Turning a Bluetooth Caliper into a FreeCAD Input Device
When I spotted a used Sylvac S_Cal EVO caliper on eBay for €90, I jumped on it. Swiss-made precision instruments don’t usually fall into hobby budgets, but here was my chance: a Bluetooth-enabled digital caliper that normally costs 3-4× as much. I thought I was buying a better measuring tool. I didn’t realize I was buying a new FreeCAD input device.
I’ve developed a Python library, sylvac-measure, that can read measurements from the S_Cal EVO over Bluetooth.
Using that library, I created a FreeCAD addon called InstrumentInput which allows you to click on any dimension field in FreeCAD, take a measurement with the caliper, and have the value appear instantly in the field with proper units.
This eliminates the need for manual transcription, reduces errors, and creates a seamless workflow between physical measurement and digital modeling.
Take a look at my video below to see it in action.