Introduction: How to Make an Illuminated LED Eye Loupe

Picture of How to Make an Illuminated LED Eye Loupe

I have been using an eye loupe for viewing small electronic components, inspecting PCBs etc. However I was intrigued the other day when I saw this illuminated LED eye loupe at Sparkfun and I thought I should make my own.

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

Picture of 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

Picture of Make the PCB

Once you have all the tools and components, the first step is to prepare the PCB to solder the LEDs on.

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

Picture of Solder the LEDs and Resistors

Once you have the PCB made,  its time to prepare the LEDs. I had some white SMD LEDs in PLCC package. But the size is not critical. Any size such as 1206 or 0805 would do too. Although a larger LED package is easier to solder. Similarly, for the resistor, a large package is recommended although I used size 0805 since thats what I had and it wasnt quite easy to solder this tiny resistor.

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

Picture of Soldering the PCB

Mark out 8 equally spaced positions on the annular PCB and solder the LED-Resistor pair as shown in the photograph. Before attempting to solder the component, it is a good idea to tin the location with solder. This will allow the component to be soldered with a minimum of fuss and without too much heating of the components. Solder all the 8 LED-resistor pairs.

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!

Picture of Glue the PCB and Connect the Battery!

Once all the LEDs are soldered,  Glue the soldered PCB (with the LEDs facing away from the loupe) to the lens side of the loupe using instant glue. Take precaution to alighn the PCB carefully. Now, connect the battery to the PCB copper bands. Observe the polarity while soldering the battery to the PCB.

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!

Step 6: Raison D'etre!

Picture of Raison D'etre!

See the photographs here for yourself, how well the illuminated LED eye loupe works.

I had great fun building it and even more fun using it. I hope you do too, should you decide to make one for yourself.

Thanks to Nehul Malhotra for the PCB job!


GenViper (author)2012-07-13

You, Gadre, are an inspiration; I never even CONSIDERED something like this before, but I took your idea and ran with it. I may put up a Instructable soon, but until then, it seemed only right that I share this here.

I designed a coin cell holder, and made a system to add a small momentary switch; the entire system is now contained on the loupe itself.

Gadre (author)GenViper2012-07-14

Oh this is awesome! Please go ahead and publish this as an Instructable!!

5Volt (author)2010-03-01

The PCB could be made with a circular (cup) drill saw (or what-is-its-name-in english), a vertical drill and some copper clad board. No PCB etching required.

Clamp steadily the PCB to the vertical drill; drill out the smaller (inside diameter) with an appropriate diameter circular drill saw, then with an intermediate diameter circular drill saw scratch (do not cut) the insulating dip on the PCB then finish the ring with the larger outer diameter circular drill saw.
You'll remain with two concentric conductive rings on the copperclad board suitable to hold the LEDS connected in parallel.

Sorry, I'm missing some technical names for the things and I could not take advantage from wikipedia/google images...
Hola everyone !

Johenix (author)5Volt2011-03-29

5Volt, I believe the word you were looking for is "DRILLPRESS".
What is it in Espanole?
Your English is better than my Espanole.
Where do you hale from?

acelegna (author)2010-06-07

hi trying to do a very similar thing BUT i have the "bulb" leds with the legs instead of the square ones you're using. My question is: can i solder them the same way you're doing? (bend the legs ontop of the copper traces and solder).....or do i have to flip the curcuit board around, drill small holes and insert the LEDs and bend the legs towards the traces on the "bottom side"? Great job by the way :)

Gadre (author)acelegna2010-06-08

Sure. I just did a normal LED version for you. It was on my mind for a long time anyway. Sorry, the image quality is not that good as its taken with a phone camera.. Hope this helps.. -Dhananjay Gadre

Ps2playa (author)2010-05-25

kinda looks like the arc reactor in Iron Man

zack247 (author)2010-04-14

now if only i had an eye loupe... it looks almost like a car headlight in step 5's picture. this is cool  B)

michaelgohjs (author)2010-03-22

this is really nice
BIG BIG diffrence good for dark indoor workshops (how most are) 

dadanr (author)2010-01-07

it is really cool loupe......a great idea for me to make sensor loupe to cleaning camera sensor.....thanks for sharing :)

fin saunders (author)2009-12-12

Ooh! Ooh! Ooh!

USB cable

fin saunders (author)2009-12-12

How about a momentary on switch.  One out of a mouse for instance?

That way it would only be on when you were holding it.   And forgetting to turn it off goes away.

Nice Instructable.

handprints (author)2009-12-04

 This is awesome!  I have been looking at fern spores and holding a flashlight and my handlens and holding the frond still has been very difficult. 

would you say this is a good project for beginning solderers?  Or should I go out and buy a new illuminated lens?  Even if it were more cost effective to buy a new one, I was thinking the experience would outweigh the extra cost (if any?)

What do you think?


Gadre (author)handprints2009-12-04

Thank you prosandy. I am sure it would be good fun to try it out. Soldering SMD components is not too much of a problem as long as you get largest size SMD resistors (1206 is quite common) and same goes for LEDs.

handprints (author)Gadre2009-12-05

 thanks!  a trip to radioshack is on the list of things to do today!

Gadre (author)handprints2009-12-06

You might have a better choice on digikey:

1. Loupe:

2. LEDs:

3. resistors:

handprints (author)Gadre2009-12-06

 wow! thanks!

Johenix (author)handprints2009-12-10

While at DigiKey (Yes, there is a Thief River Falls, Minnesota), take a look at Lithium Coin batteries and their holders. I think two 2032 batteries and a holder would mount very nicely on the side of the loupe. Also take a look at the switches they have for sale. I think we could find a nice little one that lies flat against the side of the loupe.

handprints (author)Johenix2009-12-11

Thanks so much for the ideas!!  I just made this terrarium out of a1/2 gal. round candy jar with a glass top.  It is in my office.  I think I will try out a ring for my terrarium.  I'm going to check out the spectrum of light that the LED puts out.  Wowee!  So excited.

Sabata (author)2009-12-10

Way cool. Gonna have to try this one.

askjerry (author)2009-12-10

A couple of pointers... stranded wire is better than solid core wire if it is going to be flexed, so for this project use stranded wire as it isn't as stiff, and not as prone to breaking. Another idea is to see if you can find an old wall transformer that outputs 6v. (The AA battery is 1.2 to 1.5v, so with four that's 5 to 6 volts.)

Even of you want to keep it battery powered... the cord from an old wall transformer is usually very nice stranded wire and a good way to recycle. You can often get this from old cell phone chargers... I have made many projects powered with recycled chargers!

For covering the LED's you can also use 2-part Epoxy which is generally glass clear. Just remember... if you do coat them in epoxy... it is NOT going to come off for repair! Also... if you go this route... apply it before you attach it to the eyepiece so you can trim it, and so you don't get epoxy on the glass while doing the job.


Vermin (author)2009-12-10

Coating the inside of the loupe with this stuff: would eliminate the internal reflections. I've used it to great effect on my telescopes.

dtoma (author)2009-12-08

I will use red led's and make 2 for the eye of my robot. Nice

orksecurity (author)2009-12-08

Definitely interesting. As my eyes have aged, I have been looking with lust at the lighted binocular magnifiers that my dentist uses. Those have the advantages of being designed to work over glasses, focusable for desired working distance, and so on. They also cost an arm and part of a leg. I can afford it, and it may be a good investment at my age... but this is a great "cheap and cheerful" version.

Any particular reason you used the surface-mount components rather than the more hobbyist-friendly wire-lead versions?

Gadre (author)orksecurity2009-12-08

There were a couple of considerations for using SMD components

1. Leaded components, I thought, would protrude too much below and interfere with the focusing range so to say.

2. Likely to damage leaded components more than the SMD components again, because of the extra protrusion.

3. The PCB layout (there is not much of a PCB layout really) with the SMD components is fairly simple. With leaded components it would get more messy.

jeff-o (author)2009-12-04

Oh!  I had another idea.  You could coat the LEDs and PCB with hot glue.  This would protect the LEDs from damage, and would diffuse the light quite nicely.

Gadre (author)jeff-o2009-12-04

You reading my mind Jeff-o? I have been contemplating that, my only concern was whether the hot glue would 'color' the LED light in any way. Last time I did that onto a high brightness LED, that happened:

You can see the yellow tinge on the hot glue.

Infact in a more advanced version I thought I might put in RGB LEDs and actually tailor the color of I light I wanted to have for a particular observation....

lieuwe (author)Gadre2009-12-04

 that shouldn't happen, you're sure you didn't overheat the glue(either with the gun or with the led)? my hot glue is perfectly white...

jeff-o (author)lieuwe2009-12-08

Yeah, it all depends on the type of glue you use.  Some types do yellow when they are heated (or when overheated) and some don't.

jam BD (author)2009-12-07

Handy =D

icebird (author)2009-12-04

This looks like the beginnings of an Ironman costume.

bjepson (author)2009-12-04

 I really like the way you prop up the LEDs with the resistors. I'll have to remember that trick.

Gadre (author)bjepson2009-12-04

Thanks Brian! I am glad you noticed.

jeff-o (author)2009-12-03

Great work!  I've been meaning to make something like this for a while.  I may also add magnets or clips so I can attach it to my glasses...

Gadre (author)jeff-o2009-12-03

Thank you. Adding magnets is cool. I also wear glasses and I just checked but the frame is non-magnetic. Maybe I will get another suitable frame.

jeff-o (author)Gadre2009-12-04

My normal glasses aren't magnetic either, alas.  I will have to rig up a clip of some sort for them.

lowercase (author)jeff-o2009-12-03

 This is amazing, great idea!!
The next thing I'd do is to mod the battery holders so you have everything into a single piece. Maybe you could use single battery holders, wire them in series and attach them to the body of the loupe at 90º angles each.

Gadre (author)lowercase2009-12-03

Thank you lowercase. Adding battery holder/s right on the LED PCB would be nice and would avoid the clutter of connecting wires. I would perhaps use button cells with vertical holders just to minimize the weight. AND I should add an On/Off switch as well!

bewakoof (author)2009-12-04

Awesome work there. Moreover, an excellent documentation

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