Cheap laser for concerts

Hello. I am in a band and want to spice up our live shows a bit. I don't have a lot of money, but would like to get a laser for our shows.

What are the cheapest lasers out there? (multi-channeled, but no need for several colors.) I don't need the best one. Just one that doesn't break too easily and delivers a cool live effect. A cheap laser show is ten times more awesome than no laser show! ;)

Manual or computer based controls are both interesting to me.

I can borrow a smoke machine from my school, so that's all fine.

Thanks a lot in advance! :)

Too many variables...

Where are you located? How large of a venue do you normally play? How many people in the crowd? How much money were you looking to spend? Who will be operating the laser?

You need to know that there are regulations in place that govern commercial laser shows, and depending on which country you live in, they can be quite restrictive. The US is the worst, but some other countries have requirements that are almost as strict. Thus, you can't just buy something off e-bay and start doing shows. (At least not legally.)

Also, it's very rare to have the words "laser" and "cheap" in the same sentence. Nothing about this hobby is ever cheap.

We can help you if you're serious about getting into this, but it's not a trivial exercise.

Adam

Quote:

---

I don't have a lot of money

---

I think it best you quantify this really. As you also mention that you can borow a fogger from the school I suspect you may be young. This may also imply that what you consider not much money might be different to what some of the older people here consider to be not much money.

As far as lasers are concerned, if I was to say £1500 for laser and controller, how would that make you feel?

I don't think he has that much money.
Do you want to make one yourself or do you want to buy a completely built unit?
You can find some on ebay or your local light store but those are mostly crap and unsafe. And yes I'm speaking of experience. I'm still going to school myself so I know $1500 is probably way too much over your budget.
I was caught in the trap of a cheap € 150 unit, very cheap Chinese. It was very unsafe and as it was only 40 mW, the effect got lost sometimes when I put all my other lighting on.
I assume you don't need that much power? Maybe 100 - 150 mW of green is more than enough. Those can easily handle a 500 person venue, with the other lights dimmed. Of course the more power the merrier (and the unsafer), but I saw a gig with 1000/1500 people in the audience and two very small 40 mW lasers on both sides of the stage. I thought "no way those will have any effect" but they had. They were operated by the lighting guy who knew he should dim the other lights when he turned on the lasers.
You can buy a 150 mW green laser for something like €200 (only the laser module) but if you have a bit of luck you can find a second hand unit cheaper.
And I assume you only need a beam show and no graphics? Then 20 kpps (kpps = kilo pps and pps = points per second, the unit of scanner speed) scanners will be sufficient. 10 kpps will also cut it but I won't do that as it is unsafer. (Mine had 5 kpps scanners but don't say that too loud or I will get a lot of replies concerning safety ;-) ) 20 kpps scanners can be bought for under €100 if you know where to look.
For the control of your laser, I think most scanner drivers have DMX input, or come with a separate control board. You can't make your own patterns then. If you want to make your custom shows, you have to buy a dac. Most members here will shout you have to buy a Pangolin FB3 for €400, which is considered "very cheap" here. ;D You can get other dacs cheaper but with less quality.

It's up to you. Ebay premade laser projector: € 300 - 500 and sucking quality.
Make one yourself for € 500 with excellent quality and probably a lot safer.

Quote:

---

Originally Posted by colouredmirrorball

Make one yourself for € 500 with excellent quality and probably a lot safer.

---

LOL, you make me a QUALITY and SAFE laser usable for a band for 500 euro, this will save me a lot of time.

Let me sum up some components and I have chosen some cheap components
Housing 100,-
500mW laser 500,-
Scanfail 150,-
Emergency stop 50,-
laser controller + software 500,-
cabling 100,-
scanset 200,-

hmmm I think i'm already way above your 500 euro.


I think the best thing you can do is RENT a laser from a company who knows what he is doing. then you are safe and cheap.

these guy's aren't telling you the whole deal. i have a lot of experience wome timeithke swhat your trying to do. all you need is a basic 50mw dmx laser and a basic dmx192 or better lighting controller. put the laser at the back of the stage to one side. aim it so that it covers the stage but doesnt hit the crowed.

you still have to check the laws where you live. but trust me, i've put those units on international stages and nobody realized they where the cheap jobs. it helps if you take a bit of time thinking about all the dangers but i've been doing it for ages and the crowed loves it. so do the bands.

dmx is the key. get to know how it works.

As Buffo said too many variables.

If you have less than 30 people crowd and you can dim the ambient lights your solution with a 50mW dmx will work.

no. he's going to get some fog happening. it will do 300 indoors. i have a realy old video where we just dumped one behind the stage without even connecting dmx. i'll try and post a link to it.

http://www.facebook.com/home.php?#/v...id=44304471841

you gotta remember if this guy is playin in a young band he'll be lucky if there's 8 par56's on a four pack. orange gells sound familiar to anybody who actualy does lighting? trust me, one of these and a pair of 75 watt strobes is planty. 1 of these either side is exellent. make's the band look like superstars.. still check legality where you live. there's also a llaw for strobes to. i think 20 seconds at a time max. im not sure though.

Quote:

---

Originally Posted by ondahonda

no. he's going to get some fog happening. it will do 300 indoors. i have a realy old video where we just dumped one behind the stage without even connecting dmx. i'll try and post a link to it.

http://www.facebook.com/home.php?#/v...id=44304471841

---

Excacly, I have watched the video and you laser only looked nice at the podium where the band was playing, but at the time it reached the audience (after 10 meters) the beams were faded out.

Als there was a minimum light in this area

Personally I would find this effect unacceptable for my customers, but thats just my opinion.

This is one of the best picture I could grab from the video:

Quote:

---

Originally Posted by ondahonda

.... i have a realy old video where we just dumped one behind the stage without even connecting dmx. ...

---

Dude !!! :eek:
That's quite sad.

Having a laser randomly throwing out patterns (especially continously, even during breaks between songs) smacks too much of an amateurish way to display a light show.
I realise that this was a cheapo affair but even getting some guy to flick the switch to "Off" between songs would be an improvement (oh, and a bit of haze, smoke).

I guess we all live and learn though and that's why forums like this exist. To offer guidance and advice. ;)

Thanks for great replies! I'm from Norway. To be safe I'll check with the police before I buy any lasers.

Considering what you've said about price, I think I will invest my money in cheaper ways to get a great live show. My budget before our live shows is about 400€. The thought we have is to have a grrrrreat live show for a Muse-cover band project, and establish a good reputation at clubs and good relationship with club owners. That way we can continue having a great live show to our own music.

I think we'll buy/make spotlights with foot-switches for on/off/blinking and make the stage and our outfits very thematic. But it seems that we'll have to wait with the lasers... But one day!! Not too soon!!

I really liked when smoke filled the stage in the facebook-video, but (no offence) it looked odd and unprofessional to have them turned on constantly. If a band member had hired a light guy or had connected the power to a foot-switch, the result would've been much better. I want my band's light show to enhance our music, not just be a fancy effect.

Quote:

---

Originally Posted by Amuse

.... I'm from Norway.

---

Why not check if any members live near you and would be willing to help out at one or two concerts.
That way you'll get for more lasers than you can afford yourself at the moment plus a knowledgable pair of hands at the controls.

Quote:

---

Originally Posted by Amuse

... To be safe I'll check with the police before I buy any lasers.....

---

Good luck with that.
I should imagine an ordinary copper would know less about lasers than you know already. ;)

Quote:

---

Originally Posted by soforene

Why not check if any members live near you and would be willing to help out at one or two concerts.
That way you'll get for more lasers than you can afford yourself at the moment plus a knowledgable pair of hands at the controls.

---

Cruch lives in Norway.

If you're looking for some impact then why not consider strobes with a blinder function or some good old fashioned Molefay blinders? If you look at big stadium/festival gigs that have the wow factor, a lot of the time it's when they hit the crowd blinders. As with any effect, use sparingly, but these should be easy enough to trigger with a footswitch. Have a look at Thomann website, you can pick up 4 cell blinders for about £100 with lamps. You can run these from the Showtec/Botex 4 channel DMX dimmers (about £80) using 1 channel to run a pair of lamps (2 channels unused). If you want to use 2 blinders you'll need 1 dimmer for each. These will give you LOTS of impact within your budget.

I think they may even do blinders with built in dimmers, or smaller 2 lamp blinders.

If you absolutely must have lasers on a gig, hire in someone to do a proper job of it - you'll be much more authentic then with proper beams ;) You could even replicate the Muse show properly then.

Quote:

---

Originally Posted by mccarrot

LOL, you make me a QUALITY and SAFE laser usable for a band for 500 euro, this will save me a lot of time.

---

Where did someone mention quality? ;)
I think 500 mW is a bit too much, say 100 mW - € 200 max
Housing: old computer case - free
DAC: soundcard - € 50?
scan set: cheap 20 kpps - € 100
€ 350 so far... not bad eh?
About scanfail and safety and the like... a lot of people don't have the money for it. Simply avoid audience scanning is a cheaper option.
I don't know what you call usable but I think some DMX laser effects above the audience are far more better than no lasers.

But if you really want a nice show for that one special night... hire it.

Its a band, they will use it as it was some kind of Par and they need to take it every week to a location. A laser in a computer case will not even last 3 shows. then its gone 350 euro.

You need a strong case and a flightcase.

Also a souncard dac is not usable with audiance.

a FB3 with the Muse show stored in the memory they can start with a very simple DMX panel would be nice.

Quote:

---

Originally Posted by mccarrot

Also a souncard dac is not usable with audiance.

---

Umm, how so?

Now it is not something I would be likely to do (Except as a get out of trouble fix), but not usable is a bit strong....

The DAC should NOT IMHO be involved in any way in audience safety (possibly beyond completing the projector interlock loop (Which should not itself be AUDIENCE safety critical), so it is not a safety critical component in the sense that a scan fail board is.

My firmly held view is that audience safety is ideally a function of black wrap, multiple stop down filters and mechanical beam blocks, not software that was not written and tested to SIL4 (And nobody writes laser show software to SIL4, because SIL4 is a nightmare).

Regards, Dan.

Can you assure for 100% the souncarddac wil NEVER put out a (unwanted) static beam in any case?

If your answer is no you cannot use it with audience in my opinion.

Quote:

---

Originally Posted by mccarrot

Can you assure for 100% the souncarddac wil NEVER put out a (unwanted) static beam in any case?

---

That is exactly my point, you cannot really say that about ANY DAC, the safety systems have to work irrespective of what comes down the ILDA cable.

If the projector is set up with hard masking so that a beam cannot ever go into the audience at unsafe power levels (even if it is static) then irrespective of whatever is being used as a DAC it is safe, same thing if there is scan fail hardware setup correctly, otherwise you have to assume that you could end up with a static beam in the crowd.

For very similar reasons I have issues with software controlled intensity maps as a means of keeping crowd scanning below MPE limits, what happens if the feedback resistor in the DAC output stage goes open?

What happens of someone puts a stilletto heel through the ILDA cable and manages to short X+,- and Y+,- to ground?

The DAC is far too far up the chain to make it a practical part of the safety systems.

Regards, Dan.

Quote:

---

Originally Posted by Amuse

Thanks for great replies! I'm from Norway. To be safe I'll check with the police before I buy any lasers.

---

Police have no ideas what you are talking about. Most of them anyway! Class 4 lasers, you need to fill out an form and registred at Statens Strålevern and get it aproved! You can use class 3b lasere here without any problems, so long it is a safe setup. No audience scanning, witout all saftey requirements..

And I do have some lasers equipment for sale..and I am from Norway! :D

Quote:

---

Originally Posted by mccarrot

Can you assure for 100% the souncarddac wil NEVER put out a (unwanted) static beam in any case?

If your answer is no you cannot use it with audience in my opinion.

---

thats a pretty silly statement... you cant guarantee a QM2000 will NEVER put out an unwanted static beam either... what if the driver crashes in some magical way? or you get a power surge that freaks out the card or some totally implausible yet possible event... scanfail should be in the projector, and you should have interlocks and a big red "holy crap" button... while a soundcard based dac does seem a lot scarier than other options, I really cant see how it would be THAT much more plausible for it to fail in the manner you describe

It's not silly at all...

The QM-2000 has been designed from the ground up with laser safety in mind. Every circuit is designed to fail "safe". True, this does not mean that some crazy confluence of power spikes, driver errors, and acts of god could not cause it to emit a static beam, but it's damn unlikely. Pangolin understands that their device is an important link in the chain of laser safety, and they spend a *lot* of time making sure they get it right.

Contrast that with the design of a cheap USB sound card. It's not a critical safety device. Not at all! When used as it's intended (driving a set of headphones), there is very little - if any - risk in the case of a device failure. Thus there is no need to design a sound card to fail safely. Likewise, the drivers for these cheap sound cards are notoriously unreliable. Several users (including me) have experienced system crashes (under Win XP pro) while running these devices. And that's not a big deal if you're using it just as a sound card.

But when you modify it so it will drive a laser projector, you just promoted that device to "safety critical" status. Now it *is* important that the device not fail improperly. But have you done anything to the sound card (or the drivers) to increase it's safety or reliability? No, you haven't. And that is exactly what Mccarrot is talking about.

Yes, there is always operator intervention to consider. But human reaction times are not instant, which is why a proper laser professional does everything he can to prevent problems before the show is ever put on. You don't just slap some gear together and then say "well, if anything goes wrong, I'll just hit the kill switch..." Try putting that in your variance and see what the CDRH has to say about it...

To imply that a sound card is even remotely secure compared to the QM-2000 is laughable. One is a professional device, the other costs $20 on E-bay and is disposable. While I agree that a sound card makes a great first controller for a hobbyist on a very tight budget, if you're doing professional shows you can afford a professional controller (be it one from Pangolin or another manufacturer).

Adam

Not disagreeing with your assertion that a real DAC is a superior answer (or that a manual scram switch is going to be far too slow if a static beam is hitting someones eye (seconds, you want well sub ms shutdown if it goes pearshaped that way), but I do take issue with the DAC being part of the safety system.

The DAC even if it is effectively standalone with on board processing (QM2K style) which was written to a suitable safety integrity level (most are not, and you cannot rely on a PC driver for this because Windows is both far from a realtime system, and is certainally not qualified for use in a safety critical system) is still at the far end of a (usually) cheap off the shelf printer extension cable, and is thus too remote from the action.

Safety critical systems should be designed to minimise the complexity of the parts within the safety critical area, in this case you do this my arranging for the projector to be safe for the audience irrespective of what is fed to it, not by designing it so that it is safe if it is not fed anything silly!

The 'failiure surface' that you have to be concerned about rises extremely quickly once you bring software or firmware into the picture and designing a hardware and software system that is known to fail safe (even in the presence of say a VHF walkie talkie coupling to a cable that is just the wrong length[1]), really is rocket science. The limits of formal verification (even abscent processor manufacturer errata notices[2], and even assuming the assembler and liker have no bugs[3]) are only a few thousand lines of code.

If ADAT (which has some truely nasty failure modes) is good enough then it surely follows that a soundcard is no worse (Provided you buy a good one)?

Regards, Dan.

[1] This has actually caused serious problems with theatrical scenic automation at theme parks and major venues, where the computers are in some cases running multi hundred HP drives, or motors flying people! The saving grace is that the safety systems do NOT involve the computer (except possibly as a status display).
[2] For example the HC12 had a doozy where every 4096th time it woke up from sleep on interrupt, it kind of didnt! An Intel Core 2 has 88 pages of erata last time I looked.
[3] A certain embedded vendor has a compiler that I discovered forgot what "volatile" meant when you turned the optimer on, nightmare!

ADAT's aren't used for any audience scanning shows that I'm aware of. Controllers are, and that's why they need to be part of the safety loop. (In a non-audience-scanning show, typically a projector mask is used to eliminate the possibility of beams reaching the crowd.)

Coupling from an errant VHF radio to a laser projector's output would be impressive, since the X & Y position data is resolved using a differential receiver on the scanner amp inputs. You'd need one hell of a coincidence to couple to just one leg (on each amp) and not the other to create a static beam that way. Still, if you are running single-ended receivers on your galvo amps then I could see where this might happen. But it's still highly unlikely. (And it's just about impossible with differential receivers.)

As for cable failures, that is addressed in the ILDA pinout. (Re: the interlock loop). If the cable fails, the projector quits. Granted, you could have a failure of a single wire inside the cable, but that's awfully rare, and in any case that would collapse only one axis (X or Y), so that still wouldn't yield a static beam. In my personal experience I've never had a cable failure, but I do buy decent cables, and I store them carefully.

I agree that hard projector masking is the way to go for non-audience scanning shows, and in fact this is the way it's done here in the US. But since audience scanning is far more prevalent in Europe, you can't use a mask to keep the beams out of the crowd... True, you should also have a scan-fail interlock if you're going to crowd-scan, but having a reliable controller is also important.

I agree that the controller is not the *only* safety critical device in the system, but I do believe it is prudent to consider all components (including the controller) when assessing the safety of the show.

Adam

Quote:

---

Originally Posted by buffo

Coupling from an errant VHF radio to a laser projector's output would be impressive, since the X & Y position data is resolved using a differential receiver on the scanner amp inputs. You'd need one hell of a coincidence to couple to just one leg (on each amp) and not the other to create a static beam that way.

---

Just how much gain bandwidth do the opamps you are using have? CMRR at > 5 MHz is mostly non existent with a simple 4 resistor and opamp style diff amp, and not that much better even if you get clever (And besides, I see an awful lot of 'ILDA' cables that are NOT twisted pairs).
The real fix is common mode chokes, but I don't see much including them.
Actually, the place where this really tends to bite is when the RF gets picked up by something like a clock trace on a processor card, instant crash, and it can be a right monkey to find (BTDT).

The other thing that hurts us here is the tendency of a lot of builders to NOT connect the screen directly to chassis at the projector, AES 48 has much to say about this from an interference rejection perspective. See also papers by Neil Muncy, Bill Whitlock and Tony Waldron (they are written for audio, but we have many of the same issues). Basically not doing this makes the screen a NICE aerial for AM radio, and if the kit at the other end ties it to signal reference rather then case ground......

Quote:

---

As for cable failures, that is addressed in the ILDA pinout. (Re: the interlock loop). If the cable fails, the projector quits.

---

Hopefully! Designing an interlock circuit which actually works really reliably is not as trivial as it appears on first glance, and the tendency of a lot of kit to have badly thought out ilda loop through connections does not help.

Quote:

---

but I do buy decent cables, and I store them carefully.

---

That does of course help :-)

Quote:

---

True, you should also have a scan-fail interlock if you're going to crowd-scan, but having a reliable controller is also important.

---

Well yea, but I tent to put the controller in the 'Production Critical' rather then 'Safety Critica'l class, the rig should be safe (even if the show is lost) irrespective of what the controller outputs (and in fact, irrespective of what the projector receives).

One approach I have seen used to dim things when crowd scanning involved a set of 2 stopdown glass sheets that could be set in front of the aperture to attenuate the beam power when the Y axis dropped below a suitable point. A sort of mechanical intensity map. Combined with a scan fail, all is good.

Regards, Dan.

Quote:

---

Originally Posted by buffo

It's not silly at all...

The QM-2000 has been designed from the ground up with laser safety in mind. Every circuit is designed to fail "safe". True, this does not mean that some crazy confluence of power spikes, driver errors, and acts of god could not cause it to emit a static beam, but it's damn unlikely. Pangolin understands that their device is an important link in the chain of laser safety, and they spend a *lot* of time making sure they get it right.

Contrast that with the design of a cheap USB sound card. It's not a critical safety device. Not at all! When used as it's intended (driving a set of headphones), there is very little - if any - risk in the case of a device failure. Thus there is no need to design a sound card to fail safely. Likewise, the drivers for these cheap sound cards are notoriously unreliable. Several users (including me) have experienced system crashes (under Win XP pro) while running these devices. And that's not a big deal if you're using it just as a sound card.

But when you modify it so it will drive a laser projector, you just promoted that device to "safety critical" status. Now it *is* important that the device not fail improperly. But have you done anything to the sound card (or the drivers) to increase it's safety or reliability? No, you haven't. And that is exactly what Mccarrot is talking about.

Yes, there is always operator intervention to consider. But human reaction times are not instant, which is why a proper laser professional does everything he can to prevent problems before the show is ever put on. You don't just slap some gear together and then say "well, if anything goes wrong, I'll just hit the kill switch..." Try putting that in your variance and see what the CDRH has to say about it...

To imply that a sound card is even remotely secure compared to the QM-2000 is laughable. One is a professional device, the other costs $20 on E-bay and is disposable. While I agree that a sound card makes a great first controller for a hobbyist on a very tight budget, if you're doing professional shows you can afford a professional controller (be it one from Pangolin or another manufacturer).

Adam

---

I was not disagreeing with you, im just saying no device is always going to fail safely, and no safety device is going to be better than a well trained vigilant operator... when it comes to critical electronic devices shit happens, especially when its least convenient cause thats just the way it works lol

that being said, I would not audience scan with a sound card dac personally, and would imagine anyone that is well versed enough to think they can audience scan safely would also realize that would be a poor decision ;)

Quote:

---

Originally Posted by DMills

Designing an interlock circuit which actually works really reliably is not as trivial as it appears on first glance

---

You think so? This is what I came up with on my first attempt. It seemed pretty trivial for me, and I'm not an EE...

http://www.photonlexicon.com/gallery...+Schematic.gif

Quote:

---

Originally Posted by ondahonda

no. he's going to get some fog happening. it will do 300 indoors. i have a realy old video where we just dumped one behind the stage without even connecting dmx. i'll try and post a link to it.

http://www.facebook.com/home.php?#/v...id=44304471841

---

what mw laser are you using in the video? thanks and God bless.