Microscopic

My eyes aren't so good anymore, so I have a head mounted magnifier that I got from Lee Valley some years ago. But for the current work I'm doing, I needed to get even more magnification. It turned out to be surprisingly easy.

I remember reading that by reversing the lens in a webcam, you can make a USB microscope. I had an old Logitech webcam lying around since my new laptop has an integrated one, and there's instructions on Instructables.

It took about 10 minutes before I was seeing stuff in the Quick View panel with the lens bodged on backwards with blue tape.

The trouble is, the position of the camera and specimen need to be micro-adjusted and then held in one position for long periods of time... hey wait a minute I have a X,Y,Z stage with just those properties.

So clamping the "microscope" onto the print head and running PrintRun to position it turns out to be a very good control system to look at your samples (if you turn the printhead fan off). It also shows some other interesting info.

For example, I now realize how much backlash I've got in my axes, because the image from the microscope is exquisitely sensitive to even the smallest motion. So how many times do you need to touch the 0.1mm step button in one direction to see motion after taking a 1mm step in the other direction. This I'll need to experiment with, so more on that later.

But I did find out what I wanted to find out - the two traces I was laying down were not touching. I'm guessing at the numbers here, but I think the magnification is about 300 times in the picture below, and the PLA trace running diagonally up from left to right (it looks like icing that's been scraped with a spatula) is about 0.35mm wide and is separated from the next trace in the lower right hand corner by 0.13mm.