Im going full out analogue RGB

[stanwax]

thin steel will be ok & you canpaint it or stick black vinyl to it.
As for slide out breadboards - whhooooo posh!

Rob

[Mr.Coffee]

Out of curiosity, have any of you played around with positive pressure case designs? a friend of mine made one for his [video] projector, it has been running for about four years now, and the indside of the case is spotless, the projector good as new.

I'm putting together my own projector right now (buying lasers next week, can't wait!), and was curious if this case style posed a problem for lasers.

in case you guys want illumination as to how this was made, here's brief description of his case.

basically it was a box that sealed fairly well, doesn't have to seal perfectly, because the air pressure inside the box is higher than the pressure outside.
on the side there is a vent cut for the intake of the fans (a couple computer fans in this case), the vent is just a hole, with a Fram air filter stapled over it to pull particulates out of the air. the fans just blow into the case, creating the positive pressure, so no dust/dirt/etc can get in.

I can see that for a laser projector you would need to dissipate a larger amount of heat, but I could see solving that with a basic airflow diagram
(Andy's two level case makes much sense to me, and could be used successfully for staging airflow as well).

Anyway, I just wanted to get some opinions before I dive into putting this beast together.


on a side note, is there a thread for introductions here? haven't said hello formally yet.

[buffo]

I've heard a couple pro's talk about using pressurized nitrogen (or even compressed, filtered breathing air) to manage a slight positive pressure (on the order of a few inches of water) inside the power supplies and heads of their really big guns (monster ion lasers) when doing outdoor events. The idea is to keep the moist air from outside from getting in, because then it can consense on the cooling hoses and cause all sorts of problems.

However, those systems were all water-cooled to start with. So the air (or nitrogen) flow through the system was pretty low. It wasn't there to provide cooling, but just to maintain a low humidity, clean environment inside the equipment.

It sounds like you're thinking about using a set of fans (and some sort of filtering aparatus) to maintain a positive pressure on the projector case while still providing enough air flow to remove the heat generated by all the electronics. While I'm sure that is possible, it's only going to keep things clean as long as the fans are running. When the fans turn off, you loose the positive pressure and stuff can drift in from the vents. (Or were you planning to filter the outlet ports too?)

I think the better idea is to isolate your optics from the rest of the projector (thin sheets of plexiglass held together with aquarium cement would be enough). Then you can have plenty of airflow through the case to keep your electronics cool, while keeping your optics spotless at the same time. Once you've got your optics segregated, if you want to add the filtration on the inlet you can certainly do so, but in any case your optics will stay clean no matter what.

Adam

[Mr.Coffee]

I like the plexi shield Idea, hadn't thought of that, but I can see where it would be very helpful.

as far as airflow and keeping dust out is concerned, my plan was to have a filtered intake at the top back of the case, have the heads and optics on the top section of the case, with a slot just past them for ventilation, then have two exhaust fans blowing out of the case through a louver at the bottom rear of the case. I figured i'd make some cheap one-way vanes so the exhaust fans would blow them up, and when there was no airflow they would fall down to cover the opening.
this wouldn't be an airtight design by any means, but for what I'm building (a low power projector, in the neighborhood of 250-300mw), I feel it should be acceptable, esp. with regular maintenance, and adding other lasers/effects.

[buffo]

Ok, I see what you mean now.

Truthfully, for a low power projector I think it's overkill. But it won't hurt anything, and it might help keep the insides a little bit cleaner. Only thing I'd suggest is to reverse the airflow. Let the hot air out on top and the cool air move in from the bottom. That way natural convection works with your design instead of against it.

Adam

[andy_con]

look what ive got






This 100mw green measures 225mw after about 5 mins



this 10mw blue starts t 40mw and goes up to 125mw after 5 mins




one thing to note about both, the silver psu gets mega hot and mean cant touch it hot.

[allthatwhichis]

Nice andy! I really do like the foot print of the LEs. My 150mW green's power supply always got hot. I just attached mine to the breadbord and it was fine. That's anaother reason I like the CNIs though. The PSUs are sinked and have a fan. Neither my blue nor green I just got, get warm at all. The fans make a little bit of noise but not too much.

When you gonna get them in a good home?

[andy_con]

the foot print is great, nice and small.

i will heat sink the PSU, in the long term when i get my case made both lasers and psu will be on breadboards.

the beam spec on both is amazing. at roughly 16 metres the dots are about 4-6mm. although my blue does have some beam issues, its producing like two small dots next to each other. but when i adjusted the focus it pretty much sorted it.

im in lapland till wednesday and will start building when i get home thursday and fingers crossed in the very very near future i will have a nice metal case

[Banthai]

Hi Andy

I have the Lasever red with this PSU and that also gets hot, Dave from lasershow parts mentioned that these PSUs are only designed to run on a heat sink and told me running without will damage the PSU and diode


all the best ...Karl

[andy_con]

ah i see, ill def mount it on some aluminium then

what red do you have 650nm or 635nm??