Filament quality measurement

A local company ran a machine that extruded filament for 3D printers, and they needed two things they didn't have: a way to know how far each spool drifted from spec, and a way to trace any spool back to the run that produced it. I built the system that did both, end to end — from the sensor on the line down to the database.

The measurements

A prebuilt measuring unit sat on the production line and read the filament as it was wound. I wired it to a Raspberry Pi over a serial interface, and the Pi streamed every reading into a MySQL server — so deviations were captured continuously instead of spot-checked by hand once a shift.

Spool tracking

The spooling itself ran on the company's own custom mechanism, so I left that alone and tapped into it: a pressure switch that triggered the moment a spool filled up. That signal told the Pi to close the spool out, assign it a serial number, and print a label on a connected printer. Every finished spool came off the line already tagged and already in the database.

It was some of my earliest hands-on work tying hardware straight to software — a sensor, a microcontroller, a database, and a printer all made to agree with each other. That thread, making the physical and digital layers line up, kept resurfacing later: in the NFC payment tokens at NFCtron, and in my own hardware side-projects since.