Let's talk about Lighting

[reggilbert]

For those who know more about cost-effective LEDs for scanning than me:

Someone commenting on one of the DealExtreme Cree Q5 product pages said that it seems like the LED price/performance sweet spot is moving on from the XR-E Q5s to the Cree XP-G series, so I checked it out.

DX offers an XP-G R5 1B, which produces 350 lumens at 1A, for $6.74 (http://www.dealextreme.com/details.dx/sku.44305). A similar or possibly the same product is available at a site called LCK-LED.com (http://www.lck-led.com/p673/Cree-XR-G-E ... _info.html), though on this site it is not completely clear what specific version of the R5 LED is on offer, color-temperature-wise.

The above seem to compare favorably price/performance-wise to the DX site's Cree XR-E Q5 product, linked to (and extensively experimented with) elsewhere on the board by Daniel (http://www.diybookscanner.org/forum/vie ... 0&start=10). The Q5 is selling on the DX site for $5.09 for 228 lumens at 1A (http://www.dealextreme.com/details.dx/sku.2394). That makes the R5 $1.65 / about a third more money than the Q5 for greater than half more alleged brightness.

Not sure if the "1B" designation on the DX site's XP-G R5, which I am almost certain refers to the 6500-7000k characteristic of the LED, poses a problem for scanning purposes. I think the Q5 has a lower Kelvin temperature profile.

Also not sure if some other characteristics of the R5 LED are relevant. The Cree literature provides tables for all their LEDs regarding chromaticity (seemingly of two types, at least one of which is the above-mentioned Kelvin range), "dominant wavelength," and "forward voltage," whatever those latter two might mean. It's all laid out in an official Cree site page at http://www.cree.com/products/xlamp_xpg.asp and in an official CREE PDF downloadable at http://www.cree.com/products/pdf/XLampXP-G.pdf

The Cree XP-G R5s on both sites are said to have 14mm bases, as opposed to the near 20mm base of the Q5 offered by DX (going by the picture on the DX web site that shows the device in an electronic caliper).

Both the DX and LCK-LED sites seem to be offering the LEDs on Cree bases, or circuit boards, or whatever that quasi-circular thing the LED is mounted on is called. Comments on some of the other DX Cree LED offerings, with bases not imprinted as Cree, complain of lousy quality, specifically solder jobs, giving me the idea that a Cree-imprinted base is a needed feature unless demonstrated otherwise.

The DX site is useful for the comments at the bottom of the some of the product offerings, which are like disorganized FAQs or quasi-discussion boards -- commenters ask questions and answer each other -- by people who are plainly technically adept at both ends. On an odd side note, the Cree LEDs on the DX site seem to be of most interest to people who for some reason are modifying their flashlights. Until someone explains that subculture to me, and perhaps afterward, I am going to have to find it something to chuckle over.

All in all, to a person completely new to LEDs and really to electronics of any kind beyond computer add-in boards and wall light switches, the Cree XP-G R5 sounds like somewhat more brightness for the money with no quality downside. Fellow board members, please correct me if I am missing something here.

[daniel_reetz]

I was rereading the thread and it occured to me to ask how many folks have actually made reasonably effective and relatively inexpensive LED lighting systems for a scanner?

Is there a count of these somewhere? How repeatable is any one design at this point? HELP!! I don't really know how to answer these questions short of reading the whole forum! Does anyone have any idea?

Two people have copied my LED lighting system, and I have built two copies of it. Some people have bought the 10W lighting kits I linked, they seem to work fine.

Hold on for the BuckPuck solution, I think it will be easiest and best.

[StevePoling]

Yaknow, Dan, if you don't have fun manufacturing LED lighting packs, maybe you could "license" the design to someone else with more time than cash to build/sell.

[spamsickle]

I think Dan's designs are "licensed" by default -- if you can build them, you're welcome to build them, either to use yourself or to sell to others. If you can't, ask questions until you can.

[daniel_reetz]

I think Dan's designs are "licensed" by default -- if you can build them, you're welcome to build them, either to use yourself or to sell to others. If you can't, ask questions until you can.

That's exactly right. Every single design I've posted here is free for anyone to use in any way by default. I have no problem with people using my designs to make kits or whatever (though I'd appreciate if people talk to me about selling kits here, just for moderation purposes). The goal here is to get as many people scanning as much as possible as easily as possible.

Now, if someone was awful about it, or they were bad to/a drain on the community, I might change what I do going forward. As of now the info I post here is Free.

[daniel_reetz]

I may start a new thread about this, but my BuckPucks have arrived. I hope to do tests with them this weekend.

buckpuck_DSC0371.jpg (141.4 KiB) Viewed 10310 times

[railman]

How come you always get the good toys to play with. LoL

[ceeann1]

"Where does he get those wonderful toys?" ;-D

We are waiting with great anticipation for your wonderful toys to enlighten us!!

[daniel_reetz]

How come you always get the good toys to play with. LoL

You're the one with the sweet 80/20 scanner.

I've been testing out the BuckPucks. They look like a good solution for most people here, with some small work.

BuckPuck_CIMG0020.jpg (107.21 KiB) Viewed 10287 times

Take some of the DX Cree Q5 LEDs and tin the contacts with solder. Then connect three of them in series. That means from the + of the first one, connect it to the - of the second one. And so on.

solder_CIMG0018.jpg (112.53 KiB) Viewed 10287 times

Connect the BuckPuck's pins to power. V+ goes to + on your power supply or battery, V- goes to negative or ground. There are two more interesting pins on the puck. REF and CTL. REF is a 5V signal. Handy! Handy because if you connect 5V to CTL, CTL turns the LEDS off.

Off.

off_CIMG0021.jpg (121.09 KiB) Viewed 10287 times

On.

on_CIMG0022.jpg (92.96 KiB) Viewed 10287 times

[railman]

That REF pin is just what you need for your arduino. Keep that pin high until you trigger the cameras. Keep the good work going.