Tim's Digital Calliper Interface

🛠️ Build a USB Digital Calliper Interface with STM8S

Featuring a Fractional Inch Display App — Available on Microsoft Store

Whether you're machining, woodworking, or just love precision, digital callipers are a must-have tool. But what if you could take that measurement data and display it on your PC — with full decimal accuracy and familiar imperial fractions like “5/8″”?

In this project, I’ll show you how to build a USB interface for a digital calliper using an STM8S microcontroller, and pair it with a custom desktop app that displays live measurements in both metric and imperial formats. The app even highlights common fractional inch values — just like commercial callipers do, but with more control and clarity.

You’ll learn how to:

• Wire and decode the calliper’s data stream via UART
• Prototype the interface on a solderless breadboard
• Create a polished PCB version with help from PCBWay
• Download and use the Windows app from the Microsoft Store

Let’s make precision measurement more readable, more shareable, and more fun.

🔍 What You’ll Build

Check out my Instructable:

Tim's Digital Calliper Interface : 11 Steps (with Pictures) - Instructables

This guide walks you through interfacing a digital calliper with a PC, enabling live measurement display and fractional inch recognition. Unlike traditional vernier callipers, which require manual reading, this project uses a microcontroller to decode and transmit data from the digital calliper’s internal protocol.

You’ll start with a breadboard prototype, then move on to a professional PCB version I have had made from

Here is the link to my shared project: Tim's Digital Calliper Interface

I have put the software In Microsoft Store

Tim's Digital Calliper Interface