This is sort of a sequel to my Instructable: http://www.instructables.com/id/Ultra-Bright-24-LED-Lighted-Magnifier/ That Instructable described a lighted magnifier that runs on AC power, to get maximum brightness without worrying about charging or changing batteries. I use that magnifier all the time. In fact, I've made three of them, and keep one in each of my work areas. But sometimes I really need the portability of a battery-powered magnifier.
This new magnifying glass has a bright array of 15 LEDs producing 37500 mcd. It has an optical glass lens with about 3.5x magnification. The handle was made on a CNC machine from European beech hardwood.
And it has a power supply using four lithium cells to provide years and years of regular use without having to think about the batteries! (If I use it every other day, keeping the light on for a full minute every time I use it, the batteries will last more than six years.)
I made it at TechShop. http://techshop.ws/
Step 1: Tools and Materials
The lens was an "experimental grade" lens to keep the cost moderate. I chose a focal length of 141mm, which yields about 3.5x magnification. You can select a lens to give you more or less magnification, but if you get much higher than 5x, the spherical distortion will start to be a problem.
The battery pack consists of a PCB (which you'll make yourself) and four individual battery holders. No one seems to make an off-the-shelf 4-cell CR123 holder. The PCB also keeps the wiring simple.
This project requires the following parts and materials:
- Angel Eyes 60mm LED array. http://www.superbrightleds.com/moreinfo/led-headlight-accent-lights/led-angel-eye-headlight-accent-lights/49/
- lens, 45mm diameter, 141mm focal length. I used part number AX75519 from Anchor Optics. http://www.anchoroptics.com/catalog/product.cfm?id=268&s=focal_length&d=d
- copper clad board for PCB (FR-4, 0.031 thickness, 1 oz copper clad one side)
- etchant for PCB
- CR123 battery holders, 4 ea. DigiKey part number BH123A. http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&KeyWords=bh123a
- four CR123 batteries
- momentary pushbutton miniature switch with mounting hardware
- insulated hookup wire, 22 gauge stranded
- shrink tubing, 1/4 inch
- double-sided foam tape
- wood for handle/housing (see text)
- 5 minute epoxy glue
- silicone adhesive
- two #2 brass flat head wood screws, 7/8" long
- wood finish of your choice (I used polyurethane)
You'll need the following tools:
- ShopBot (or other) CNC router
- appropriate CAM software
- router bits or end mills (I used 1/8" and 1/4")
- drill press
- drill bits: #60, 1/16", 5/64", 5/32" and 1/4"
- medium Phillips head screwdriver
- soldering iron and solder
- sandpaper (150, 220 and 320 grits)