Is your ESD wrist strap really protecting you? This simple ESP32-S3-based tester quickly checks the resistance of the strap-to-wearer path and instantly reports whether it's safe to use.

Why Test the Strap?

An electrostatic-discharge (ESD) wrist strap is one of those safety devices that everyone trusts and almost nobody checks. The strap is meant to bleed static charge from the wearer to ground through a built-in current-limiting resistor, usually around 1 MΩ, so that a person handling sensitive components stays at the same potential as the bench. This only works while the whole path stays intact. A cracked resistor, a corroded snap, a dried-out conductive cuff, or a strap that simply is not making good skin contact can all leave the wearer isolated, with no outward sign that anything is wrong. This project is a small tester that checks that path and shows the user, at a glance, whether the strap is doing its job.

The accepted safe window for a wrist-strap system is wide but fi...