Planning The GuilleAcoustic design thread

When I read what bulb you will be using, my first thought was "miniature grow room"!

 

fair enough, this is the same type of bulb

 

What I'm thinking about is...

If I'm going to only use a beamer/projector in a dark room, will I even have to use a HQI-lamp, or will something less powerful with alot less heat be sufficient enough allready.

Some energy-saving neon-lights can aswell produce alot of light (lumen) and are very cheap compared to HQI-lamps.

 

good point, definitly worth considering.

 

Nice suggest JRS . I found some nice HID bulbs that are rated for the same lumens, but consume almost 50% less.

If you, or other BTers, are interested, the website is here : http://www.superiorlighting.com/. They are specialized in energy saving bulbs.

Another good link, the Sylvania range (in PDF) : http://www.topbulb.com/find/Catalogs/OS_HID.pdf. They have a huge offer in energy saving HID bulbs.

 

Yeah, I knew there was something better then HQI around, just didn't remember the name of them. Additionally, those Metal-Halide bulbs don't need special sockets etc. Make sure not to grab Sodium-based ones tho because of their yellow light. You want 4000K or above!

The only problem with them is, that they need a few minutes to run at full brightness and they're not ment to switch on and off, etc.

But hey... the price of them is half of what a HQI cost aswell

 

That was a nice dicover, thanks to you mate. I'll try to find a "daylight" bulb, something around 4200K ... not too high or it will be blueish.



I think I'll go with this nice Sylvania bulb (yup, the same Sylvania that made great vacuum tubes)



Model Number: Sylvania 64448 (MS250/HOR)
Lamp Category: Metal Halide
Energy Used: 250 watt
Light Output: 23,000 lumens
Volts: n/a
Bulb Base: Mogul Screw (E39)
Bulb Shape: BT28
Color/Finish: Clear
Average Life: 10,000 hours
Color Temp: (kelvin) 4,200K
Dimensions: 8.35 In. Length

It will give time to prepare some pop-corn then .

I'm very cautious with electronic components.

Yup, I think it's the best option.

EDIT : I found this nice bulb too



Model Number: S4812-SAT
Watts: 70
Lamp Shape: PAR38
Lamp Base: E26/E27 Medium
Lamp Code: CDM70/PAR38/SP/4K
ANSI Ballast Code: M143/M96/O
Finish: Clear
Maximum Length: (MOL) 5 5/16” In.
Kelvin: 4000
Initial Lumens: 42000*
Average Rated Hours: 10000
Pulse Start: Y
Open Rated: Y
CRI: 92
Burning Position: Univ.

It costs more ($76 vs $34) but consumes less power (70W vs 250W) for a more intense light (42K lumens vs 23K lumens). Plus, it has a built-in reflector. The only possible issue is that they need a start pulse circuitery like HQI bulb. What do you think of it ?

 

For those interested in parts, here is a french website that provides all optical parts (except projection objective) :

- Optical miror (mirors that reflect on its surface, no ghost image)
- Fresnel and dual fresnel (OHP)
- Reflector
- Condenser

http://www.fresnels.fr/index.php

 

Goind with the second bulb there could result in an uneven light and shadows in the edges of the image (brighter circle in the middle).

And I was searching the last day for manufacturers of beamers/projectors to get to know what type of bulbs they're using in their beamers. And I got it solved

Professional beamers/projectors use these type of bulbs -> http://www.osram.com/osram_com/Prof...ing/Products/P-VIP_Discharge_Lamps/index.html
It's a pain to find the technical specs of those bulbs, be it Osram, Philips, Sharp or whatever manufacturer, but I found them aswell. They have typically 100-150 Watts and - astonishing! - low 5000-5500 lumens.

So with this knowledge, I'd even try to go with a 150W bulb. As those Metal-Halide bulbs are rather cheap and use a standard socket (E26/E39/etc) the best thing would be to try different bulbs.

 

Even with the condenser lense and the fresnel lense ? I thought fresnel lense where intended to have a uniform light.

Interesting. Knowing that the TFT panel absorb 85/90% of the light ... I thought it would need higher intensity.

I totaly agrea with you. Experiment to have the best suited one ... remaining bulb won't be lost (outside spot, etc.)

 

It might be, that the high-quality optics of professional beamers don't "swallow" that much light, but still... twice the amount should be sufficient, and if you're going to use the beamer for watching movies in a darkened room, then I don't really see a problem there.

The projectors used in school for example are daylight-projectors, intended to be used in a non-darkened room, and that's why they need way more power.

You can do a little research with a torch (would be good to know the lumen of it), a sheet of frosted acrylics (80%) and then a magazine-page (copied onto transparent film) with colour-images.
When enough light of the torch passes through the frosted acrylics to be able and comfortably read and see the magazine-page in 2m distance (projected to a white wall) then you can get an idea of the intensity of light needed in various environments.

This whole DIY-projector stuff is either trial and error with non-standard components, or you simply use the most powerful components to be in the safe side.
The most projects I've seen in the net are all ment to be as powerful as daylight-projectors, which is why they all use 400W HQI-bulbs.

 

Understood ... thanks for the help. I should have spare parts (high intensity bulb, objective and projection screen) lying around at my father-in-law. Next holidays there will be very instructive I think. Time to put my PsP into good use .... lcd cannibalism

Until then, I will experiment the Arduino and the servo-motor I received this week. Time to play a little before I start the real thing (all the motorized stuffs ).

Anyway, a low powered projector would be very nice to me. If it consumes less than a HDTV, then I'll be happy .

Out of the topic, do you have any experience with solar panel ? I'd like to play with those things for small applications.

EDIT : little information about the project I linked a few posts above ... with a 37K lumens 400W HQI and a 1960x1200 15,4" tft .... the guy mesured around 200 ANSI lumens on the projection wall.

 

Didn't choose my name for this post but you are dreaming and is really interesting being able to read about.

i've been like you sometimes, when your brain is just like an outpouring fountain and ideas just flow and overflow one over another.


I'll keep reading; I have, for long time, had in my mind some computer designs similar to your first ones focused in a natural convection cooled computer.

 

Thanks a lot for the compliment. I think that dreaming is important and too many people have since long forgoten about their dreams.

I've long kept all those pouring idea inside my head, trying to keep my head under control. It was really destroying me. Now I let them flow freely and I feel much better. It may seams that nothing is structured, but I'm kinda the knowledge-eater. I truly need to learn new things everyday.

This is the meaning of this thread, a kind of security valve to release some pressure, poping ideas here and there. Maybe some of them will interest other members.

I'd like to thank all the members reading this thread.

 

How about high intesity LED's?

 

I haven't found LED bulb with hundred's of lumens. But if you have some links

 

There's no LED's bright enough for a DIY-beamer. As said, the optics (lens, TFT, mirror, etc) "swallow" some 80+% of the light, so you really need alot of power.

The Power-LEDs, like Cree MC-E (650lm @ 700mA) have alot of power, sure, but these cost aswell €25 a pop. You'd need some 16 of them (4x4 matrix) to get enough light emitted, and this would be very expensive.

Allthough it'd be very tempting to do it with these LEDs

 

It's been done here ... 680 leds panel

http://www.allinbox.com/GohtanBox3/GohtanBox3.htm

 

You don't even need that much LEDs, if you go with HighPower LEDs.

I found modules from Cree (3 LEDs on a little board) with combined 3000lm -> http://www.led-tech.de/en/High-Powe...REE-XM-L-T6-on-round-PCB-LT-1749_120_117.html

They're not even as expensive as the ones I linked there before. Still they'll be more expensive and not as easy to use than the Metal-Halide bulbs.

 

Surely the problem with LED's for an application like this is that they produce a bluish tinged light instead of a more natural white. the spec's on those you linked to there state 5700-6100K which is quite far off the 'ideal' 4200K that the Metal-Halide bulbs produce.

Interesting project this. Certainly something I might have a go at in the near future when I've got a little more money to spend.