I want to be able to monitor my CNC mill with a cheap USB HD camera mounted on the spindle. I chose the Creative Live! Cam Chat HD (VF0700) - 1280x720p as it is very affordable and does not require drivers on any OS.
For this I could use a USB microscope, but the price is higher and they are usually too big. A normal camera can not focus closer than about 10 cm.
So I need a lense of some sort, preferably a cheap one. The cheapest one I found in my house was a loupe I use to look at SMD soldering. It is made to examine stamps, jewelry and other small things and costs just 20kr (ca. $2). Just mount it in front of the camera and suddenly the focus is down to 3-5 cm. Instant macro! :)
Step 1: Buy A Cheap Microscope or Loupe
It is just a plastic stand-alone case and a glass lens, and can be bought here: