What it is
Plastics look alike. A PET bottle and a PVC offcut can sink in water the same way. But heat them and PVC gives off hydrogen chloride. So before anything goes into a heated machine here, we need to know what it is.
Le Nez (“the nose”) is our fork of the open-source Plastic Scanner. It shines a set of near-infrared LEDs — light just beyond the red end of what our eyes can see — on a sample, one colour at a time, and measures what bounces back. Each plastic reflects a slightly different pattern: a fingerprint. A small classifier reads the fingerprint and names the plastic.
We are adding other cheap senses to the same tool: a float test, a camera with UV light, a static-charge probe and a halogen check. No single sense is reliable on its own. Together they should be.
Why it matters
- It is the safety gate. Nothing unidentified gets heated.
- It sorts bottle caps, which rarely carry a resin code.
- It builds a dataset. Every scan is labelled data from real local waste. Very few people publish that.
Honest limits
It cannot read black plastic: carbon black swallows the light. Thin film and dirty samples read badly. The upstream project has been quiet since 2024 and calls its board an early prototype, so we expect to debug it ourselves. One of the original LEDs is no longer made.
Where it stands
Design, parts list and New Zealand sourcing are written. The parts have not been ordered yet. When they arrive: build, calibrate on a labelled set (including a real piece of PVC pipe), and publish the accuracy, failures included.
Done when: PVC is caught every time in a blind test of 20 samples.
Les plans sont gratuits — the plans are free.
