help a noob out, pleeaase??

[mixedgas]

[QUOTE=mophead;92726]http://w2s.ledex.com/ledx/ds/lx000/l...sso?pcode=L229

CDRH-FDA approved/

enD quote

Slight correction,
Accepted for use because others have done it, nothing is approved!

Steve

[mixedgas]

(ii) Each laser system classified as a Class IIIb or IV laser product shall incorporate an emission indicator which provides a visible or audible signal during emission of accessible laser radiation in excess of the accessible emission limits of Class I, and sufficiently prior to emission of such radiation to allow appropriate action to avoid exposure to the laser radiation.



I dont get it, how does this work? is that data sent to the shutter? also, is this applicable to lasershows? I need to have a safeguard on galvo speed rather than beam, right? the shutter needs to close if the galvos stop, not if the beam is bright?

The shutter is manually controlled and is wired into a keyswitch on your remote control. They key cannot be removable in the ON position. If the projector is "ON" and powered up or any laser is "ON" and powered up, the emission indicator is on. It is OK and desirable to have the shutter controlled by your software,by placing a relay in the safety loop. The indicator must be designed to be visible through any safety goggles you use with the designed in lasers. I use one red and one green incandescent pilot lamp. It does not have to be blindingly bright. The indicator is for the operator, not the audience.

You must also have a external interlock plug, one of the tests is, if the inspector removes the plug, the shutter must close and no laser light can leave the projector. BTW< they can be anal about stray light scattering off the shutter, block any waste beams.

You design your projector with masking that you can change to protect the audience from stray beams. I use a piece of thin sheet metal that I can get at any hardware store in the US.


my father works at an engineering and mechanical supply company. with one of their products i can measure the signal sent from the controllers to e galvos, and detect whether they stop or move too slowly, and can trigger a signal to the shutter as quickly as 3 or 4 microseconds, its that fast enough? is that sort of scan fail detection required?

also, where can i buy a shutter? would an LCD shutter be suitable? a piece of aluminum on a stepper motor? id anticipate a 3ms maximum response from the unit i built out of a stepper.

NO STEPPER< NO LCD, needs to be a mechanical FAIL SAFE spring return device, ie a dc motor limited in rotation with a spring on it could be considered safe, but you would have to submit drawings of it in the manufacturers report. It is easier to use a device that someone else has successfully varianced in the past, rather then need to have to cycle your home made shutter design 5000 times to prove it works as advertised. LCDs have a contrast ratio of 200 or so, and you need a contrast ratio of "To infinity and beyond".

Hint, dont lock yourself into one part. The language would be something like "XYZ lasers uses positive action spring return shutters such as open loop galvos or actuators with torsion return springs similar to ORCA FOX corp model 666 or Ledex model "clunker 5"or similar comparable parts"

Traditionally you use a arm on the shutter that is black anodized or painted with a carbon black based paint like krylon flat black. The thickness is usually chosen to take a direct hit from hundreds of watts, ie a 1/16th or 1/8 inch thick piece of metal, in front of a hole in a panel so that if the beam is blocked, no scattering makes it to the scanners or arpetures. Keep in mind galvos may not be the only effect you can design in. Pick something that is rated for 100,000 actuations or more in its life, it is damn embariousing to loose a gig because you chose a cheap shutter and cant climb the scaffolding or adjust the projector because it is on a truss over the audience.



A lot of the design practices are tradition based on past known problems, it is easier to approve a copy of a well known device then to design from scratch.

If you use plastic for your case, you might find having to test it and prove that 2-3 times the laser power you variance for wont eat a hole in your case. Yet you could line a plastic case with metal flashing and pass approval for a 20 watt laser.
Your paperwork requires thinking. BTW a common assumption in laser safety is to design for 3-10 times the power you'd expect.
For my lasers, since I use ion, its common to assume the laser power based on what would happen if the power supply failed and dumped the entire line power into the tube and it stayed lit. Unlikely to happen, but....
So you'll see labeling like "2 watts practical limit" for a projector with a 1 watt laser, you use a higher power then you'd ever expect the laser to generate. 2-3 times is a good start, but don't exagerate.


Welcome to professional level safety engineering! Because CDRH is a division of FDA, your making a medical grade device. It could be tougher, you could be designing a Aircraft part.... This is all common sense, but a lot of it is unpublished tradition that you learn by looking at other people's designs.

CDRH will help you if you ask a few good questions and dont waste their time. They will send you a information packet and the forms if you ask.

Now in a seperate thread, we need to discuss how your going to protect yourself finacially and legally. Things like safety and liabilty and how to protect yourself and still get paid if a show fails. Open that thread up elsewhere.

Steve

[mixedgas]

[QUOTE=hibbity;92690](ii) Each laser system classified as a Class IIIb or IV laser product shall incorporate an emission indicator which provides a visible or audible signal during emission of accessible laser radiation in excess of the accessible emission limits of Class I, and sufficiently prior to emission of such radiation to allow appropriate action to avoid exposure to the laser radiation.



I dont get it, how does this work? is that data sent to the shutter? also, is this applicable to lasershows? I need to have a safeguard on galvo speed rather than beam, right? the shutter needs to close if the galvos stop, not if the beam is bright?


my father works at an engineering and mechanical supply company. with one of their products i can measure the signal sent from the controllers to e galvos, and detect whether they stop or move too slowly, and can trigger a signal to the shutter as quickly as 3 or 4 microseconds, its that fast enough? is that sort of scan fail detection required?


Scan fail would be purely optional on your part, as your design and method of operation per your operators manual prevents laser light from going it should where not in the first place.
Ie your laser is mounted on a truss or setting on top of a scaffold, and hopefully bolted down or heavy enough that it does not move with 65,000 watts of BASS shaking it. Don't forget to use high quality lighting grade clamps and a safety cable if you "fly" it.


You do not depend on additional electronics. Your allowed to have a indicator that your shutter is open, and would be encouraged to do so, IF YOU USE NON CONTACT SENSING, but in no case does the safety depend on additional electronics. Its all mechanical, beam stops, actuators, and masking, The box is designed so its simple and reliable and flexible.

Mine has a replacable piece of sheet metal that I would cut at each gig to protect the audience.

Since your dad works in automation, ask him about T-slot tubing or ParFrame for making your projector.

SEE: http://www.thorlabs.com/NewGroupPage...TOKEN=10745532

For a example, although you'll want something other then fiberboard for the sides, and BTW T-slot is available at less cost , but Thorlabs is nice and mills the ends flat. The slots in the inch size tubing are .255 wide or so and common AL plate is .250 thick and heavy black lexan is .220 or .240 See how that works....... Then use some cheap thin AL angle around the baseplate on the inside to make it light tight. Lock in the sides, but you need a removable lid. The lid must have two microswitches or similar in series with the master shutter(s) How you can have a "defeatable" interlock for working on the system is a advanced lesson, or you buy the widget from Microswitch that is standard in the laser industry and can be manually pulled up to defeat it. Remember, that gets a defeatable interlock label if installed.

arpeture labels and warning stickers are the next subject, but I'm outta time for typing, back to the job hunt!

Steve

[hibbity]

The shutter is manually controlled and is wired into a keyswitch on your remote control. They key cannot be removable in the ON position. If the projector is "ON" and powered up or any laser is "ON" and powered up, the emission indicator is on. It is OK and desirable to have the shutter controlled by your software,by placing a relay in the safety loop. The indicator must be designed to be visible through any safety goggles you use with the designed in lasers. I use one red and one green incandescent pilot lamp. It does not have to be blindingly bright. The indicator is for the operator, not the audience.

so i dont need a power meter built into the unit? i thought it needed to be able to display the current output in mw. i was confused.


You must also have a external interlock plug, one of the tests is, if the inspector removes the plug, the shutter must close and no laser light can leave the projector. BTW< they can be anal about stray light scattering off the shutter, block any waste beams.



i dont quite understand the external interlock plug, what is it?

i was considering a dual shutter, one fast regulation shutter, and one that slides across the aperture and fully seals the unit. keeps out dust when the unit is off then


You design your projector with masking that you can change to protect the audience from stray beams. I use a piece of thin sheet metal that I can get at any hardware store in the US.

i was thinking a piece of aluminum with a slot and a wing nut, move it into position and tighten it.


Ie your laser is mounted on a truss or setting on top of a scaffold, and hopefully bolted down or heavy enough that it does not move with 65,000 watts of BASS shaking it. Don't forget to use high quality lighting grade clamps and a safety cable if you "fly" it.

i was going to use a high quality speaker stand with a winch, and bolt or strap the projector to that.


For a example, although you'll want something other then fiberboard for the sides, and BTW T-slot is available at less cost , but Thorlabs is nice and mills the ends flat. The slots in the inch size tubing are .255 wide or so and common AL plate is .250 thick and heavy black lexan is .220 or .240 See how that works....... Then use some cheap thin AL angle around the baseplate on the inside to make it light tight. Lock in the sides, but you need a removable lid. The lid must have two microswitches or similar in series with the master shutter(s) How you can have a "defeatable" interlock for working on the system is a advanced lesson, or you buy the widget from Microswitch that is standard in the laser industry and can be manually pulled up to defeat it. Remember, that gets a defeatable interlock label if installed.

I was going to use aluminum plating for the enclosure. I can probably get my old shop teacher or my girlfriends dad to let me use a manual mill, the funny part is that my girlfriends dad's mill is way better than the schools mill. i was gonna use bent aluminum, or maybe sheetmetal for the corners, inside and out for added stability. if its heavy, ill just out wheels on.

also, do they have to be microswitches? I was planning on building the case in such a way that the beams and aperture were separated form the electronics, do i need an interlock in the electronics part if there isnt any visible light from the beam portion?


the keylocks in the panel covering the beams would break the power circut for the shutter if either was turned, i was thinking that a battery contact spring set to turn away from the contact if the lock is open. to defeat the interlock there will be a switch inside that completes he circuit with the lid contacts open. just a toggle switch from radio shack, maybe doubled so that if i leave the switch on and close the other contacts the shutter closes as well


fot transportation, the mirrors and combiner lenses are going to get all screwed up i suspect, how do i prevent that, ? im going to make nice aluminum plate mounts for everything, will that be sufficient? should i bathe the assemblies in hot-glue to absorb shock?

im thinking about using cat5 cable to give me some distance from the laser, up to 50 yards. i'm anticipating significant difficulties with voltage, and need to look up how that works. just an idea right now.

[buffo]

so i dont need a power meter built into the unit? i thought it needed to be able to display the current output in mw. i was confused.

Nope - no requirement to display output power. Just need to be sure if the CDRH ever decides to check it, your output power better be below the maximums listed on both the warning labels *and* on the variance. That's one reason why Steve mentioned to be sure not to box yourself in. If the projector is designed to make 500 mw of white light, you spec it for 2 watts in case you decide to upgrade the lasers later.

i dont quite understand the external interlock plug, what is it?

Depends on how you have your remote kill switch wired. For sure, if you ever pull the ILDA cable out, the projector should shut down and stay shut down even if you plug the cable back in. Now, if you use the interlock loop in the ILDA cable as your remote kill switch (basically put the switch in line with the cable), then the cable becomes your interlock plug. But some people (including me) have a separate cable running to a remote box with a separate keyswitch, a large kill switch, and a "run" button. If you unplug this cable, the projector stops. If you unplug the ILDA cable, the projector stops. If you hit the kill switch, the projector stops. If you turn off the keyswitch, the projector stops. And in every case, the projector will *not* restart until all the interlock conditions have cleared *and* you press the run button again.

i was considering a dual shutter, one fast regulation shutter, and one that slides across the aperture and fully seals the unit. keeps out dust when the unit is off then

That would be fine, though you'll probably have an AR-coated window on the front that will keep out the dust for you, so the second shutter may not be needed. Be sure you have a way to force the shutter closed on the case (just interrupt the signal from the ILDA connector to the shutter with a switch and it should close).

i was thinking a piece of aluminum with a slot and a wing nut, move it into position and tighten it.

Good idea - just make sure it can't slip...

I was going to use a high quality speaker stand with a winch, and bolt or strap the projector to that.

That's what I use. Make sure it's one hell of a sturdy stand though. Better be able to hold 3X the weight of the projector without moving.

I was going to use aluminum plating for the enclosure. I can probably get my old shop teacher or my girlfriends dad to let me use a manual mill, the funny part is that my girlfriends dad's mill is way better than the schools mill. i was gonna use bent aluminum, or maybe sheetmetal for the corners, inside and out for added stability. if its heavy, ill just out wheels on.

Sounds like a good idea. Your ingenuity will save you money here. Don't make it heavier than it needs to be though. Sheet metal is probably enough for the case. The optical table needs to be thick (at least 1/4 inch, 3/8 or more is better) so it won't bend, but there's no need to use even 1/8 inch plate for the sides, top and bottom. Just adds weight. The channel stuff that Steve suggested makes it easy to work with Aluminum. Check with LJK or Daedal here on PL... They've both used it to build enclosures for their projectors, and the results look great.

also, do they have to be microswitches? I was planning on building the case in such a way that the beams and aperture were separated form the electronics, do i need an interlock in the electronics part if there isnt any visible light from the beam portion?

Are you talking about the case intrusion interlock? If yes, then you can omit these microswitches provided you address it in the variance. You need to explain that you built it, and only you will ever work on it. Thus those case intrusion switches would only be protecting you from yourself. If you state this in the variance, you can forgo the switches. But it's not that hard to add them anyway... (Just put them in series with the rest of the interlock loop. Remember that any break in the loop should kill the projector.)

the keylocks in the panel covering the beams would break the power circut for the shutter if either was turned,

At the very least, it should drop the shutter. Most projectors also kill the lasers on an interlock condition though.

for transportation, the mirrors and combiner lenses are going to get all screwed up i suspect, how do i prevent that, ? im going to make nice aluminum plate mounts for everything, will that be sufficient? should i bathe the assemblies in hot-glue to absorb shock?

No hot glue. It will melt if you leave your projector in your trunk. If you have a stiff optical plate and you mount everything well, you won't have alignment issues. My projector bounces around in the back of my beat up Jeep Grand Cherokee (250,000 miles and still rides like a tank) for 7 hours each way when I go to Florida for FLEM's, and I never have any alignment issues. Just be sure everything is mounted well and you'll be OK.

Adam

[hibbity]

Are you talking about the case intrusion interlock? If yes, then you can omit these microswitches provided you address it in the variance. You need to explain that you built it, and only you will ever work on it. Thus those case intrusion switches would only be protecting you from yourself. If you state this in the variance, you can forgo the switches. But it's not that hard to add them anyway... (Just put them in series with the rest of the interlock loop. Remember that any break in the loop should kill the projector.)

wait, if only i will be servicing the unit, will i need an intrusion interlock? even if my beams are in the same space as my supplies?

i"ll probably add them anyway, but its good to be sure.

At the very least, it should drop the shutter. Most projectors also kill the lasers on an interlock condition though.

I was going to make the shutter a switch and include it in the primary unit power, so if anything trips the shutter, it cuts power to the whole unit. im going to use a push button connected to a battery to prime the unit for ignition, and as a reset. so I push a button to open the shutter with the battery power, hold it, and then switch the unit on, or switch the unit on and push the button to open the shutter and complete the power circuit. once open, the shutter will be powered by the interlock circuit.

I just have to be sure to have extra batteries, just in case. maybe add a rechargeable one or a capacitor.

[buffo]

wait, if only i will be servicing the unit, will i need an intrusion interlock? even if my beams are in the same space as my supplies? i"ll probably add them anyway, but its good to be sure.

As I posted above, you don't *need* a case-intrusion interlock if you are the only one working on the box. You just need to state this in your variance. But it is a good idea to have them anyway.

I was going to make the shutter a switch and include it in the primary unit power, so if anything trips the shutter, it cuts power to the whole unit.

You're confusing terms here. The shutter is an actuator that must block the beam when it's unpowered. You energize it to unblock the beam.

The *INTERLOCK* is a loop of wire (that is, a circuit) which must be carrying current at all times in order for certain other circuits in the projector to work. If at any point along the interlock loop, the current is interrupted, then the circuits that are connected to (or controlled by) the interlock loop will power down. The power to the shutter is one circuit that needs to be shut off, but there are other circuits that you may wish to power down as well.

Have a look at this diagram to see one way to accomplish this.

im going to use a push button connected to a battery to prime the unit for ignition, and as a reset.

No need to use a battery. You still have 110V power coming into the box, which means your main 12V PSU is still powered up. So long as the main keyswitch is on you will have power available to run your interlock circuit. You just use a latching relay to power on the lasers. Again, see the diagram above.

so I push a button to open the shutter with the battery power, hold it, and then switch the unit on,

No. You just need to power the unit on. The shutter will open when your controller tells it to open. Otherwise the shutter stays closed, even when the projector is powered up. The shutter is ENABLED, which means it will open if it receives the open signal from the controller, but it doesn't open all by itself.

I just have to be sure to have extra batteries, just in case. maybe add a rechargeable one or a capacitor.

Forget batteries. You are making it too complicated (and introducing unreliability in the process.) You don't need to eliminate all sources of power in the projector when the interlock is tripped. You just need to make sure that no laser light can exit the projector. In theory all that is required is for you to interrupt the shutter signal from the ILDA connector to your shutter. Then the shutter will close on it's own, and even though the lasers will still be on, the beam will be blocked.

In practice, however, most projector designs also switch off the power to the lasers. This is obviously safer. It's also required in the case of a projector that would need a case intrusion interlock, since in that case if someone other than a qualified technician pulled the back panel off you would want the lasers to shut off to protect them. (Merely dropping the shutter would not help them in that case.)

This is how I have the interlock circuit and remote kill switch wired in my projector. (diagram) As you can see, both keyswitches need to be on before you can start the unit. (One keyswitch is on the projector, and one is on the remote box.) Also, all interlock conditions must be satisfied. (ILDA loop intact, and both scram (kill) switches are closed.) Then you can press one of the run switches (either the one on the projector or the one on the remote box) and it will short around the open contact on the latching relay, pulling it in and starting up the projector. Once the relay closes, current to power the coil flows through the now closed contacts, which will hold the relay in the closed position so you can let go of the run switch.

At this point the lasers are powered on (there is a time delay circuit further on that is not shown) and the shutter signal from the controller is connected to the shutter driver circuit. This doesn't mean that the shutter opens - it just means that the controller is now ABLE to open the shutter when it wants to.

Also, I have a switch in-line on that wire to the shutter driver that must also be closed in order for the shutter to be opened. This is not shown on the diagram either, but it's purpose is to allow you to force the shutter to close (by opening this switch, thus disconnecting the controller signal from the shutter driver) even if the projector is displaying a show. This allows you to warm up the lasers without having any light output from the projector.

If anything breaks the circuit on the interlock loop (one of the key switches opened, one of the scram switches pressed, or the ILDA cable is disconnected,) it will interrupt the current holding the main relay closed. This will open the relay, killing power to the lasers and also disconnecting the shutter signal from the driver circuit, which means the shutter closes.

Also note that even on a momentary interruption of the interlock circuit (the circuit is broken and then immediately re-closed) the main relay will stay off once it is tripped. Even if all the interlock conditions are clear, the projector won't start back up until you push one of the run buttons. This is a safety feature that I strongly recommend.

Adam

[Corporall Clegg]

Well, if you can afford $5000 in lights, you can afford certainly $500 for a professional laser controller and software to run your projector. I know times are hard, especially for someone so young. Believe me when I tell you that *everyone* here is on a budget. But there are a few places where trying to skimp will only hurt you later. This is one of them

Buffo

Is there some secret password or somthing that you use to get this price for an FB3 (if so please share) I called pangolin today 4-23-09 and asked about the FB3 and was quoted $595.00usd I asked about eval or hobby kits as i have heard mentiond in the PL fourms and the price did not change if there is a way i can get an FB3 for 500.00 please tell so i can order it asap

[buffo]

You want to specify that you want the "LA FREAK" kit. This is the FB3 + the LA Studio software, but it doesn't come with the DMX-in daughterboard or a memory card. (At least, it didn't used to come with it - I've heard rumor that this may not be the case anymore.) But the LA FREAK price is $500.

Adam

[LaserLover]

I just completed an E-book titled " RGB Laser Projector Design Guide " which you might find handy If you wish to build your own Laser projector. The link is here along with a free Lumia wheel making instruction offer " http://tinyurl.com/d2lq6v "

Take Care
LaserLover