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Messages - dtewksbury
1
« on: December 08, 2009, 05:30:48 pm »
True, but at least in your mind you will see the difference, and you will feel good about it too. 
2
« on: December 08, 2009, 04:20:54 pm »
Yep, I keep forgetting you use sound cards, so you have a signed 16 bit value to play with. I only send 8 bits per color to the FPGA for processing because my hardware is network based and I need to keep the bandwidth to a minimum so that I can control lots of laser heads and other media. Although having said that, a slightly different voltage between 1 of 256 levels would probably not be noticeable anyway I suspect.
I just added color scaling. I was getting sick of the Argon/Krypton looking blue green biased, so I added a scaling adjustment on each color channel. Now I can balance the output for white without adjusting the PCAOM, much easier, and it looks good balanced now, although it is nice to use that really bright yellow line, and the deep violet one.
3
« on: December 08, 2009, 02:54:19 pm »
OK fair enough.
4
« on: December 08, 2009, 06:08:47 am »
Alfa Romeo, I don't mean to be picky, but wouldn't your dichros work better at 45 degrees, or is that photo deceptive.
Just thought they may not be passing as much as they could, or reflecting as much as they should for that matter.
It's just that I have found the angle of incidence seems to have a large effect on the pass bands.
5
« on: December 08, 2009, 02:18:51 am »
mmmmmmm..... That's all cool, but why not just use 256 8 bit values, that's what they will end up in the end anyway.
6
« on: December 08, 2009, 12:41:46 am »
I know what you just said, but I still don't understand the use. Have you divided the color value into 256 of 16384 possible values, then chop off the 8 least significant bits and use the 8 most significant bits from the lookup table to go to the DACs..... Maybe I don't understand at all.
7
« on: December 07, 2009, 09:10:59 pm »
What is it?
8
« on: November 27, 2009, 12:27:54 am »
Cool, I might give one a go just for the sake of it, at least I can then say I have one 
9
« on: November 27, 2009, 12:26:44 am »
Wow, it is 34 Deg C here at the moment, and it will be 40 tomorrow.
10
« on: November 26, 2009, 03:40:15 pm »
Yes I have looked into the class T design and switching methodologies, and don't get me wrong, it's like the rotary engine, really cool. And I do quite a lot of power electronics design, especially switch mode (which I realize these differ from). They are cheap though, and I am interested in the modifications you speak of.
12
« on: November 24, 2009, 10:00:59 pm »
OK well it sounds like this is a common problem. I will investigate further.
13
« on: November 24, 2009, 07:09:44 pm »
I use PCAOMs a lot at work, they are sort of cool, but I find them a bit temperamental, and often don't get near the 80% efficiency they claim. They are probably OK if you just want to modulate one frequency, but it is certainly easier to modulate the supply (assuming the laser likes that).
14
« on: November 24, 2009, 06:34:37 pm »
Yes you should, that is a good price, and all the ones I have have been removed from equipment, and possibly a long time ago, so there condition is unknown. Plus the freight could go over that anyway.
15
« on: November 24, 2009, 06:31:34 pm »
When you say you messed with them, does that mean you took them apart?
This is what I was worried about, I have this laser that has good power, a great beam profile, but just doesn't modulate properly anymore. My worst fear would be that I take it apart and wreck it, that would suck.
Do you think it is OK to take the top off and have a look? I was hoping I could measure the TEC and check that it is working. The reason I think that it isn't is because it doesn't seem to get warm on the outside. I would assume if the TEC was working then it would be pumping heat out, or getting cold if it is heating.....
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