Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Let's talk about Lighting

All about lighting. LED, CFL, Halogen, Other? Questions and info about lighting go here.
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ceeann1
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Re: Let's talk about Lighting

Post by ceeann1 » 21 Jan 2011, 13:12

Hey, Just a quick post from work.

Daniel, you sold me on the arduino/buckpuck <LED> combination for lighting some time ago. Sorry I didnt post this sooner. Buckpuck looks ideal.

Been a little busy, been trying to start qualifying for radiology (industrial version)... gotta go.

Ceeann

<edit>
The buzzer caught me on break for the above. I am learning how to x-ray aircraft bits-n-pieces. I need 400 hours On the Job Training and 40hrs of class. It looks like all the OJT will be overtime. Its nice to be paid but it makes for a long week. I am sure lots of folks can relate. I have some hours but it takes time...

photoman290

Re: Let's talk about Lighting

Post by photoman290 » 21 Jan 2011, 19:30

]The buzzer caught me on break for the above. I am learning how to x-ray aircraft bits-n-pieces. I need 400 hours On the Job Training and 40hrs of class. It looks like all the OJT will be overtime. Its nice to be paid but it makes for a long week. I am sure lots of folks can relate. I have some hours but it takes time...
[/quote]
if i used aircraft a lot, which i don't any more i would feel quite reassured by that :lol:

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daniel_reetz
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Re: Let's talk about Lighting

Post by daniel_reetz » 22 Jan 2011, 23:11

Cool, I'm looking forward to having you back on the forum, ceeann1. Good luck with radiology - I'd love to play with those kinds of imaging systems.

Thought you guys might like to see this. These are some LED-based MR16 replacement bulbs that I bought at an electronics surplus store. The one on the left is a "Neutral white" LED. The one on the right is a "Warm White". They both have decent color rendition (judging this just by eye) -- but if you haven't seen a Warm White LED in person, it is a bit shocking to see such warm-colored light coming from this kind of source. I'm sure people are going to ask which is better for book scanning - in my opinion, the Neutral White variant of almost any LED is going to be the best, but if manufacturer-spec'd CRI ratings are available, whichever has the better CRI should win.
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Koyaanisqatsi

Re: Let's talk about Lighting

Post by Koyaanisqatsi » 19 Feb 2011, 00:51

Hi all,

This is Mark Chester of Chester's Garage (linked earlier in this thread). I've noticed a significant amount of traffic to my site from this forum and I just wanted to offer that if you folks have any questions about LED lighting, please let me know - it's what I do when I'm not working my day job.

White LEDs are an interesting breed because they really are mostly a band of blue and a band of yellow (actually yellow-green through orange) light - roughly opposite colors that appear white when mixed together. The reason the warm white give better CRI than the neutral or cool whites is because the "yellow" portion of the light is brighter and covers a wider range of the color spectrum. But they are all missing large chunks in the blue-cyan-green range and past the red-orange end.

If you're looking to improve the CRI for color scans, you may want to consider a combination of Warm white, Cyan and deep red LEDs. This will give you 4 good points on the color wheel with opposing colors. And it will work well whether you're scanning in RGB or CMYK.

I could go on an on about this stuff, but I'll cut it here. Feel free to ask me questions about power systems or whatnot too. You might also check out my blog post about planning your LED circuits and powering them. http://www.chestersgarage.com/blog

Cheers!

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Re: Let's talk about Lighting

Post by daniel_reetz » 19 Feb 2011, 03:01

Mark, thanks for dropping by and enlightening us. Do you have any posts specifically about CRI and the color issues involved? I realize you probably want to keep most traffic going toward your own site, but deep, technical discussions of LEDs are more than welcome here. I usually rely on my color science books and discussions at CPF to get my technical fix.

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Re: Let's talk about Lighting

Post by Ryan_phx » 25 Feb 2011, 22:55

daniel_reetz wrote:
Ryan_phx wrote:One other question: I have an old laptop power supply that outputs 18.5V, 4.9A, 90W. The Cree Q5 needs 3.7V, so I should be able to run 5 of them off this power supply, right? Or am I misunderstanding something fundamental here?
Sounds right to me. With the BuckPuck you should be fine. Better to work in even numbers though - I think 4 will be plenty for your setup.
I've got 4 Crees wired up to a Buckpuck, and an old laptop power supply to power the thing. One final question: when I cut the end off of the power supply, there was one wire in a sleeve, and other loose wires wrapping around that. Is the wire in the sleeve the + (red) and the wires wrapping it the - (black)? Or is that backward?

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Re: Let's talk about Lighting

Post by Ryan_phx » 26 Feb 2011, 14:10

Ryan_phx wrote:
daniel_reetz wrote:
Ryan_phx wrote:One other question: I have an old laptop power supply that outputs 18.5V, 4.9A, 90W. The Cree Q5 needs 3.7V, so I should be able to run 5 of them off this power supply, right? Or am I misunderstanding something fundamental here?
Sounds right to me. With the BuckPuck you should be fine. Better to work in even numbers though - I think 4 will be plenty for your setup.
I've got 4 Crees wired up to a Buckpuck, and an old laptop power supply to power the thing. One final question: when I cut the end off of the power supply, there was one wire in a sleeve, and other loose wires wrapping around that. Is the wire in the sleeve the + (red) and the wires wrapping it the - (black)? Or is that backward?
And the correct answer is that the middle wire is positive, and the outer wires are negative.

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Re: Let's talk about Lighting

Post by Ryan_phx » 02 Mar 2011, 19:58

I just wanted to put a note here for future reference. I'm using a LED light rig using 4 Cree Q5s and a BuckPuck--you can see it on my build thread. I can safely say that it's easy to build, and provides plenty of light. I'm happy to provide any info I can to anyone considering a similar setup.

hg1027

Re: Let's talk about Lighting

Post by hg1027 » 10 Mar 2011, 15:45

I'm not sure I understand the three choices of BuckPuck.

I get the first one, -N, that's on/off only. This seems to be a good solution for lights that will be supplemental to room lighting. The LEDs would not be on at all during page turning, etc.

The third one has a potentiometer in it, which means you could turn it down if you wanted. I don't see a particular use for that here.

The second one seems to be preferred, with its "external dimming," and I assume it's what Daniel used in his low light/full light arrangement? Or maybe he adjusted voltage. I can't find that thread right now, but it seems most useful.

From a glare standpoint, it seems it would be easiest to have the half/full possibility and scan in a dark room.

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Re: Let's talk about Lighting

Post by daniel_reetz » 10 Mar 2011, 16:01

External dimming is the potentiometer option - if you connect the +5V output of the buckpuck to the control pin, it turns off. If you have a resistor on it, you can adjust the level. You can have a switch with a resistor on each pole, which will give you a medium and high level. Does that make any sense? Sorry, I'm tired and not sure I'm being totally coherent.

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