Dec 2025
PureMetric
PureMetric is a sensor-based system for monitoring beverage freshness after a drink has been opened. It tracks pH value, temperature, total dissolved solids, and turbidity inside the container, streams those readings into a dashboard, and estimates how long the drink is likely to stay drinkable.
Sensing Motivation
Inspired by the gap between how freshness is usually judged and how liquids actually change over time, PureMetric treats beverage spoilage as a sensing problem. Rather than relying on appearance or smell alone, it samples the liquid directly and turns subtle change into a clearer reading of freshness.
System Flow
The project was structured as a compact sensor-based system rather than a standalone container. Four measurements are sampled once per second, passed through the microcontroller, and routed either to USB serial during bench testing or through WiFi and MQTT into the Node.js backend. From there, the data moves into InfluxDB, filtering, and forecasting before reaching the dashboard.
Sensing Prototype
Early prototype testing focused on whether the four signals could describe freshness together. pH value tracks acidity, temperature shapes spoilage speed, total dissolved solids reflects dissolved content, and turbidity captures cloudiness in the liquid.
Serial test. Before the enclosure was finalized, the sensing stack was read through the serial monitor to check whether the full sensing pipeline stayed stable from sensor to computer.
Liquid test. The sensor set was placed directly in coconut water to observe how live readings behaved inside a real drink rather than a controlled setup.
Interface Design
The dashboard works as the interpretive layer of the system. Live cards keep each signal legible at a glance, historical views make slower shifts easier to notice, and the forecast layer translates those sensor trends into an estimated drinkable window.
Form Exploration
Once the sensing workflow was working, the project shifted from exposed wiring to product form. The enclosure needed to hold liquid, protect electronics, and keep the sensing process visible without carrying the look of lab equipment.
Sketches
Product
Packaging Design
The CAD phase focused on packaging the sensing stack into a compact volume. Probe depth, board placement, reservoir geometry, and the split between wet and dry zones all had to be resolved together before fabrication.
Exploded View
Internal Layout
Integrated System
Key status stays visible on the container during everyday use, while the app supports remote monitoring with the full sensor stream. This makes it easier to check live readings, review histories, and follow longer changes across pH, temperature, total dissolved solids, and turbidity.
