Ultrasonic Alignment tool for Bed Leveling+zeroing of stage + Filament monitor

[ShadowX]

My effector is round there is no way to attach to it in the current configuration. Worse case, I can custom design a holder for it.

I have a CNC milling machine. Even with that machine, I don't see how the device would be useful. Some of my tools are over 3 inches from tip of the Tormach holder to the spindle. Any slight angle in relation to the tool bit would throw off the measurement. I use a height gauge to measure the tool tip to the Tormach reference plane on a surface plate and use a spring loaded dial indicator to measure from my reference height to the top surface of the raw stock. I am able to maintain .001 inch accuracy using that method. In cases like a drill bit or an engraving bit, the tip is so small that I doubt the ultrasonic sensor can detect the tip distance and get a reliable distance measurement. I really have a hard time trying to think of a useful use case where this device is superior to other methods either in accuracy, cost, or time savings.

In terms of monitoring the spindle, that is what a tachometer is for. You can use reflective tape or other methods. I guess you can interface the device with Mach3 and get feedback, but most people don't leave a machine running at full cutting speed without being nearby. Its dangerous and negligent to not monitor or be near it while its running unless the mill is fully enclosed.

the device uses an adhesize magnetic strip that attaches to the print head. The measurer then magnetically attaches to the strip.
ie: no ferrous parts are needed. I've gota roll of magnetic sticky tape in my workshop, useful stuff.

So if the device doesn't need to line up with the printhead - how can you know how far the printhead is from the bed.
I know I'm labouring this point - but I just don't see how it works.