The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Day: February 20, 2020

  • MPCNC: bCNC Probe Camera Refresh

    For the usual inscrutable reasons, updating bCNC killed the USB camera on the MPCNC, although it still worked fine with VLC. Rather than argue with it, I popped a more recent camera from the heap and stuck it onto the MPCNC central assembly:

    bCNC - USB probe camera - attachment
    bCNC – USB probe camera – attachment

    This one has a nice rectangular case, although the surface might be horrible silicone that turns to snot after a few years. The fancy silver snout rotates to focus the lens from a few millimeters to infinity … and beyond!

    If you think it looks a bit off-kilter, you’re absolutely right:

    bCNC - USB probe camera - off-axis alignment
    bCNC – USB probe camera – off-axis alignment

    The lens image reflected in a mirror on the platform shows the optical axis has nothing whatsoever to do with the camera case or lens snout:

    bCNC - USB probe camera - off-axis reflection
    bCNC – USB probe camera – off-axis reflection

    Remember, the mirror reflects the lens image back to itself only when the optical axis is perpendicular to the mirror. With the mirror flat on the platform, the lens must be directly above it.

    Because the MPCNC camera rides at a constant height over the platform, the actual focus & scale depends on the material thickness, but this should be typical:

    bCNC - USB Probe Camera - scale - screenshot
    bCNC – USB Probe Camera – scale – screenshot

    It set up a Tek Circuit Computer test deck within 0.2 mm and the other two within 0.1 mm, so it’s close enough.

    The image looks a whole lot better: cheap USB cameras just keep improving …