LASER show for my Church

[chuck]

I'm having fun this year, preparing for Vacation Bible School at my Church. We're doing a circus theme, and I think I can make the LASER show I've wanted to do, work for this theme.

Basically I've built a simple spirograph projector, using surplus optics and PC case fans. Simplicity itself -- love the design.

BUT, my question has to do with power levels. I know I can get a pointer of any power on eBay, and have even found ones of 10-50mw output for a total cost of around $40. This is definitely within my budget. Do I need to worry if I use one of this power? I don't want to skimp on the brightness, but I know 5mw is the legal limit in the US. (Texas)

The show will be indoors and in a semi-darkened church...but still reasonably well lit. I have the option fo doing either front or rear projection, since I'm putting up a gauze-y fabric to imply a circus tent.

Anything I need to know, before I start bidding on green pointers?


THANKS!

-- Chuck Knight

 

[Jason1]

To be honest in that power range, I wouldn't be too worried, IR will not be a problem if you are projecting into a large space, and 50mw of green should be no problem if you intend to scan using your spirograph scanner, and especially if you are scanning into a material surface.

Get the most mw you can afford in your budget :goodjob:

Jason.

 

[Kwizatz Haderach]

A big question is how long untill you have to be ready with the laser show. If I was going for a laser on the cheap I would get a Dealextreme 30mW most likely for $32 includes shipping. The only problem is it can take up to a month to arrive(mine took 20 days).

I run mine off Energizer Lithium E2's but only lase for no more than 10 seconds at a time or so. If I were to run longer I would most likely use NiMH batteries which would have a lower voltage and let the diode run cooler. Albeit the output of the laser would drop. I think the E2's higher voltage would drive the diode too hard if used over several minutes due to the minimal heatsinking used in a "pen style" laser.

The only thing to worry about is paying for a 50mW on Ebay and getting a 3mW or so or one that has really bad beam specs. It depends on your level or risk. I'm usually a risk-adverse person so I probably tend to be over-cautious. There is a good chance you will get a good laser however and $40 is'nt a huge gamble anyway.

As far as the legality of <5 mW I thought I read that it can be over that if the scanned beam is less than that(example: a moving beam and not a point source). You could also buy an inexpensive Neutral Density filter from a camera place and place it just after it exits the mirrors.

Curious if anyone has more legal knowledge on this and wants to chime in.

Kwiz.

 

[The_LED_Museum]

If you operate a laser show in public that uses a laser greater than 5mW, you'll want to have a beamstop (ledge) at the lower front of your projector to be absolutely, positively, 100% certain that people cannot access the laser beam if your scanner fails.

 

[chuck]

If you operate a laser show in public that uses a laser greater than 5mW, you'll want to have a beamstop (ledge) at the lower front of your projector

Not a problem. I was going to place it behind the baptismal (we immerse, so it's the size of a large hot tub) and use that as a failsafe. I'll be aiming it upwards, anyway, but that should keep it out of the reach of little hands and eyes. I don't expect problems...but then, you never *expect* them, do you?

A big question is how long untill you have to be ready with the laser show. If I was going for a laser on the cheap I would get a Dealextreme 30mW most likely for $32 includes shipping. The only problem is it can take up to a month to arrive(mine took 20 days).

End of the summer...end of July. I have plenty of time, and that's why I can afford to be ambitious with my plans.

Where does one get these dealextreme lasers?

And, these are the two LASERs I've been looking at. Remember -- Church budget, so cost does matter. I'm willing to chip in some extra money if it gets me materially better results, though.

I checked at Fry's Electronics and a green pointer is WAAAAY out of my budget for this project. eBay to the rescue, I hope. Each of these comes to between $20 and $40, shipped. *That* price, I can justify. In fact, I'll probably just pay for it myself, so that I can have it to play with, after VBS.

-- Chuck Knight

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=005&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=150116553873&rd=1&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=018&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=280109001687&rd=1&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=018&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=280109005563&rd=1&rd=1

 

[chuck]

The only thing to worry about is paying for a 50mW on Ebay and getting a 3mW or so or one that has really bad beam specs.

Just for reference, I've been picking up red pointers at the dollar store, and playing with them. That's why I want to go brighter...<1mw just fades out when scanned, even in a dimly lit room.

Remember, this is for children (and my preacher) who will be wowed at the very thought of having a LASER show of any sort. Keep it simple is my mantra for this year...next year, I may try to build a fogscreen.

-- Chuck Knight

 

[Kenom]

I got a leadlight from ebay from a user named vital*spirit He sells his lasers for a very modest price or a bit on the spendy side if you go with the buy it now option of $55 shipped. This is a simple 5mw green laser. You can do a simple modification to the potentiometer to increase the output power on it to upwards to 50mw if you get a good one. One downside is if your not careful you can ruin the laser and make it unusable. However it's a Good project laser to start with as is the laser on www.dealextreme.com. You do have to remember that anything over 5mw is illegal in the us so buying anything on dealextreme you run a potential for having it taken by customs. the leadlight is very bright just at a default 5mw as green is more visible to the human eye than red by a long shot. so even in a dimly lit room green 5mw is going to be at least 5x brighter than a 5mw red laser.

 

[luvlasers]

Basically I've built a simple spirograph projector, using surplus optics and PC case fans. Simplicity itself -- love the design.-- Chuck Knight

Any chance of posting a few pics of your design, keen to see how you have put things together. You might inspire me.