SELEM presentation topics - discussion

[DZ]

and if ONE OF YOU WANTS TO BWITCH ABOUT THE DRAWING FORMAT DONE WHILE PASSING A SMALL KIDNEY STONE AND USING A LAPTOP WITH MS WINDOWS PAIN(T) YOU CAN REDRAWIT YOUR ^%$#ING SELF!

Yeah! No bwitching allowed here!

[mixedgas]

Buffo moaned:
As for using PWM on an AOM; I wasn't aware that they were binary state devices? Thought you could analog modulate with them just like a PCAOM? Clarification please...

Steve Replied:

Many AOs, and Qswitch drivers are just TTL ON/OFF, in fact many PCAOMS have both analog and ttl inputs. mine does. most ones that show up on ebay are TTL input on/off, even though that input is labeled video. The xerox ones are ECL logic on/off, and also labeled "video" on the input. I fear many people have scrapped xerox surplus AO's because of the strance ecl logic levels, on the other hand, ecl works up to a gigahertz or higher,

Steve

[DZ]

Many AOs, and Qswitch drivers are just TTL ON/OFF, in fact many PCAOMS have both analog and ttl inputs. mine does. most ones that show up on ebay are TTL input on/off, even though that input is labeled video. The xerox ones are ECL logic on/off, and also labeled "video" on the input. I fear many people have scrapped xerox surplus AO's because of the strance ecl logic levels, on the other hand, ecl works up to a gigahertz or higher,

I had used a couple Xerox AOM's on a previous projector and they worked great in analog. The ones I used had a video in, but I used the 4-30VDC input to modulate the thing. I ended up selling them to someone on this forum a long time ago, and he put together a page with some information about them: http://24.59.43.169/optics_info/ligh...htshow_rgb.htm

[mixedgas]

I had used a couple Xerox AOM's on a previous projector and they worked great in analog. The ones I used had a video in, but I used the 4-30VDC input to modulate the thing. I ended up selling them to someone on this forum a long time ago, and he put together a page with some information about them: http://24.59.43.169/optics_info/ligh...htshow_rgb.htm

----

I used to change a few resistor values around the ring modulator (silver can on the PCB with 8 legs) and bypass the ECL logic input chip and get analog AM out of them, by passing a current into the diode ring modulator, more current = more RF out to the crystal. I would ground the varactor diode input, the 4-30V you are refering to. What you did with the 4-30 V input changes them into a AOD, acousto optic deflector, because that input is frequency modulating the driver, which changes the output beam angle, not its amplitude. I'd set up a 1K resistor into the ring modulator, so 0-5V is roughly 0-5 mA, and 5 mA turns the modulator full on.

either way works, but the PWM was damn linear to the eye , the AM is more like logrythmic if you plot it out.

Steve

[buffo]

Hey folks! Just got some good news... Patrick Murphy (founding member of Pangolin and current president of ILDA) will be attending SELEM 2008! He will be giving a presentation on the history of the laser show industry (including the back-story behind Pangolin), and he will also be talking about his role with ILDA and the direction that ILDA is moving.

He also said that he'd be able to bring a pair of those holographic "starfield" projectors, like the one he had at FLEM Mark II back in March of this year. (Imagine how cool those will look in the auditorium!)

With the topic ideas we've got above, we've got most of the time allotted now. Of course, there will still be time available for show and tell, and several hours in the evenings will be left for watching laser shows in the main auditorium on both days.

I'm working on a time schedule now, and should have it ready to post in a couple days. Just need to coordinate with the presenters to be sure everything fits.

Thanks to everyone that contributed suggestions!

Adam

[DZ]

Thats awesome, Adam. Glad to hear Patrick is going to make it. Kinda shows that this event is getting bigger, to have another big name added to the list is great. It'd be neat if they could make this event known on the ILDA website.

[buffo]

Hey guys - SELEM is getting close! So I put together a tentative schedule of events. I know that some of the presentations won't take a full hour, and some people may not be attending all presentations anyway, but I wanted to have some sort of idea as to how the days would flow. (Note that lasers can be running in the auditorium while we're doing presentations backstage or in the lobby area.)

Give it a look and see what you think.

Saturday

10:00 - 12:00 Setup, meet & greet, show and tell (equipment)
12:00 - 13:00 Laser Safety : Bill Benner
13:00 - 14:00 Scanner Theory and Tuning : Bill Benner
14:00 - 15:00 History of Lasers & ILDA : Patric Murphy
15:00 - 16:00 Break for lunch
16:00 - 17:00 Practical Optics, Cleaning, and Alignment: Steve Roberts
17:00 - 18:00 Projector Wiring : Bill Benner
18:00 - 22:00 Laser shows in the auditorium

Sunday

10:00 - 11:00 Laser asteroids / Winamp laser visualiser in auditorium
11:00 - 12:00 Laser shows in auditorium
12:00 - 13:00 Laserboy : James Lehman
13:00 - 14:00 LivePro : Bill Benner
14:00 - 15:00 Showtime Live : Hayden Hale (May be canceled...)
15:00 - 17:00 Laser shows in the auditorium
17:00 - 18:30 Pack up and clean up.

[thesk8nmidget]

okay well for us less fortunate people that wont be making SELEM is there ANY way we could record the presentaions!

i would love the oppurtunity to learn a lot more but cant make it this year

[allthatwhichis]

Depending on available bandwidth, we might be able to use ustream again for broadcasting the event live.

[thesk8nmidget]

that would be fantastic!