Crazy, but true!!

[Things]

OK, this may seem like I am joking, but my school wants a laser projector

Basically, they have a large hall, which is out near a road, and had an idea they would like to project some things like text on there when they have events etc.

So, the laser would be on the ground, covered by a metal waterproof box. The box would have air holes. They were considering running a cable to a room, for the control, and having a dedicated laptop. However, I dont think they realize what kind of cable they need, so I was thinking, have a FB3 built into the laser, and have a sealed USB port on the laser, so if they wanted to change it, they just take a laptop down, type it in and set it to auto cue. That way, they can put the laser on a timer to come on every night and not have to worry about software.

They did say they wanted an RGB, but considering what they want to scan, I think their budget won't stretch that far, so I am thinking a high power green.

However, since the laser will be mounted on the ground, and will need to project on a huge building, it will need to have a fairly good sized scan angle, and speed since they want scrolling text.

How much is the Kvant 1W RGB ("Spectrum") I think it's called? The building is dark purple and dark green, so I think a >500mW green would be more within their budget and visually brighter.

So basically, I need some recommendations on some scanners, a laser and just any other advice.

I think they would still love green, but I dont think they have the budget for RGB of significant power.

Just ask if you need any more info

Cheers,
Dan

[soforene]

I should imagine "Ground Height" just won't cut it cus some poor little darling will go and stick their eyeball up close to see what it feels like.

[Things]

It will only be on at night, no need to worry about that

The school is completely fenced and locked at night, if they still somehow get in and stick their eye into it, well that's their fault

[soforene]

Ahhhh... Didn't realise that you ozzies have a curfew for stoopid people.
What an enlightened country.

[Soulstorm]

My laser gets it's ILDA signal via a CAT5 cable with RJ45 connection. That is something you could keep in mind if you wish to run it on the fly.

Moisture will have to be considered also... hehehe. And bugs... outdoor permanent mount might be a pain. What about mounting inside by a window?

[Things]

Well the box can be sealed, however I didn't think about the humidity issue. And yes, I was thinking cat5, but at the length we'd need it wouldn't be very cheap. Bugs arent a problem, it will have air filters and mesh over the air holes to prevent that.

Maybe I could load the box up with silica gel?

But there is no other buildings infront of it. There may be a possibility it could be mounted on a post, but then lightning, wind etc becomes a problem.

EDIT: Our weather extreme's are: Lots of rain in the summer, cyclones, high humidity and some hot days. No cold temp's, ice frost etc to worry about.

[Things]

OK, I have run up a few prices. Looks like $2800AUD would cover the entire build fine.

DT40's from LSP
300mW LW greenie from LSP (Higher power depending on how much they can spend)
FB3 from Pango
Random hardware/screws/baseplate/scanfail/safety features etc. I would leave a little lee-way of course, but it entirely depends on their budget.

I have a few prices now, so I will see what they can do

This thing has to be kid proof, and not in danger of blindness ways, but more from things like being kicked, food shoved into/sat on etc

So I am thinking, build the laser into it's own case, over that, have a bulky metal case bolted to the ground (concrete platform), and if possible, even a fence around it.

For the front window, is there such thing as AR coated perspex? We don't get hail or anything like that here, but like I said, kids.

[gogu]

humidity will damage your mirrors with time (seen this on a few projectors) Would a sealed projector with components heat sinked on a cooling channel that draws air through?

[Things]

That is an idea, and I was thinking maybe even the surface area of the protective metal box would be sufficient. How are the DT40's in regards to heat?

[White-Light]

I should imagine "Ground Height" just won't cut it cus some poor little darling will go and stick their eyeball up close to see what it feels like.

Yeah I would have thought a pole mounted solution would have been better - much easier to justify the fact that you took into account the safety precautions if anything goes wrong. Also, easier to defend from the onslaught of kiddies - a barbed wire and steal collar below the box should prevent both easy access and accidents through scaling the pole (or anti climbing paint if you're worried about claims from wire injuries). So long as you have a small scaffold or large platform step ladder, you should be able to get service access (I suggest making the projector removable from the external casing for this reason as its easier to work on it at ground level).

Would also potentially project better as no angles involved if projector was mounted centrally opposite the area to be projected onto.

My own personal opinion, is your risking law suits if ground mounted even with precautions as its foreseeable that kids will break rules and enter areas they're not supposed to and the onus is going to be on you to show that you took into account all of these factors and made adequate precautions against them. The mere fact that kiddie got access is in itself going to raise questions of the adequacy of your precautions, better to take a belt and braces approach from the start. Much easier to justify yourself if the kiddie had to scale a pole, ignoring warning signs on the way and then overcome further anti climbing protection to expose themselves.