AntarSpand HealthTech · Signal Processing · AI/ML
BCG Channel 1 · PVDF · 250 Hz

The body speaks in waves.

Engineering the next generation of contactless health monitoring.

Deep dives into the engineering behind wearable health tech — BCG signal processing, sleep-stage AI, sensor design, and the systems that make non-invasive monitoring possible.

What your body is telling you

19.8M

Heart disease is #1 cause of death globally

19.8 million people die from cardiovascular conditions annually. Most of these conditions are detectable early — the challenge is that the warning signals appear long before any symptoms do.

WHO / Global Burden of Disease 2022
10+ years

Heart disease builds silently — for over a decade

By the time most people receive a diagnosis, the condition has been developing silently for years. Early detection — not just treatment — is what changes outcomes.

American Heart Association · ESC Guidelines 2023
1 Billion

1 billion people have sleep apnea and don't know it

Sleep apnea causes brief pauses in breathing during sleep, repeatedly straining your heart through the night. A simple sensor under your mattress can detect it passively — no clinic visit needed.

Lancet Respiratory Medicine 2019
Days early

Your heartbeat changes days before you feel sick

Heart rate variability (HRV) — the slight variation between each heartbeat — reflects how well your body is coping. It drops days before illness, burnout, or a cardiac event, giving you an early window to act.

Frontiers in Neuroscience 2020
< 5%

Almost nobody monitors their sleep health

Yet sleep is when your body repairs itself and your heart works hardest. A single night of data can reveal patterns that a routine checkup would completely miss.

Sleep Advisor Global Survey 2024
~$0

Nightly health monitoring now costs nothing extra

A hospital sleep study costs $3,000–$5,000 and happens once. A contactless sensor under your mattress tracks your heart rate, breathing, and sleep stages every night — automatically, with no wires or effort.

AntarSpand · Clinical cost comparison 2024

Latest writing

BCG · ECG · Signal Processing

ECG and BCG: Reading Your Heart's Electrical and Mechanical Signatures

Every heartbeat leaves two distinct traces — an electrical fingerprint in the ECG and a mechanical recoil signature in the BCG. Understanding both is the foundation of contactless cardiac monitoring.

Chinmay Bhagat 10 min read
AI / ML

Knowledge distillation: teaching a BCG model with ECG labels

When your teacher model is 85% accurate and your student input is noisier, you use that gap intentionally.

8 min read
Sensor Hardware

PVDF vs capacitive: which sensor survives a restless sleeper?

Two sensor modalities, one hostile environment. After six months of field testing, here is what actually breaks.

5 min read
HealthTech

The engineering stack behind contactless vitals: from PVDF film to sleep stage

Sensor physics, ADC design, embedded firmware, cloud DSP, and the ML inference layer that ties it together.

14 min read
HealthTech

BLE for overnight ECG: what the spec sheets don't tell you

Bluetooth Low Energy looks ideal for overnight biosignal recording. The spec sheet omits the parts that will break your study.

7 min read
Deep Learning

Transformers for biosignals: what the hype gets right (and wrong)

Attention mechanisms are genuinely useful for long-context physiological signals. The implementation details are where most papers quietly fail.

11 min read
BCG / HRV

Building a Signal Quality Index from scratch

An SQI is the immune system of your BCG pipeline. Here is how to build one that actually rejects bad data without being paranoid.

9 min read
BCG / HRV

Snoring detection from BCG: separating breath from ballistic noise

Snoring produces a characteristic vibration signature in BCG. Isolating it from cardiac and respiratory signals requires understanding all three simultaneously.

6 min read

The person behind the signal

  1. ECG–BCG Synchronization Pipeline

    Full-stack system aligning Polar H10 ECG with BCG (PVDF Sensor). R peaks detected via SciPy's signal module; BCG J peaks extracted and filtered using z-score based thresholding to retain only high-confidence peaks. Cross-correlation between R and J peaks computes per-beat alignment. R-to-J peak matching with ±50ms delay handling and drift logging.

    • Python
    • NumPy/SciPy
    • asyncio/BLE
    • Polar H10
    • PVDF
  2. Contactless Vitals Stack

    End-to-end pipeline extracting heart rate and respiratory rate from raw PVDF BCG signals — no contact, no wearable. Bandpass filtering, peak detection, and RR interval analysis to deliver continuous vitals from an under-mattress sensor.

    • Python
    • SciPy
    • PVDF
    • BCG
  3. Snoring Detection via BCG

    Vibration-based snoring classifier using under-mattress PVDF sensor — no microphone required. Frequency-domain analysis of BCG signal to distinguish snoring events from movement artifacts and normal breathing patterns.

    • Python
    • SciPy
    • scikit-learn
    • PVDF
  4. Multi-Sensor Signal Processing

    Evaluated and extracted meaningful insights from diverse sensor modalities — contactless vitals (HR, respiration) from PVDF, bed occupancy and posture detection from custom capacitive sensors. Demonstrates the ability to adapt signal processing and data science techniques to any sensor to unlock actionable health insights.

    • PVDF
    • Capacitive Sensors
    • Signal Processing
    • Python
    • scikit-learn