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Cheap Bench USB Microscope

pandaemoniumPandaemonium wrote 03/01/2016 at 01:47 • 6 min read • Like

This is my first full post of a hack (nay, an innovation, says you the reader), I realize I will make mistakes in it's presentation but I will endeavor to clarify my future ominous basement doings more clearly based on the kind comments of the bored readers who graced this page in desperation for something to do. I thought it best to make my first post one of simplicity, yet usefulness. If all works well, perhaps I will deign to subject you to the terror of 40 years of basement dwelling triumphs!

Here's a cheap bench USB microscope that is easy to make and works quite well with a few modifications and can be adjusted to any position. The microscope itself is seriously lacking in many aspects, but for most tasks, including P.C.B. oggoliong it works well enough once the microscope's short-comings are either corrected or you learn your way around them.

I Started with a Celestron 44302-A "Deluxe Handheld Digital Microscope" they cost around $25-$50 CAD/USD. The best part of this microscope is the base, it's nice and heavy and is probably useful for something, unscrew the microscope clamp from the base and toss the base into the junk bin for another project someday.

You will need to drill a 3mm-4mm hole through the center of the microscope clamp where the base screw was inserted, a screw will be inserted into the hole from the front, and sticking out the back by 20-30mm so. Counter-sink the hole (carefully) so the screw head will not interfere with the clamp's ability to hold the microscope.

I then picked up a desk lamp (about $15 CAD/USD), a Globe Electric 52061-T20L will do, just look closely at the hood mount of the lamp, you will want it to be the same kind, it is used on several models, so getting one shouldn't be a problem. The main difference in models using this hood mount is the shape of the hood and the color, those things are unimportant, only the mount matters here.

Remove the light socket from the lamp, as well as the A.C. cable, then remove the hood mount flange by removing the screws and then drilling dead center down the middle of the flange with your 3mm-4mm drill bit, then force it out. Careful, and use common and un-common sense (common and inversely un-common sense are the true sixth sense, use that power wisely).

Once the hood mounting flange is removed you will be left with a stubby little socket, the I.D. of this socket is very close in size to the O.D. of the stubby protrusion of the microscope clamp in which the nice microscope base was mounted.


When choosing a lamp, make sure the mount looks as in the picture below (though it is minus the flange mount).

Put the screw of your choice into the microscope clamp so it comes out the back, insert the clamp and screw through the socket of the lamp arm hood flange mount, ah, a perfect fit! You may need to trim down the length of the screw so that motion is not inhibited. Use a small flat washer and a lock-nut to hold it in place and carefully adjust the nut for correct tension (by feel).


Mods:

Did you see the switch in the body of the microscope in the last two pictures? Ya, USB power is usually on, so unless you like your microscope glaring at you even when the computer is turned off (or if you just want to save power, I guess), then you will need a way to interrupt the power; I do this with something called a "power switch"

Simple enough, just insert a small switch to cut the V+ line on the USB. The top cap on the microscope just pops off with a good pull. I know I am horrible at using epoxy, that was my first time, I know better now (I went decades without ever using epoxy, I used to machine everything, just got old and lazy), and the soldering, though not poor by most standards is less than perfect and is remarkable considering the dubious origin of the wires. Never-the-less, this is an on/off switch, there, all that dialog leading up to that!

This microscope has illumination, can you believe that? Yup, as you can guess, since I brought it up, there must be something wrong with it. Yes, it kind of sucks, it's poorly diffused so it gives a crap image of up-close images, and since that's the whole point, well let's just say: I assume it was designed correctly, but that accounting got involved and had all the LEDs changed to a cheaper solution; so only the accountant needs to be face-slapped, not the engineer.

Pull them all out like rotten teeth (no, no, de-solder them properly, and note the cathode-anode orientation), these are through hole, so this is a breeze. Get diffused white LEDs to replace them. Get two slightly different wave-lengths of LEDs (half warmer, half cooler) and put in one or two U.V. LEDs, you will be able to see way more that way.

LED Diffusion

You can buy diffused LEDs, but often the process involved will result in a uniformly dispersion of photons. Dipping the LED body in acetone and then quickly rubbing it with a cloth sometimes works. stuffing LED consoles with cotton can work sometimes. Look online for techniques, proper lighting is the biggest limitation with this setup, as is with all photography no mater how good the equipment is.

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