Hey all - this is a project I started working in early March, and ended up coming together quicker than I expected. There's been a general lack of force curve data since HaaTa largely stopped publishing curves on Plotly (due to issues with the Plotly website apparently). After xyz posted some
photos of a prototype meter on the Keyboard Atelier Discord using a stepper motor and a load cell rather than the expensive test stand and force gauge that Haata used, I was inspired to do something similar. It's still a work-in-progress, and I still need to do a thorough calibration of it, but I've been able to get a couple of curves out of it.
All the files (CAD, PCB, and firmware) are available on Github here, and I go into a more detailed writeup there.
https://github.com/bluepylons/Open-Switch-Curve-MeterThis was designed specifically for MX switches to simplify the design and make everything cheaper and more compact, and since most of the switches I am curious about (as well as almost all new switches released today) use the MX form factor. In theory it could be adapted to test say, Alps or other discrete switches (it would need a different plate and switch holder). This is not as versatile as force-curve testers like Haata's that use a test stand, and can't test arbitrary keyboards like that one, but it's much cheaper to build (I spent about $200 building this, and in theory this is buildable for ~$100 if one foregoes the custom PCB and order the parts from China.)