Cheap 445

[Stoney3K]

For my laser harp I need some more photons, since it's currently running on a modified ShowTec DPSS. It says 300mW on the module sticker, and we all know you really musn't take that seriously...

Switching to 445nm came to mind, it has plenty of power in a compact package and is (relatively) inexpensive. Since it's going to be used for single axis beam displays on short distances, I don't need any corrective optics. TTL blanking is good enough. And everybody is building green harps these days anyway, so blue is a welcome variety.

In short, all I need is a host, diode and driver ready to go. No bells and whistles, but if you happen to have them it's alright. Guessing $100-200 price range depending on features. (Fleabay O-like is $189 at the moment, so that's my backup option)

If anybody has some stuff around I'm OK with it. Also have some Flexmods left (2 in good, working condition) so I'm also willing to trade or upgrade the Flexmods to 445 modules with some help. Laser diodes and my soldering iron are mortal enemies for some reason.

[hobbybob]

@ the last UKLEM i saw mr. Bowden's nice laserharp in action. Wonderful and he could really play all JMJ songs...
Then they (Rob, Kevski and Mr. Bowden himself) tested in a cool nightclub and took some awesome movies.
What i remember from that is that the harps' sensors didn't work quite as good with blue as they did with green. Maybe something to keep in mind ?

[Carl B]

As Demetri said, you may have problems with the sensor system using a 445 diode. My harp uses 9 LDR's facing down in a overhead cross bar and they were not as happy with 445 blue compered to 532 green. if your using a single up facing photo diode you may be ok. I do agree with you on the colour issue. When my harp was blue, it looked super sexy.

Here' a link to the video Demetri mentioned.
I reverted the harp back to green for the video for better reliability.
http://www.youtube.com/watch?v=mAX781r65QE

I hope you get your harp working with the blue laser.

Carl

[Stoney3K]

As Demetri said, you may have problems with the sensor system using a 445 diode. My harp uses 9 LDR's facing down in a overhead cross bar and they were not as happy with 445 blue compered to 532 green. if your using a single up facing photo diode you may be ok. I do agree with you on the colour issue. When my harp was blue, it looked super sexy.

I hope you get your harp working with the blue laser.

Carl

Don't forget that JMJ used a SP168 argon tube shot through a diffraction grating for the first version of his harp, with a detection mechanism similar to yours. (e.g. LDR's on the bounce mirrors)

For my detection, I already have a set of reliable photodiodes which work even with 50mW of green. They are active in the 400-700nm area, so using some blue should be no problem. I want to use the detection like Albert de Jonge's harp:

http://www.youtube.com/watch?v=xiAofmiSp60

Instead of using a single photodiode/LDR for each string, the entire mirror arrangement is monitored and the strings are detected by extracting the timing. That way I don't need to change the controller on a hardware level if I use an up-facing photodiode (fx. outdoors), just invert the signal polarity.

On most indoor gigs, you need to terminate the beam (or bounce it over the audience) *somewhere*, so it's a good option to abuse that effect.

If blue only doesn't work, I can always shoot it through a dichro and combine it with 445 just for the looks. The cyan from 445+532nm is insanely bright.

[Carl B]

If mixing the 445 with 532 is an option then I would go with that. It would give a real Argon feel to it, like when Jarre did his big outdoor gigs of the 80's and 90's.

Carl

[hobbybob]

Interesting, i am thinking about mixing my sort of 1W greens (one is 800+ and the other is 1200+ mW) with 1W of 445Blue.... Would this work ?
Keep this topic in mind, for a laser harp it would look cool if it could look like the cyan look.

[dnar]

Buy a ticket (or 2 or 3) in the Admin fund raiser. http://www.photonlexicon.com/forums/...ISER-FOR-ADMIN

You might get lucky,

[Geetone]

I would go for an o-like casing+optics (10$ + 8$), a 445nm diode (50$) and a flexmod 3 (40$). That would make an excellent and cheap 445nm module for your needs. You never know when an analog modulation is needed. Even in a harp.
P.S.
Try your luck with helping admin out. :-)

[Stoney3K]

I would go for an o-like casing+optics (10$ + 8$), a 445nm diode (50$) and a flexmod 3 (40$). That would make an excellent and cheap 445nm module for your needs. You never know when an analog modulation is needed. Even in a harp.
P.S.
Try your luck with helping admin out. :-)

I don't really have any problems with getting the parts. Already have a Flexmod and I can probably repurpose an Aixiz housing.

The only problem is that I have a tendency to break laser diodes the second I touch them with any tools! So I want a module ready to go, or someone who can help me bolt it together so I'm certain it works.

As for the Admin-support raffle: I'll probably buy a ticket, but I have a principle against raffles. Lotteries are not my thing, but if it went up for auction you'd catch me in a bidding war. Been there, done that, got the sci-fi convention T-shirt...

@Hobbybob: I once did some experiments with 405nm (Bluray) together with 532nm, and it looked surprisingly well. It didn't really add any brightness, but the colour came closer to the 473nm-488nm range. So if you have any Blurays wandering around, it might be worth giving a shot.