Pulse

I built a privacy-first ESP32 sensing prototype with structured observation windows and stable embedded test workflows.

Role: Embedded systems engineer
Year: 2026
Discipline: Firmware, wireless sensing

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01 Overview

What I built

I used an ESP32 to prototype privacy-preserving Wi-Fi, BLE, and local acoustic sensing in Pulse.

The system

I structured Pulse around local-only observation windows.

I designed it to sense events without retaining persistent raw personal identifiers.

I also built a Pulse-Platform Phase 0 slice and backend claim-diagnostics support for public venue exploration. The public surface stays separated from private data and uses clearly labeled simulated data, not a live venue feed.

I keep the repository private, and the current design keeps privacy at the collection boundary.

CAD render of the Pulse black assembled enclosure with woven grille and stand — Assembled black Pulse prototype with its acoustic weave, electronics enclosure, and stand.

02 Challenge

The design constraint

I wanted useful multi-sensor observation without collecting more user-relevant data than necessary.

What I had to protect

I needed useful Wi-Fi and BLE observability without retaining raw identifiers or collecting unnecessary data.

I needed acoustic observation to stay local, with quality-aware windows and little downstream data risk.

I also needed to validate window generation, multi-window stability, and sensor state over time.

03 Process

How I built and tested it

I implemented end-to-end sensor loops and ran controlled tests and soak checks.

What I implemented

I implemented Wi-Fi and BLE polling plus PDM-based sound windows with relative RMS/peak and status and quality outputs.

I rotate and scope identifiers so temporary values are short-lived and hashed before window-level use.

I separated Wi-Fi and BLE domains and added schema checks for repeatable validation.

How I validated it

I ran controlled RF scenarios with 1, 5, and 20 identity cases, along with reset and watchdog stability checks.

I ran soak tests and monitored hardware status on the active platform.

The reviewed firmware lineage includes optional STCC4 climate sensing and OLED health/status paths. Current-head hardware acceptance and physical qualification remain open.

The product path now includes a custom PCB with a breakaway module and a new enclosure. Firmware runs on a prototype matching the PCB design; board manufacturing review is underway.

CAD render of the Pulse black prototype exploded view showing enclosure and internal parts — Exploded Pulse enclosure and internal sensing hardware.

CAD render of the Pulse prototype PCB and embedded sensing electronics close-up — Close-up of the embedded board and sensing components inside Pulse.

04 Outcome

Current state

I have firmware and a user-facing web interface built; the prototype is nearing completion while the PCB/enclosure package remains in manufacturer review and preproduction.

Where it stands

I have firmware and a user-facing web interface built, with a local observation pipeline, backend/platform software, and a simulated venue demo. The prototype is nearing completion while the PCB/enclosure package remains in manufacturer review and preproduction.

I kept privacy constraints in the collection path, added repeatable tests, and kept occupancy estimation in development while live sensor-to-dashboard integration, validated accuracy, and production deployment remain open.

Repository: Private repository
Status: Firmware ready · prototype nearing completion
Hardware: PCB + enclosure in manufacturer review / preproduction
Backend: Implemented platform and diagnostics

Modeled acoustic weave and same-material embossed Pulse logo.