Advanced Humidity Monitoring System
Invisense measures moisture inside building structures without opening them up. The sensor is a passive thin-film inlay cast into the structure; a handheld reader takes the measurement straight through the wall. I wrote the firmware and the measurement algorithm, built the app, and took the radio through CE certification.
The sensor is a printed inlay (a spiral antenna coil and a pair of metallised pads on a flexible film) sealed into the structure with no power source and no radio of its own. All the electronics live in the handheld reader, which is held against the wall and takes the measurement through the material in between. Nothing has to be opened up to get a reading, and nothing buried in the building can go flat.
A reading only happens where the reader can reach, so this is a measurement taken on site, with the unit held against the wall. Once the structure is closed, the inlay is invisible. Finding one is a drawing exercise: the sensor positions are specified in the building plans, and the reader goes where the plans say.
A cross-platform React Native application for Android and iOS handling monitoring and data visualisation, developed in step with the measurement algorithm itself, because what the algorithm can honestly report and what the app should show a builder standing in a basement are the same design question.
The BLE design was chip-down rather than a pre-certified module, so there was no module certification to inherit and the product needed a full radio sweep: an anechoic chamber, a biconical antenna and a turntable, not a paperwork exercise. I led it, as liaison and on-site representative throughout. Being in the room is most of the job: the lab finds something, and you change the firmware that afternoon.
Assembly, firmware flashing and QA of 50+ units, done hands-on rather than handed to someone else, plus hardware design advisory and on-site troubleshooting when the boards did not behave the way the schematic promised.
Firmware & Application Developer
Embedded C / FreeRTOS / React Native / Hardware QA / CE Certification / IoT
50+ stations deliveredPrincipal Engineer
Real-time scoring system for GYMRACE fitness competitions
Raspberry Pi / Node.js / TypeScript / React +5
BLE and storage redesignSystem Developer & Hardware Engineer
Wearable ECG Monitor Hardware Redesign
Hardware Design / PCB Design / Embedded C / BLE +2
1000+ units shippedFounder & Technical Lead
IoT Health Tracker for Children
Hardware Design / Embedded C / FreeRTOS / BLE +4
Next step
Send me a short description of the problem and I'll tell you whether I'm the right fit, what it would cost, and how long it would take. No pitch deck.
