...one source for a ring...

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Tonikon
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...one source for a ring...

Post by Tonikon »

Hello everyone,
some time ago, I bought a Wild M3 series stereomicroscope on ebay and I found in combination with it a Leica ring light without the proper light source. I suppose the light sources were halogen at that time. Now, I would like to build a powerful and cheap LED light source myself, because I imagine that commercial solutions are quite expensive.
The optical fiber attachment shows a diameter of 15mm, which I think is the standard size for this sort of fiber. Any advice on how to save time and frustration in DIY?
Ciao
Toni
Attachments
Leica LedRing 01.jpg
Leica LedRing 02.jpg

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Scarodactyl
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Re: ...one source for a ring...

Post by Scarodactyl »

A name brand 150w halogen light source with a working bulb can be had for 40 bucks or so on eBay. 15mm is pretty standard so a few brands should work. You will probably get much better results that way.

Pau
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Re: ...one source for a ring...

Post by Pau »

A second hand halogen light source is the easiest way, like Scarodactyl suggests. This is what I use.
It will provide lots of light but also noise, vibrations and heat, of course.

You can also profit your nice fiber optic ring with a powerful LED placed very close to the fiber optic tip, this has been discussed in a long thread here
viewtopic.php?f=25&t=31950
mainly from this post
viewtopic.php?p=197481#p197481

Another option, of course, is a LED ring. There are very inexpensive rings for car headlights called angel eyes
Pau

Tonikon
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Re: ...one source for a ring...

Post by Tonikon »

Very well,
then I start looking for a second hand halogen illuminator. Unfortunately, I will have to accept the problem of vibration and heat, but the use of this ring of light will be quite occasional and not worth spending too much time on building a self-made apparatus.
Thanks for the very useful information.
Toni

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Scarodactyl
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Re: ...one source for a ring...

Post by Scarodactyl »

The nice thing is the vibration and heat are isolated from everything else.

Chris S.
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Re: ...one source for a ring...

Post by Chris S. »

Toni,

Before you buy a second-hand illuminator, it would be good to confirm what brands use a light guide with a 15mm end. My Schott-Fostec illuminators (a very common brand) all use light guides with a 18.2mm end. While a smaller 15mm end would certainly go in, I think the fit would be a bit sloppy.

Looking just now, it appears that perhaps Dolan Jenner illuminators use 15mm? (See page 8 here.)

My particular approach to isolating the vibration is to have the illuminators on a shelf, suspended by rope from the ceiling, over the macro rig.

For "quite occasional" use--if high CRI is not important--I would be tempted to simply place a small LED flashlight against the light guide and secure it with tape. So long as the tape doesn't intrude too far onto the body of the flashlight (commonly used as a passive heatsink), this might work pretty well.

--Chris S.

Tonikon
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Re: ...one source for a ring...

Post by Tonikon »

Hi Chris and thanks for your great advice. Indeed, I have always reluctantly used halogen lamps (too heat...) and now that there are LEDs I would not want to go back.

I tried to combine a Fenix ​​flashlight with the Leica ring light and the results are more than good ... the only problem is that at maximum power of the flashlight the batteries (AAx2) do not last even an hour.

If I find a Led flashlight that can also be AC-powered, with a single expense I would have a flashlight and a light source for the microscope. I'll let you know!

Ciao

Toni

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Re: ...one source for a ring...

Post by Macro_Cosmos »

15mm is pretty standard. If you find a light source with greater than 15mm, you can easily 3D print or machine a small collar and tap an M3 thread, secure the guide with a short set screw. If it's say 16 or 17, too thin for that, just wrap it in tin foil. (I wanted to make a tin foil hat joke, I must hold the urges)
Likewise, anything that won't melt under that kind of heat is good.

If you want something really good, this illuminator from Thorlabs is terrific: https://www.thorlabs.com/newgrouppage9. ... =OSL2#5634
I don't see any vibrations even with a high power objective.

Your ring light is 15mm, so you also need this: https://www.thorlabs.com/thorproduct.cf ... mber=AD15F
Sometimes they can be found on ebay for $10. I have various sized ones for the myriad of optic fibre light guides, they are usually so cheap, I just can't resist $10 a pop.

I also saw one of these:
123.jpg
It shouldn't be too hard to DIY if you have background as an electronics hobbyist.

Or, just use one of simplest methods. Duct tape the ring light onto a handheld LED torch. :D I've done that, as long as it works.

lothman
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Re: ...one source for a ring...

Post by lothman »

for 20$ you can get a LED ringlight for microscopes and for 50$ you can get one with different zones. I use such a ringlight on my Leica-Wild M3Z.

https://www.ebay.de/itm/AmScope-Compact ... OSwe~lcFHa~

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Scarodactyl
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Re: ...one source for a ring...

Post by Scarodactyl »

Halogens produce better light than a cheap led ring light. I have a ton of the led ring lights (got a big box of brand new ones years back I'm still getting rid of) and I think they are a great inexpensive addon for any stereo, but for more serious work I'm halogen all the way. I have like five of the sources on my desk attached to various light guides. Maybe I have a problem but at least it's a cheap addiction vs others in microscopy.

Tonikon
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Re: ...one source for a ring...

Post by Tonikon »

Hi everyone,
usually I put the stereomicroscope into action only to observe the specimen which I will photograph with a completely different system (a vertical setup with modified bioogical microscope and wemacro MicroMate). So, the illuminating system is important but not vital. I have used a Marcel Aubert halogen illuminator for years, built like a tank but very noisy and with more vibrations than a washing machine! But now it doesn't work well anymore and I would like to use a light source that is powerful enough for viewing only ... the idea of ​​using the ringlight is oriented to have no impediments when handling the sample and also to obtain an axial light, with few shadows. Medical solutions (like the excellent Thorlabs indicated by Macro-cosmos ...) are numerous and very good, but really too expensive for my occasional use. So, I would have thought of a DIY system that should combine economy, compactness (I have little space on the desk where I keep the stereomicroscope) and efficiency (at maximum magnification, the Wild M3Z needs a lot of light), but I still can't find inspiration. ..I also tried with a bicycle headlight ... the power is impressive but it heats like an oven and cannot be A/C-powered ... only with a large rechargeable battery connected with a long cable ...
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Wild M3z.jpg

Duke
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Re: ...one source for a ring...

Post by Duke »

Fancy... What is that objective slider? I was looking for one of those for my stereo.
“Thoroughly conscious ignorance is the prelude to every real advance in science.” - JCM

Tonikon
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Re: ...one source for a ring...

Post by Tonikon »

Duke wrote:
Mon Dec 14, 2020 10:52 pm
Fancy... What is that objective slider? I was looking for one of those for my stereo.
It is the very uncommon "Type-S drive housing", a translator designed to align the optical axis of the main lens with the optical path of the camera...
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Type-S drive housing
Type-S drive housing

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Scarodactyl
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Re: ...one source for a ring...

Post by Scarodactyl »

Very nice setup! About as tricked out as an m3 can get.

Chris S.
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Re: ...one source for a ring...

Post by Chris S. »

”Tonikon” wrote:I tried to combine a Fenix flashlight with the Leica ring light and the results are more than good ... the only problem is that at maximum power of the flashlight the batteries (AAx2) do not last even an hour.

If I find a Led flashlight that can also be AC-powered, with a single expense I would have a flashlight and a light source for the microscope. I'll let you know!

(snip)

I also tried with a bicycle headlight ... the power is impressive but it heats like an oven and cannot be A/C-powered . . .
Toni,

Making one's own adapter to run a small LED flashlight on AC power would be pretty easy, though of course dangerous if wrongly done. In your shoes, I'd be very tempted to make a battery "substitute" out of a wooden dowel cut to the length of two AA batteries, plus a screw for the positive terminal, a bit of wire, and a 3-volt AC power adapter. I'd take the rear cap off the flashlight and use an alligator clip to fix the negative wire to the flashlight's case.

The obvious alternative is to do as Pau and Macro_Cosmos have suggested: Buy and integrate an LED COB, heat sink, and power supply. The project doesn't have to be as elaborate as Saul's impressive work (linked to in Pau's post). Saul used a bright LED that puts out a lot of heat, so he used an active ("with fan") heat sink. A lower-powered LED can get by with a passive ("fanless") heat sink.

Your bicycle headlight would normally be used on the handlebar of a moving bicycle, so the designers likely expected constant airflow without need of a fan. Your Fenix flashlight is likely designed without such an expectation, and probably uses the battery tube as a passive heat sink. Nice passive heat sinks for LEDs are easy to buy over the Internet, and there are guides that tell you how much heat sink you need for a given wattage. Just make sure you put heat-conductive paste ("heat sink paste") between your LED COB and the heat sink. Also make sure that you buy a current-limited driver to supply the electricity without risk of LED thermal runaway. I've been experimenting with LED COBs and heatsinks, and I soldered a thermocouple to the LED COB to make sure the heat sink was adequate.

If the above paragraph seemed dense, there was a point. It lists the basics of what one needs to know to integrate a bare LED COB, and provides search terms. It's not a great deal of knowledge, but does take time at first--likely a few evenings of reading and experimentation for many of us.

Which is why integrating a flashlight has appeal: A decent flashlight already has a heat sink and current regulation built into it. Just now, when I tested a Conroy UV flashlight with my lab power supply attached in much the manner described above, I set the voltage to 3.6V (the flashlight is designed for a single 18650 battery), the light pulled a constant 0.2 amps. I think this confirms that there is a driver in the unit limiting current draw. And my several LED flashlights--used daily--dissipate heat just fine.

--Chris S.

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