This whole project started with a phone call from a friend who designs custom industrial machines:

- Hey Dorian, I need to measure how the electrical resistance of automotive connectors changes as they get mated and unmated thousands of times. Is that something easy to do?

- Well… that depends on what resistance values we’re talking about.

- Around 60 micro-ohms.

- And what’s your budget?

- Under €1000 ... for the whole electronics part of the test bench... and everything has to fit in something the size of a shoebox.

At that point, I couldn’t help but laugh.

When I started looking into it, I realized I couldn’t find any instrument that could:

• Resolve a few micro-ohms reliably,
• Connect to a PC over USB,
• Be compact and robust enough for industrial use,
• And still cost under €500 (most commercial units are well above €1000).

The closest solution I found was to cobble something together using a programmable lab power supply and a bench multimeter in a 4-wire setup, all controlled by a PC.

With decent Siglent gear that would have cost around:

• SDM3045X 4½-digit multimeter – €369 (excl. VAT)
• SPD1168X programmable power supply – €229 (excl. VAT)

So about €600 per measurement channel, and that’s just for the instruments — not exactly compact or budget-friendly.

And that’s when I decided to build my own tool.

In the next logs, I’ll dive into why measuring such low resistances is tricky, and show the open‑source design that kick‑started this project.