WARNING !!!!! The device I am about to describe the construction of is NOT of medical grade NOR should it be used to make absolute determination of any condition whatsoever. Trained use in detection, and what one is actually looking at is also necessary to make a DIAGNOSIS, so this device should not be used to diagnose.

BTW: this item is a homemade version of a device used by my dermatologist to do an exam on me.

The device is to be used to merely help provide a possible prewarning of a condition that should be checked out by a doctor.
Skin cancers are SERIOUS business. It is modeled after the polarized light device my dermatologist used to examine my skin lesions. Your skin is the largest organ of your body, and it is the entire body's first strike defense and protection against all types of invaders.

With this in mind, the following device "could" possibly help one discover that one may have a precancerous or cancerous condition that is completely treatable, if taken to the doctors right away.   It is NOT meant to bring about panic of any sort; The instructions here however could help you get that early treatment needed to safely remove the carcinoma (precancerous cells as in basal cell or squamous cell carcinoma).

Step 1: Parts and Warnings...

*****WARNING***** When gluing on the lens(es) do NOT use any glue that gives off strong fumes while curing.

I ruined a pair of polarized lenses by gluing them with Super Glue. The fumes clouded and otherwise ruined the lenses. A small dab of Gorilla Glue works great.

Needed:

One polarized lens; two if you want to fiddle with different "grades" of polarization
a piece of plastic pipe fitting that will house the lens
one micro-pushbutton switch (push on, momentary contact)
a tightly fitting rubber "grip"
some fumeless glue
a BRIGHT or SUPER BRIGHT LED
some wire,
pieces of copper
two coin batteries
a bit of compressed cardboard, etc.

Step 2: Assembly

As I attempted to fit this all together, I needed to improvise a lot. Depending on the size lens you get and the size pipe it fits, you will have to also.

I made a lens holder by hack sawing a ring from an old pill bottle.

To make a coin cell holder, I used the plastic cap from a water bottle, trimming the edge away, and hot gluing in a piece of copper I soldered to a wire (negative side of the batteries).

I used another piece of copper for the positive side of the batteries, and wired that to the switch.

The LED was centered by running the LED legs through a piece of stiff cardboard, and gluing the bottom of the LED to it.

The Grip I cut in half, using one half at the upper section where the lens is, and the other to hold the constructed battery holder on.

I drilled out the side of the tube to place the button switch in.

Step 3: Use

AGAIN, this is not anywhere NEAR a medical grade device, and extensive training is needed to DIAGNOSE skin cancer, but some things to take note of or look out for, to make your dermatologist aware of potential problems.

#1: irregular shaped moles or markings
#2: moles that change shape or grow rather rapidly
#3: oddly shaded (brown to red, etc) moles

The polarization of the light, helps bring out the odd asymmetrical shapes of carcinomas and skin cancers.

Step 4: Apendix

For those that wish to make an adjustable one, insert a second lens into the rubber holder (in front of the lens attached to the pipe) so that rotating the rubber grip will change the angle of polarization of one lens to the other (this will limit the light going through the lenses also, until a 90 ^o change blocks most if not all of the light. Not so useful for detection, but maybe for further experimentation for other things.