Input FreeCAD Dimensions Directly From Bluetooth Calipers

Every time I create a model of a functional part in CAD, I sit there taking measurements with my calipers and entering them as dimensions. It would be much more convenient if the calipers could beam measurements directly into the CAD software to save me time and the potential ramifications of typos. Now that is possible thanks to this FreeCAD plugin called InstrumentInput that works with Sylvac S_Cal EVO Bluetooth-enabled digital calipers.

I have always had respect for FreeCAD, simply because it is open source in a world full of very expensive professional CAD software. But I’ve been using that professional CAD software for nearly 20 years and I have to admit that I’ve felt like FreeCAD was clunky at best. However, it has improved a lot in recent years and is now genuinely practical — even if it isn’t yet on par with professional software.

More importantly, being open source and community-driven makes FreeCAD perfect for this application. Steffen Vogel was able to write a Python library and use that to develop his own plugin for FreeCAD, which is something that would have been difficult or impossible to do with most popular professional CAD software.

That plugin has a simple job: communicate with Sylvac S-Cal EVO calipers over Bluetooth and retrieve dimensions.

The InstrumentInput plugin is available through the FreeCAD Addon Manager, so installation is easy. Once installed, you just need to connect the calipers to your computer through Bluetooth. After you do, any selected dimension will automatically update to mirror the caliper measurements.

It is really cool to see the model update in CAD in real-time as the caliper jaws open and close. And it makes dimension entry fast and accurate.

If you use FreeCAD and own compatible Sylvac calipers (or are willing to purchase them), the InstrumentInput plugin is a no-brainer.