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Discussion Starter · #1 ·
I'm in a RC flying club. We do a lot of FPV (first person view) flying using a camera and goggles. I would like to have a ground station that everyone no flying can see from the perspective of the pilots.

It has to:
Be bright even during daytime (shade of a tree)
Cheap
Anything over 40 inches

Doesn't have to:
Be HD (our resolution is generally 400x600ish)
16:9 (our aspect ratio is 4:3)
Be good quality. This will just be use for entertainment. We wont actually fly from here so it doesn't have to be that great.

I've been researching and thought a rear projection setup might work but haven't really seen anyone else use one in full daylight. Is this possible? Absolute minimal price for even the poorest quality?

Thanks so much for the help!!!
 

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DIY Granddad (w/help)
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A 50" screen using a $450.00 Veiwsonic PJD5533w, hitting a very dark Grey (...almost Black...) version of Ftoast's screen : http://www.avsforum.com/forum/110-d...asy-ambient-light-rejecting-screen-paint.html

.........painted onto a sheet of Thrifty White Board (@ Home Depot $45.00 total) would give you a whoppin' 244 foot lambert of brightness, figuring the Screen being 0.7 gain. Take it down to 40" diagonal and your getting 379 foot lambert.

Personally, I'd paint up the 50"er and you can always reduce the screen size simply by moving the PJ closer when the surrounding light is really intense.

The first figure would be insanely bright, and the latter would virtually Zerox the image onto the screen surface

So....$500.00 bucks to achieve virtual reality for your hangers-on.


Forget Rear Projection. For it to be effective you would need a Dark Gray material and a Light Box to enclose the PJ to optimize light and block outside light. Bulky, expensive, and wholly not necessary. Far better to construct a simple light shade tent enclosure around or over the Screen. 4 poles and a Tarp. A no brain'er.
 

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Not that I wouldn't be thrilled to see this work out, but I have to ask..for a 40-50" screen, with TVs available for $400 easily (though maybe a bit less portable), would a cheap flatscreen TV be a better choice?
 

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DIY Granddad (w/help)
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Not that I wouldn't be thrilled to see this work out, but I have to ask..for a 40-50" screen, with TVs available for $400 easily (though maybe a bit less portable), would a cheap flatscreen TV be a better choice?
Yeah...but after they come back inside, think about 130" of aerial madness projected onto a wall! :eek:

Sheesh....with a short throw PJ and everyone crowding such a screen to within 5', they would all essentially "be there...doing that".
 

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Discussion Starter · #5 ·
This is great info! Thanks.

A couple of us use small 12 inch or less monitors, but they don't show up well at all in the daylight. Therefore I wouldn't think a flat panel would work all that well. The dark metallic paint looks like a decent option. Before buying the projector I might see if someone has a projector we can try and build the screen. That way if it doesn't work, we're only out $50 for the screen materials.
 

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If you can borrow a projector and are fine risking the amount for a cheap screen, that's one thing, but an area that's so bright it's ruining the picture from an LCD monitor...please don't spend money you can't risk or get anything expensive that can't be easily returned if it doesn't work out.

Light that's bright AND in the direction (from behind you) to cause glare will make the worst trouble for a specialty screen made to reject light too.
 

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Discussion Starter · #7 ·
The light will not be from behind us, so I don't see the screen getting direct sunlight. I plan on building a screen shade to go around the rim of the screen to block out a little more light if needed. Maybe it will be worth getting some sample size paints so I can build a 12" size screen to test. Do they have these kinds of paints in sample sizes? I wont put up big bucks until I know it will work for our application so I will be looking for a projector to borrow. Thanks for the help! If I get this working I'll be sure to post a picture.
 

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DIY Granddad (w/help)
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A sensible plan.

Give Ftoast's Painted Black Screen formula a try. It's neither expensive nor difficult to whip up, and the components are easily available. And...it seems taylor-made for a smaller screen getting walloped by a Uber-Bright PJ.

You shouldn't need all that much gain, considering your screen size of 50" using a very bright short throw PJ. And using a Light Shade....that's a brilliant idea! :p

What is an unknown is if you can really judge things using a borrowed PJ, because unless it has the same properties as what you should / would be using for your application, what you experience might very well be less than what you could really expect. And that might skew your decision making for the worse.

Of course people do have doubts, and some simply cannot decide based solely on the recommendations of others. Also as certain, if someone does spend the time and expense to educate themselves, both assurance and satisfaction usually follows. But just the same, such recommendations that come from peers who have more knowledge in such matters can save both time and expense.

Either way, with some luck...or patience...or goodly doses of both, you'll get there because your goal is most definitely an attainable one.
 

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Discussion Starter · #9 ·
Thanks for the words of encouragement. I do have a couple more questions. You mention short throw projector. Is that referring to the small screen size or short distance to the screen? Can all projectors be used this way or will some not be able to focus that close or zoom to be that small?

I suppose distance from the screen isn't really a big concern since I have plenty of room to back the pj up. However, I would think the smaller I can make the screen size, the brighter the video will be, correct?

I may be asking the wrong crowd since I'm sure most of you are very particular about quality of image, but does anyone have experience with low quality bright projectors? I would assume some 4:3 low res projectors could be found for extremely cheap. I'm thinking sub 200 from china.

I'm thinking this one although I'm not sure 800 lms will do: banggood.com/UC40-Home-HD-800LM-AV-VGA-HDMI-USB-SD-Mini-LED-Projector-p-971531.html

or this but that's getting up there in price and may be worth just getting a well known brand. Also this is LED, is that starting to be common in pjs?: banggood.com/Poner-Saund-Led66-4000-Lumens-3D-HD-Led-Projector-p-947756.html
 

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Oh Lawdy!

Don't even go there!

Now a single one has accurate Lumen specs. Not a one! It's all gobblety **** and Pigeon English....gross Hype that tries to lure in the unlearned looking to score something for almost nothing. Better to buy a used Office Presentation PJ from a shady EBay seller....you'd have a better chance of getting something of value.

No...if you want some decent Image quality (...and you do, really....) in the conditions you'll experience, you will need the real deal.....lot's of Lumen output.

A Short Throw will splash the image you want form under 2' away. That will almost be / will be within the shaded area of your Light tent Awning.
Common sense reasoning tell you that such a position would be far better than tossing lumen output across a distance that competes with other light.

And....a Short Throw will keep the PJ from being underfoot when the Folks all crowd around.

Ya gotta know...at this conjecture, by spending just enough, you can have a really excellent presentation you can be "Suspender-poppin' proud of". Something that can really do those aerial views some justice.

I'm just sayin'......do it right, and do it right the first time. You'll be happiest and most satisfied and never second guess your choice.
 

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A couple random bits of information:

If you have a walmart store nearby, check out their hardware section for a cheap quart of flat paint (get it tinted "Deep Onyx" black, or "Grey Metal" dark-grey) and a quart of Disney/Glidden metallic.
The cheapest tester flats I've found are $3 8oz (homedepot)..a quart at walmart is about $7.
The quart of Disney/Glidden metallic is around $15.

You could potentially use smaller artist acrylics metallic and a tester of flat to mix an even smaller/cheaper amount, but you'd need to find about 8 small tubes of metallic which will still cost around $12 and the flat will probably need 2testers instead of 1.
Even when I'm rolling smaller test panels (ironically about 55inches diagonal) the roller soaks enough paint that having 16+oz of paint per coat is needed..so a full 32oz+ of mix is much safer and maybe $5 more than using testers would be.

I don't recommend a short-throw projector for any of these mixes (short-throw projectors are helpfully marked/sold as "short-throw" or "ultrashort-throw"). I also recommend everyone to ignore any LED projector that claims over 1500lumens or costs less than $350..or comes direct from China.
The brightest cheap LED model you'll find will still cost $300+ and will only output 300-500lumens. The 4000lumen models actually only measure around 100-150lumens, they just lie on the spec-sheet.

There are several $250-350 lamp-based projectors (between 600X800res, 768X1028, and 800X1200), and they easily reach 1000-2000 actual lumens or even more.
You should stick to major brands: Benq, Infocus, Optoma, Viewsonic, Vivitek..that's about it.

If you're borrowing, try to get back to us with the brand and model-name (either on the back or bottom) as soon as you're able.
 

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Huh..guess what, I have a 55" black screen and a 400lumen LED projector..and a sunny day.
If I move the PJ closer and make a 25-30" image, it'll approximate a 1000-1500lumen projector.
It'll be a 1.5parts metallic and 1part flat-black (DeepOnyx) mix.

If you want to use a short-throw, I'd recommend either going with darkgrey 1:1 or a 1part metallic and 2parts flat-black mix at most..that'll help you avoid a bright hotspot.
 

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Discussion Starter · #13 ·
Thanks a ton. I'll stick to name brand stuff. The only reason I even brought it up is because all of our RC electronics come from China.

I don't really need to penny pinch at the cost of being a pain, so I'll just get the smallest easily available size of paints. I assume my application should be between 3 parts metallic 2 parts Deep Onyx to 2:3.
 

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Thanks a ton. I'll stick to name brand stuff. The only reason I even brought it up is because all of our RC electronics come from China.

I don't really need to penny pinch at the cost of being a pain, so I'll just get the smallest easily available size of paints. I assume my application should be between 3 parts metallic 2 parts Deep Onyx to 2:3.
Yes, that's a safe range to stick to with DeepOnyx for a standard-throw projector. Since you'll be painting on two coats eventually anyway, you might want to mix up a half-quart of 2parts metallic+3parts DeepOnyx or 1:1 for the first coat..try it out, then (if you want a little more brightness and light-fighting) use a stronger 1:1 or 3:2 mix for the second coat.


Here are a couple pictures of a 3partsMetallic:2parts flat-DeepOnyx using the 400lumens projector at about 30inches diagonal and about 55inches diagonal.


The sun was almost directly overhead with a thin cloud-cover helping. The BIG help was the lack of bright/reflective surfaces behind me. Even as-is there was enough light at my back to light the screen up slightly brighter than the matte-darkgrey to the right. Typically this screen mix looks darker (with black content) than this matte-grey, but lights coming from behind will get the same gain-boost as the projector.

What's not really shown well is that the black+metallic screen (left side) is visibly "noisier" than the flat-darkgrey (right side)..So that's also a concern. Trading DeepOnyx black for GreyMetal darkgrey would improve the "noise", but give up some contrast for it.

Overall I'd be much more excited over using the projector in a darker room on a large wall or screen than these outdoor results.
 

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DIY Granddad (w/help)
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Last time suggesting: You absolutely need to stick with a Short Throw PJ with 3000 lumen or + if you want total assurance of success.

With that much lumen horsepower, a simple Flay Dark Grey is "all you need" at 50", and the simple Flat Grey will NOT hot spot.

Figure on getting a 1280x 800 resolution model. You can pinch pennies all you want as far as paint is concerned...pinch 'em until they squeak. A Flat Grey is virtually foolproof.

But DO NOT pinch your pennies on the PJ. If it takes $500-600 or so to get what you need in a Short Throw, then do it

...a few suggestions.
BenQ MW621ST

ViewSonic PJD5350LS

Optoma x305ST

Judging from Ftoast's images above, just consider what a Short Throw PJ w/3000 lumen output would deliver on the same Dark Grey.

 

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^^^that's the safer route.
A flat-darkgrey will give a lighter blackfloor and less contrast, but a guaranteed clean image that'll cost practically nothing and requires nothing special to know or use.
A short-throw is more convenient to crowd behind and easier to table-mount in a pinch for a fun movie night later on.

Since the screen sample on the right side of those images is a dark flat-grey and the smaller one is what 1600lumens should look like, a slightly lighter grey might be a better choice.
"Grey Tabby" will be about twice as bright as the darkgrey on the right side of those pictures.
 
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