I really want a ringlight, and since I'm pretty good with LEDs, circuits, and soldering I cam up with this little DIY project. I got the idea here - http://brainerror.net/texts/howto/macroring/ and am making some modifications

Right now a majority, of my lenses take 58mm filters (18-55, 100, and 70-300).

Supplies
58 to 77mm Step Up Ring
White LEDs (I used 5mm Wide Angle)
100mm 1/2W resistors
9V battery
Wire (I used 22AWG)
5mm or 3/16" drill bit + drill
Solder and soldering iron

I just ordered an ebay 58 to 77mm black aluminum step up ring and 20 LED w/ resistors. I decided on 9V for the ease of finding batteries.

I have not decided how many LED's I'll use yet (maybe 12), but I know I will use them in pairs using the folowing diagram:

Code:

Solution 0: 2 x 6 array uses 12 LEDs exactly
    +----|>|----|>|---/\/\/----+  R = 100 ohms
    +----|>|----|>|---/\/\/----+  R = 100 ohms
    +----|>|----|>|---/\/\/----+  R = 100 ohms
    +----|>|----|>|---/\/\/----+  R = 100 ohms
    +----|>|----|>|---/\/\/----+  R = 100 ohms
    +----|>|----|>|---/\/\/----+  R = 100 ohms

The wizard says: In solution 0:
  each 150 ohm resistor dissipates 60 mW
  the wizard thinks ¼W resistors are fine for your application
  together, all resistors dissipate 360 mW
  together, the diodes dissipate 792 mW              
  total power dissipated by the array is 1152 mW      
  the array draws current of 120 mA from the source.

I'm going to be drilling 5mm holes in the step up ring to mount the LEDs. Each LED has a viewing angle of 120 degress which is good, but to even the light output for the "ring" I think I'll use a bead of hot glue.

7/19/08 - Proof of Concept
I'm second guessing my choice of wide angle (flat top) LEDs. They will help to project an wide light into the hot glue bead, but the light dies off quickly because of the 120 deg light angle. If I try in the future, I may use regular LEDs. Also 3mm should work well, no particular reason I went with 5mm.

I got my LEDs and did a very raw, ghetto fab mock up to see if it would work. I used a piece of cardboard to mount the LEDs in a ring, then I use wire and a lot of electrical tape to complete all the circuits. I only used 16 LEDs in the test.

I switched my mind from using 150 Ohm resistors to a 100 Ohm resistor. I can use one 1/2W 100 ohm resistor on all 20 LEDs. At 100 ohm each LED is running at 3.5V (max voltage) compared to 3.3V using a 150 ohm resistor.

This light is not intended to be a flash replacement, I mainly wanted the ring for eyes when lighting it otherwise ample. Also, it should add some additional white fill light for macros in dark situations. My initial tests show that I get great LED lighting about 6-7 inches using 100ohm. Using the 150ohm (3.3V), it seems more like 4-5 inches. These were just very raw tests as many variables will determine the effective range (how LEDs are mounted and oriented, hot gule bead, etc).

Here are some pics of the ghetto fab proof of concept build. The final will look NOTHING like this LOL





I'm currently waiting on the 58-77 step up ring to arrive.


8/4/08
Ring came in today and I got to work!

Step 1, drill holes. 5mm drill bit would have been nice, but I had a 3/16" so I gave them a little wiggle


Step 2, mount LEDs and solder together. I bent all LEDs the same way then arranged them in series of pairs. Positive to the right, Negative to the left.


Step 3, wiring. So I got the idea to take a thumb tack and put holes in my wires then slipped them over the positive legs. put a dab of solder on the ends.


Step 4, wire negative. slap on a resistor and try it out.


Lights out!


Step 5, hot glue. I put a bead of hot glue to hold all the LEDs and wires in place. It also protects the circuit and my finger from snagging on the LED legs. A bead on top distributes the light more evenly.

Its not the prettiest thing ever, but it works!



Initial results are that the LEDs are so white, they're almost blue. It puts out a good amount of light. should be interesting to use for random projects. Not bad for $10.

Its not the prettiest thing in the world with the hot glue, but it gets to job done!




after this shot, I pulled the hot glue off the front. it was dimming the light too much for the small amount it was helping disperse the light

woah, can't wait to see how this comes out.

I've seen something similar done with the LED flashes off disposible cameras. Let us know how it works out though. I'm interested in one.

yeah I saw the disposable camera one. It was pretty big and those capicators can be dangerous if not careful.

I'm interested in this idea as it really won't be a flash, but a constant ring light. It should also help with focusing.

Originally Posted by PhatheadWRX

and those capicators can be dangerous if not careful.

isn't there also a DIY disposable flash taser mod?

egg-zachery

I had a friend who knew how to rig door handles into booby traps with them

Good luck, can't wait to see how this works out

Originally Posted by jacobsen1

isn't there also a DIY disposable flash taser mod?

oh jesus christ.


When I was young, I LOVED going to "AX-Man" which was a kick ass random parts store. They sold the most RANDOM ****. Anyways I once bought a disposable camera flash board.


I then ran 2 wires from the 2 capacitor legs to my bedroom doorknob.


My dad grabbed the handle...


Oh dear god, I thought I had maimed him with the shouting that went on.

ill be interested to see how much light you get out of a 9v battery
the ones we have at work are over driven industrial LEDs with 24V - and they barely do anything

well the supply voltage (9 vs 24) doesn't really tell you anything about the light output. Its all about the LED specs. Mine are 4,000-5,000 mcd at 3.3-3.4V

You could be using the same LEDs, but at 24V you'd have 7 hooked in series to each resistor. Comapred to my 2.

I bought 20, so in I could theoretically have up to 100,000mcd. I think I'll start using 10, then add more until I'm happy with the light.

I know its not going to be anywhere near strobe strength or range.

Originally Posted by PhatheadWRX

I know its not going to be anywhere near strobe strength or range.

*goes to do some DIY ghettofab on his halloween strobe lights*

Originally Posted by PhatheadWRX

well the supply voltage (9 vs 24) doesn't really tell you anything about the light output. Its all about the LED specs. Mine are 4,000-5,000 mcd at 3.3-3.4V

You could be using the same LEDs, but at 24V you'd have 7 hooked in series to each resistor. Comapred to my 2.

I bought 20, so in I could theoretically have up to 100,000mcd. I think I'll start using 10, then add more until I'm happy with the light.

I know its not going to be anywhere near strobe strength or range.

Unless you have multiple 9v's how much power do you think youll get out of one? Even if you can Drive that many, they need amps to run, and the 9V will be drained in a matter of minutes, if not seconds..Sure they are efficient, but not THAT efficient. You need a 9V wall wort to really get anywhere... unless Ive completely mis-read your OP and you have a huge 9V Lead acid battery, not one that goes into a smoke detector..

update

Also the 9V has been powering the ring for 10 minutes with no signs of drainage.

Originally Posted by user errors

I had a friend who knew how to rig door handles into booby traps with them

Good luck, can't wait to see how this works out

I used to work at a photo place and developed film (a one hour type deal), we'd take the flashes out and occasionally get a shock. That sucked.

It was fun to ahve a pocket flash though, you could easily blind people at any time.

Originally Posted by PhatheadWRX

update

Also the 9V has been powering the ring for 10 minutes with no signs of drainage.

cool, nice work so far. Do you plan to make some kind of cover to diffuse the light into a uniform ring?

yep, sorry if I wasn't clear, but I'm going to be putting a bead of uniform hot glue around the tops of the LEDs. It will help hold them in place, and it should perfectly diffuse the light.

Its been two weeks and the 58-77mm step-up ring still isn't here

Where did you order from?

e-bay china

Moved the steps to 1st post...

awesome! it is always on when the battery is hooked up?

ya, just a simple 9V battery connector. Plenty of wire so it's east to manage the battery

you should put that thing on a light meter and see how much light you get out of it...

Hi French, I thought this guy had some clever ideas...
http://fuzzcraft.fuzzphoto.eu/ringlights.html

thanks ken. that guy has some killer stuff. I totally screwed up going with 120deg wide angle LEDs on mine. They don't produce enough light.

I love to try to replace my LEDs with ultrabright regular tipped LEDs. I'm sure that would help. Just no time to try right now.

then there's this...I especially like the circuit board thingy.

Is that a UFO, or a milling machine?

Bunch O' White LED's...

Aluminum Ring Housing...


PC Board...

This fellow cannibalized a set of holiday lights he got for $12 to harvest the LED's. The PC Board wires 2 LED's in siries and then hooks each pair in parallel 22 times, for a total of 44 LEDs. The unit is powered by a 4.7v phone charger. Someone on the thread suggested that each pair of series LEDs ought to have a 1/8 watt 270 ohm surface mount resistor in series because in the current design, if an LED shorts out it could take a bunch of others with it.
Because the light surrounds the spindle at close range, you get a lot of illumination with minimal shadows, which seems ideal for mill work. Lights similar to this one are available on eBay for use with microscopes in the $60 to $90 range.

that PC diagram is the same way I have mine wired, but with a larger resistor and power source.

I really wish I could print something like that, it make wiring this thing so much easier and cleaner.

the fiber optic flash is awesome, i wish i could build it.

Originally Posted by distorto

the fiber optic flash is awesome, i wish i could build it.

We sell them at work
I got an old and am in the processes of modding it to fit a 77mm filter