heres a medium-resolution usb microsope i made for under $100 in parts (if you bought them new), had most of this around already and made a new tool :)
1 radioshack pocket scope
1 white led
1 logitech notebook pro quickcam (zeiss lens)
30 awg wire
heatshrink or black tape
hotglue gun (or whatever appropriate glue your prefer)
(cheap plug) http://www.makenyc.org/
Step 1: Modify the Microscope
use your heatshink/tape here to insulate the leads.
test your light with a battery and make note of which lead is the anode/cathode.
on the camera board there is a small (freaking bright) orange led, *carefully* remove it, and wire the leads from our white LED in its place, with this camera the LED is under software control, usb provides all the power. make sure these leads have plenty of slack.
be generous with the hot glue to help act as strain relief on the wires; also be careful positioning the white led so that it points generally where the camera lens points
Step 2: Remove Plastic Packaging From the Camera
but from what i remember there is a metal shield with the logitech logo on it, if you pry that up and away from the glue, theres a single screw holding the entire case together..
Step 3: Assembly!
next remove the little rubber bit from the microscope eyepiece, notice that that inside edge of the eye piece has a graduated cone shape, this will help the camera fit square on, it might even help to do this with the camera connected so you get the camera mounted to the microscope nice and square.
a nice ring of hot glue around the remaining microscope will help mount the lens of the camera to the microscope eyepiece without getting any glue anywhere near the lenses.
Step 4: Make a Base
the idea here is that the magnet will easily slide but otherwise wont move; which is an otherwise frustrating problem with tiny tiny things..
Step 5: Take Some Pics!
one really neat thing i had around was a piece of core memory from an old CDC-6600 machine (classic machine nuts can begin going crazy now)
so below you can see a broad picture of the board, and the other picture which is a close up of the torriod and wire mesh that make up the memory cells
since the camera is a 2 megapixel camera its got pretty good resolution, the software logitech makes for it seems like it was made for the job. and the zeis lens has an electromechanical focus that seems to adjust to the bizarre focal length we have here.