The instructable shows how to adapt an ordinary eye loupe to an illuminated LED eye loupe. After I made one, I was surprised at how much better the magnified objects look due to the illumination.
Step 1: Components and Tools
1. SMD White LEDs PLCC package - 8 numbers
2. SMD Resistors 100 Ohm 1206 or 0805 size: 8 numbers
3. copper clad board (stock PCB), cut an annular shape (see the next step for the dimensions)
4. ordinary eye loupe
5. Battery holder (4xAA battery holder)
1. Multistrand connecting wire with plastic insulation, 2 colors - 1 feet each
2. Instant glue
3. Solder iron and wire
4. wire cutter
Step 2: Make the PCB
Measure the diameter of the lens and the diameter of the rim of the loupe. Let A be the diameter of the lens and B the diameter of the rim. The inner diamater (ID) Of the annular PCB should be equal to A and the outer diameter of the annular PCB should be equal to B.
An eagle brd file for our annular PCB can be downloaded from this instructable and used as is or modified for your particular loupe dimensions.
We used a Modela milling machine to cut the PCB, but with a bit of effort and patience, you can actually do it manually with a drill machine and dremel tool to separate the copper in two circular concentric bands.
Step 3: Solder the LEDs and Resistors
Solder the LED and the resistor at right angles as shown in the photograph. You would need 8 such LED-resistor pairs.
Ensure that the resistor is soldered to the LED Anode. You dont want a mix of pairs with resistors soldered to the LED cathode.
Step 4: Soldering the PCB
After you solder each pair, test that the LED lights up with the help of a digital multimeter (diode test mode) so you are sure that soldering hasnt damaged the LED.
Step 5: Glue the PCB and Connect the battery!
I did not use a switch to turn the LEDs off and honestly it was an oversight. You could place an On/Off switch in series to turn the LEDs off, I just remove a battery from the battery holder to turn it off.
How does the illuminated LED eye loupe fare?
Check it out yourself in the next slide!