American Optical LED Conversion

Here you can discuss DIY adaptations to the microscope.
Post Reply
Message
Author
jb89
Posts: 101
Joined: Fri Jun 21, 2019 9:09 am
Location: Denver, Co

American Optical LED Conversion

#1 Post by jb89 » Fri Jun 19, 2020 1:42 am

I've had a little bit of free time between semesters and finally got around to finishing some projects I have been working on and this is one of them

I took my original AC-AC power supply for my AO 570 and converted it to a DC power supply, I changed the on-off bulb in the power supply to a nice blue LED and the light bulb in the main light is now LED as well.

This is the original circuit:
original_elec.jpg
original_elec.jpg (102.34 KiB) Viewed 4542 times
And this is the DC circuit:
elec_wired.jpg
elec_wired.jpg (103.02 KiB) Viewed 4542 times
I 3D printed an adapter to use a DC jack for the light as well as a bracket to hold the new electronics(sourced from a standard wall wart with appropriate voltage):
models.jpg
models.jpg (86.4 KiB) Viewed 4542 times
I also printed this circuit board vise and rack for my aux lenses. both of them are designed to work without any modification to the microscope stand:
20200618_192129.jpg
20200618_192129.jpg (62.24 KiB) Viewed 4542 times
And here it is all completed:
20200618_192053.jpg
20200618_192053.jpg (82.46 KiB) Viewed 4542 times

apochronaut
Posts: 6233
Joined: Fri May 15, 2015 12:15 am

Re: American Optical LED Conversion

#2 Post by apochronaut » Fri Jun 19, 2020 12:47 pm

That all looks very nifty but one of the problems I have had with led conversions( one, not the only) over the years has been the excessive blue shift in the light and a fairly flat contrast. It may not be a problem for certain objects, where colour faith is unimportant but for biologicals it is very important and contrast is always in vogue.Your emitter looks to be very blue. Is that by choice? Any idea what the colour temp. is? The photo looks like Morticia might peek in from the corner of the frame at any moment.

I was also wondering about the lumens output, the emitter size and how many of the condenser elements you retained in the illuminator nose. I realize that the original output of those illuminators is a bit wimpy , so my current solution is to use two of them connected to an AO dual transformer , with the second on an adjustable arm that can be postioned in order to obtain precise shadowing for relief structures or obtain illumination in depth that the mounted 18 watt doesn't penetrate.

I would be interested in converting over to led , if the previous problems I have encountered can be solved.

jb89
Posts: 101
Joined: Fri Jun 21, 2019 9:09 am
Location: Denver, Co

Re: American Optical LED Conversion

#3 Post by jb89 » Fri Jun 19, 2020 2:46 pm

The LED I'm using is quite white(neutral white), far better than the very warm white from the original bulb, I'm not sure why it looks so blue in the picture but there are quite a few different color temperatures available for LEDs

I have a standard 5mm LED rated at 15,000 mcd, I'm not sure how that converts to lumens but I would say it's about equal to the original bulb, I might upgrade to a much more powerful LED in the future, if I am at maximum zoom with a 1.5x lens I could still use more light in some cases

Here's an example looking at something
20200618_192101.jpg
20200618_192101.jpg (74.74 KiB) Viewed 4510 times

Zuul
Posts: 212
Joined: Fri May 01, 2020 9:01 pm
Location: California

Re: American Optical LED Conversion

#4 Post by Zuul » Fri Jun 19, 2020 4:00 pm

jb89 wrote:
Fri Jun 19, 2020 2:46 pm
The LED I'm using is quite white(neutral white), far better than the very warm white from the original bulb, I'm not sure why it looks so blue in the picture but there are quite a few different color temperatures available for LEDs

I have a standard 5mm LED rated at 15,000 mcd, I'm not sure how that converts to lumens but I would say it's about equal to the original bulb, I might upgrade to a much more powerful LED in the future, if I am at maximum zoom with a 1.5x lens I could still use more light in some cases
It looks blue in the photo because is very blue. Human eyes have an amazing capacity to compensate for these things. I’d guess that LED is at least 6000K, and possibly a lot higher. The original bulb was probably somewhere between 2000K and 2500K depending on how hard it was driven.

Candlepower (mcd) is a measurement of light hitting an area, and thus the lens on the LED makes a huge difference. Lumens are a measurement of total light emitted, and thus totally ignore how much light is wasted in the system. A 15000mcd 5mm LED is probably producing around 5 lumens, but doing a good job of making all of the light useful. A 10W incandescent will be on the order 400+ lumens, but a great deal of the light is lost. As an aside, high power LEDs (1W, 3W, etc.) not only produce a huge number of lumens, but they only emit in one hemisphere, so are immediately twice as efficient as incandescent in a system like a microscope where the lenses typically collect only the light emitted in one direction.

jb89
Posts: 101
Joined: Fri Jun 21, 2019 9:09 am
Location: Denver, Co

Re: American Optical LED Conversion

#5 Post by jb89 » Fri Jun 19, 2020 4:17 pm

Zuul wrote:
Fri Jun 19, 2020 4:00 pm
It looks blue in the photo because is very blue. Human eyes have an amazing capacity to compensate for these things. I’d guess that LED is at least 6000K, and possibly a lot higher. The original bulb was probably somewhere between 2000K and 2500K depending on how hard it was driven.
I thought I had ordered 4000K LED's but you're absolutely right, these are way off from where I expected these to be and just seemed to not notice.

It's for the time being still pretty nice but I would like to get my light a bit more accurate if I did go for a higher power LED

Zuul
Posts: 212
Joined: Fri May 01, 2020 9:01 pm
Location: California

Re: American Optical LED Conversion

#6 Post by Zuul » Fri Jun 19, 2020 8:25 pm

jb89 wrote:
Fri Jun 19, 2020 4:17 pm
I thought I had ordered 4000K LED's but you're absolutely right, these are way off from where I expected these to be and just seemed to not notice.

It's for the time being still pretty nice but I would like to get my light a bit more accurate if I did go for a higher power LED
In my experience, 5mm leds are rarely produced with good color control. I wouldn’t be surprised if those were sold as 4000k. The high power leds for lighting are much better in that regard. The emitters that are CRI rated can be very good. The trick is finding someplace that sells the good bins in small quantities.

Post Reply