What I needed was a stand which would do three things:
1. Hold the microscope so that it is perpendicular to the table.
2. Hold the microscope rigidly.
3. Provide a focusing knob, so that the focus can be adjusted accurately without disturbing the specimen.
I wanted a small rack-and-pinion mechanism for the focusing. I considered several options, including re-purposing parts from an old photo enlarger. In the end, it was the same vendors on eBay from whom I bought the microscope that provided the missing parts. I got a macro focusing rail that was very inexpensive and fit the bill perfectly.
With the microscope attached to the focusing rail, all I needed was a rigid stand to hold it in position. I built a stand out of laser-cut acrylic. (I made it at TechShop. www.techshop.ws) The result is a handy microscope that's easy to use and cost well under fifty bucks.
Step 1: Tools and Materials
1 - USB microscope. A good place to start is to search eBay for "USB microscope". Often they are advertised as having 20x to 200x magnification, with some as high as 800x. Most have either four or eight LEDs on the front to illuminate the subject. Beware: the one I got claimed to have 1.3 megapixel resolution, but it was really only 640x480 with post processing software to enlarge the file size. When I pointed this out to the vendor, he promptly refunded half my money, so the microscope cost me only about twelve bucks! The price on eBay for these scopes is about $20 to $30 including shipping from Asia. Yes, you'll have to wait 4 to 6 weeks to build this project!
2 - Macro Focusing Stand. Search for "macro focus". They are often described as "two-way" for a single axis. The one which fits the acrylic stand described here usually has the brand "Fotomate" printed on the unit opposite the adjustment knobs. Expect to pay about $12 including shipping.
You'll also need the following tools and materials:
- laser cutter
- acrylic sheet, 9" x 12"
- cement for acrylic plastic
- dispenser for acrylic plastic cement
- clamps to hold assembly during gluing
- long nose pliers
- hot melt glue gun and glue
- small cable clamp, the right size to fit your microscope cord
- 4/40 machine screw. 1/4" long
- #4 flat washer
- 4/40 tap, tap wrench and #43 drill bit (0.089")
- self-adhesive silicone feet