Modular Conductivity Tester based on Eddy current

About the project

I need a compact, modular eddy-current device built from the ground up to verify the purity of non-ferrous metals during material research and development. Because the unit will often be carried to mines, scrapyards, and temporary field labs, I’m prioritising a rugged, weather-resistant enclosure, battery operation for a full working day, and quick-swap probes so I can tailor frequency and coil geometry to different sample shapes. Core expectations • A handheld main unit that houses the signal generator, receiver, display, data-logging memory and rechargeable power pack. • Interchangeable probe modules covering the typical kilohertz-to-megahertz range used for non-ferrous purity checks, each probe auto-calibrating on connection. • On-board firmware that shows impedance plane plots and numeric purity indices in real time, with simple zero, lift-off and reference calibration routines. • A desktop companion app (Windows or cross-platform) for deeper analysis and CSV export via USB-C or Bluetooth LE. • Complete build package: schematics, PCB files, firmware source, 3D CAD for the housing, and a short user guide so my lab team can reproduce and service the unit. Acceptance criteria 1. The prototype must detect at least a 2 % change in conductivity between known aluminium, copper, silver gold and gold alloys reference standards in an outdoor environment. 2. Logged data must match readings displayed on the handset (±1 % deviation) when imported into the desktop app. 3. All documentation supplied in editable formats. Familiarity with eddy-current instrumentation, analogue front-end design, microcontrollers (e.g. STM32, ESP32), and enclosure prototyping will be key to delivering a field-ready tester that I can take straight into use.

Skills required