VF Nutrient Scanner
Portable Fluorescence Spectrometer for Food Quality
Overview
Designed and built a portable fluorescence spectrometer for The Mushroom Initiative (菇菌圓) — a Hong Kong NGO — to instantly measure antioxidant and chlorophyll content in fresh vegetables and fruits. The device gives consumers an objective indicator of food nutrient density at point-of-purchase, addressing the declining nutritional value in industrial agriculture. Funded by the Hong Kong Innovation and Technology Fund for Better Living (FBL).
Architecture
Architecture: ESP32-based fluorescence spectrometer with UV excitation source and photodiode array detector. Firmware in C++ (ESP-IDF) controls UV LED activation, captures emission spectra (polyphenol fluorescence at ~400nm, chlorophyll at ~680-735nm), and computes antioxidant/chlorophyll indices via spectral analysis. BLE pairs with a companion mobile app for real-time display. Cloud database aggregates user scans for statistical comparison and nutrient density ratings.
Key Technical Decisions
- 01.Designed a portable fluorescence spectrometer using UV excitation to measure polyphenol (antioxidant) and chlorophyll emission spectra in fresh produce.
- 02.ESP32 firmware in C++ (ESP-IDF) controlling UV LED activation, photodiode array sampling, and real-time spectral analysis on embedded hardware.
- 03.BLE integration with a companion mobile app delivering instant antioxidant and chlorophyll readings to consumers at point-of-purchase.
- 04.Cloud database architecture aggregating crowd-sourced scan data for statistical nutrient density comparison across produce samples.
- 05.Project funded by the Hong Kong Innovation and Technology Fund for Better Living (FBL), validating the device's public health impact.
Outcome
Delivered a field-deployable spectrometer that gives consumers instant, science-backed nutrient density readings — bridging embedded hardware engineering with public health impact for a Hong Kong NGO.