeUnder reconstruction · links withheld until rebuilt
Structured longitudinal documentation of chronic skin conditions: photos time-indexed against symptoms, medication, and environment.
- Next.js
- TypeScript
- PWA
- ConceptPlanned — nothing built yet
A planned HeartWire product: a faster feedback layer on top of continuous glucose monitor data.
Hardware, devices, models
Engineering
Physical builds and computational models: embedded firmware, mechanical design, and physics you can re-run.
- CompletedCourse project · functional demo
Arduino firmware for a 4-servo arm: colour sorting, handing an object to the arm, a proximity safety stop, and a closed-form inverse-kinematics solver.
- Arduino Uno (C/C++)
- Servo control
- Colour sensing (LDR + RGB LED)
- PrototypeFEA below safety target · parametric rebuild done · print pending
A 3D-printable, modular knee brace: snap-fit hinges, swappable connectors, and frames rebuilt as a parametric CAD model.
- SolidWorks
- SolidWorks Simulation (static FEA)
- Fusion 360 (parametric)
- CompletedPhysiology for Engineers I & II · live on GitHub Pages
Seven physiology systems modelled as differential equations in MATLAB/Simulink, then rebuilt as interactive browser simulations — from cardiac pressure–volume loops to Hodgkin–Huxley action potentials.
- MATLAB
- Simulink
- JavaScript
- Active developmentLive on GitHub Pages
Interactive, parameter-driven models for five biomedical engineering courses — the governing equation and a live plot on the same page.
- HTML
- JavaScript
- Chart.js
Case studies
Research
Device teardowns, stakeholder interviews, and literature review — the analysis side of the engineering work.
- ResearchCase study
Reverse-engineering a Class II reverse shoulder arthroplasty system end to end.
- Biomechanics
- Materials (Ti-6Al-4V, porous titanium, crosslinked UHMWPE)
- FDA 510(k)
- Research12 interviews · 8 physicians
Interviews with 12 healthcare professionals on where engineering fails clinicians, and what they actually need.
- Qualitative research
- Stakeholder interviews
- Systems engineering
- ResearchSystematic review · 11 studies
A PROSPERO-registered systematic review of material degradation in cobalt-chromium dental prostheses.
- Systematic review
- PRISMA 2020
- PubMed / Scopus / Web of Science
How this portfolio is written
Evidence over adjectives
Each project follows a ten-part template — problem, requirements, architecture, decisions, scope, implementation, verification, failures, limitations, and links — and every claim is tagged before it’s published.
Verified
Traceable to code, a deployed artifact, or a recorded measurement. This is the only kind of claim on project pages.
Pending
Marked in amber on each page, with the planned test. Not filled with estimates — a blank is recoverable; a number I can’t reproduce isn’t.
Not claimed
Every health product states what it isn’t: not a medical device, no FDA evaluation, correlational output only.
Experience
Production software
Software Engineer I · OmniFlex Fitness (remote)
May 2026 – present
- Built a batched Firestore write pipeline and typed data-access layer that cut Firestore reads/writes per session by 10%.
- Removed a class of subscription-leak concurrency bugs with OnPush change detection and takeUntilDestroyed subscription hygiene.
- Ship features across an Angular task platform and a real-time multiplayer trivia app (Firebase, Flutter) on a weekly release cadence.
B.S. Biomedical Engineering, Florida Gulf Coast University · minors in Physics and Computer Science
Expected May 2027
Coursework
Relevant courses, and what they produced
Physiology for Engineers I & II
ODE models of cardiovascular, metabolic, cellular, and neural physiology in MATLAB/Simulink
Quantitative Physiology Models →Biofluid MechanicsBME 3261C
Blood rheology, hydrostatics, stenosis flow, and a CPAP design-challenge simulation
BME Visualizations →Biomechanics
Sagittal-plane knee equilibrium and patellar-tendon force model
BME Visualizations →Bioperformance of Materials
Graphene-oxide fibroblast-recovery study design and degradation models
BME Visualizations →Medical Instrument Architecture
Medical-device signal chain from measurand to display, with patient isolation
BME Visualizations →Biomedical Signal Models
Electrode loading, sensor linearity, CMRR, noise, and filter design
BME Visualizations →Intro to Mechatronic Design
Arduino firmware: FSM control, sensing, and inverse kinematics for a robotic arm
Robotic Pick-and-Place Arm →Design for ManufacturingEGN 3433C
Where the modular knee brace started: SolidWorks design, manufacturing choices, and static FEA
Modular Knee Brace →Circuits
Circuit analysis — the basis for the instrumentation signal-chain models
Signals & Systems
LTI systems, transforms, and filtering — the basis for the filter-bank and signal models
Capabilities
What I can build, and where it shows
Core Engineering
Python · C/C++ · MATLAB · TypeScript
Evidence: BME Visualizations, Co–Cr Dental Prosthesis Degradation Review, Engineering the Healthcare Supply Chain, Modular Knee Brace, Quantitative Physiology Models, Robotic Pick-and-Place Arm, Stryker ReUnion RSA Teardown
Full-Stack & Data Systems
Next.js / React / Angular · Supabase (Auth, Postgres, RLS) · Firebase / Firestore · PostgreSQL / SQL · API Design (REST, FastAPI, Django)
Evidence: GastroGuard, HeartWire OS, MindMap
Data & Signal Analysis
Time-series feature engineering (lags, rolling windows) · Correlation analysis with explicit limitations · Calibration and abstention for predictions · Data visualization (Recharts, Chart.js, Matplotlib)
Evidence: BME Visualizations, Co–Cr Dental Prosthesis Degradation Review, GastroGuard, MindMap, Quantitative Physiology Models, SkinTrack+
Biomedical + Embedded Systems
Arduino / microcontroller programming · Sensor integration (FSR, ultrasonic, photoresistor colour sensing) · PCB design + breadboarding · SolidWorks / Fusion 360 CAD + FDM printing · Biomechanics and orthosis design
Evidence: BME Visualizations, Modular Knee Brace, Quantitative Physiology Models, Robotic Pick-and-Place Arm, SkinTrack+, Stryker ReUnion RSA Teardown
AI + Automation Systems
Claude Code Skills · Claude API (Managed Agents) · OpenAI API · scikit-learn (calibrated logistic regression) · GitHub Actions
Tools & Workflow
Git / GitHub · Linux · Vercel · Cursor · Docker · Obsidian · Structured project systems
Evidence: Engineering the Healthcare Supply Chain, HeartWire OS, JonnyJr