Hello, can i use this soup ladle's head as a reflector with my bulb ? ( i mean is it effective)?
I just bought the 400 watt osram MH bulb yesterday and i hooked it up to the ballast, ignitor and bulb holder that i bought and it worked.

Hmmm, seems you moved from halogen to this MH bulb, good choice. I'd say any reflector is better than no reflector especially if it's (ladle) spherical. Can you post a pic of the ladle on it's side and with the bulb next to it to see size comparison and shape? BTW, I beleive the LL's pro-reflector are now in stock at the store and they will out perform your ladle.

Hello, this is a pic to cmpare sizes between the ladle (reflector) and bulb. And this is a picture of what is going to be my light box. I am going to fit the bulb in it and screw the soup ladle's head to it so it would reflect more light.

Size comparison looks good, can't tell from the pic if the ladle is spherical or has a flat bottom. I don't recommend fully containing the light engine in your tube but rather have some ventilation for heat to escape and drawn out of your projector. Depending on the quality of your stainless steel ladle (if it is) MAY tarnish to a golden brown over time from being close to a 400w lamp.

hello, then can i use this?. its a reflector for a 300 watt halogen and i can fill the empty spaces with aluminum foil i think. And i am also having a problem in connecting my computer fan. I connected it to a 12v transformer and it didn't work i stripped the black and red wire then i onnected them to the transformer. here's a pic.

No. That reflector is intended to diffuse the light, which is the opposite of what we want.

The ladle looks better, but the LL pro reflector is better yet.

My tests:

Stainless steel (ladle) polished to excellent reflecivity yielded 125% Lux value of lamp with no reflector.

LL Pro reflector yielded 150% of lux value relative to lamp with no reflector.

I guess i am going to use the soup ladle as a reflector. Inside my own light box if u see the other reply. I also made myself two fans by connecting them to the USB port on my laptop (stripped the black and red wires and it worked. Are the fans now good enough to make air circulate in the box.

That all depends on how much cubic feet of air flow the fans are rated for. Mind you that you want to pull air into the box through a open vent then pass it between the fresnel and lcd then hopefully pass near the lamp and then draw it out the box. In other words, in with the good air and out with the bad. I hope I didn't misinterpret your post and that you have read up on the basics of building, if not please let us know.

Hello, thank you for the reply, i think i am going to use the fans because i compared it to the one that is connected to the motherboard in my computer case and it has a very slight differnece in speed between the one i connected to my USB port. I am only going to have three fans or two. the two are going to circulate air between the lcd and fresnel. now i am in the phase of making a frame/mount for my LCD and fresnels. I ordered my fresnels on september 3rd and i think they are going to arrive at september 10th or 11th. Ae there any ideas for making a mount or frame?

There are tons of ways to make a decent frame, and many different materials which work well. I used the frame material that's used for screen windows for mine, but with the slot turned inwards, and the corners made with "L" brackets. It worked well for me, and keeps the fresnels flat.

You can just cut grooves into wood with a tablesaw as well. Probably simpler, but my tablesaw is a thousand or so kilometers from my home, so it wasn't exactly convenient to pop over to zip a couple of pieces through...

One thing that you SHOULD do, however, is leave a couple of mm for heat expansion. The fresnels will get warm, and they will expand. If you leave a bit of room, then things will stay flat easier.

Thank you for the reply, I think i am going to go with the tablesaw one. Thank you

I am currently going to use a collimator lens that has a 220 mm focal length s15 fresnel but i lose half an inch from the left and right sides of my LCD but my other fresnel (collecter) 330 focal length 320x400mm is as big as my screen) I just ordered it will the projected screen project the screen with the half inch from both sides gone or will it project the full lcd? i am using a 15 inch widescreen flatron lcd from LG.

You can only project when you have light that leaves the LCD panel and hits the projection lens. If your collimator lens doesn't cover the last 1/2" from the edges, then that area will be dark on your projected screen.

so, it will be darker but it will show?. another question. will a 330/550 combination work ? 330 is collimator and 550 is field fresnel with a 330 triplet.

It'll show but in very distinct different shades of brightness. You can use 2 of the 330 fresnels for collimating and collecting they will work.

thank you for the reply. Do you think i should put switches for my lamp/lcd/fans?. You think i should put seperate switches for each one ?.

Yes, switches are good. Generally, I don't worry about a separate switch for each thing, for example, I can't think of a situation where I would want the fans on, but not the LCD, for instance. Nor would I want only SOME of the fans on, so I'd just use a single switch for all of that stuff.

There's a sample wiring diagram which works well. I think it's in the Beginner's area. Hmmm. Been here too long, I can't remember where I put stuff.

ok, i found the diagram but i think i will have to seperate the fans from the lcd and lamp because my 3 that i just made get power via USB. BTW u are there any good places for where i could put my 3 fans?. i think that i will put two between the rear fresnel (one sucking and one blowing) and i don't know where i will put the 3rd one maybe i can put it between my rear fresnel and tempered glass. Got any ideas?



BTW:thanks for all the fast replies

I use a 12VDC adapter for my fans in my pro lens build, but just for arguments sake, there also exist plug in modules which provide 5VDC and have a USB A socket on them.

I would STRONGLY suggest that you NOT make your fans dependant on a running computer. After all, if someone shuts down the computer and that lamp is still on, you could be headed for trouble really fast.

My kids' $7.49 MP3 player came with such a charger, it will provide 1200mA at 5VDC which the MP3 player will charge off of. Something like that will probably handle your fans. If not, then I would look a little harder.

USB power is pretty handy, but there are some things for which is is a poor power source.

i think i am going to try an AC/DC adapter. i think it's the best way. can u give me some suggestions on where to put the fans. I have three fans as i said earlier.

As long as you are drawing in fresh, cool air over the LCD, you can have th fans as an intake (pushing the air into the enclosure) or exhaust (pulling air out of the enclosure) or a combination of both.

If those are small fans, I'd probably space them out along the LCD, and have them as intake fans, blowing over the surface of the LCD. I would use small fans this way, because the air flow can be directed more easily.

For larger fans (80mm or more) I'd use them as exhaust fans, and have them pull hot air out of the projector, and have it set up so that the only air intake will draw in cool air over the LCD. This is a little pickier to set up, but is a tried and true design.

my fans are 80 MM so i think i will do a combination. I think i will put two intake and one exhaust the first intake will be between the rear fresnel and lcd and the second one will be between my collimator fresnel and tempered glass. The exhaust will also be between the rear fresnel and LCD it will suck the air that is coming from the other intake fan so i am going to make it parallel to the intake one. BTW i wired my fans to a mobile charger that's output is 5V and it worked yay!!.


thank you

Don't bother putting the one between the collimator and tempered glass. The LCD is what you need to keep cool, so that's what you should focus on. If you want 2 intake fans put them side by side and have them moce as much air as possible next to the LCD.

don't i have to worry from the rear fresnel to melt because it is going to be 220 MM away from the lamp (its focal length). BTW can the collimator lens stick to the LCD or does it have to have some space between it and the lcd?

I think you gotta do more reading...

No, you need space betwent he fresnel and LCD. If you don't, you will get moire patterns in the LCD projection from the interaction of the grid and circles. In addition, the projection lens will pick up those circles, because they'll be in the field of focus.

The LCD goes kaput at a bit over 45 deg C. The fresnel will be fine until about 100 deg C. The LCD blocks (and converts to heat) 91-95% of all of the light that hits it. The fresnels blocks (and turns to heat) 1-2% of the light that hits it.

The fresnel will be fine as long as you keep air moving. Keep fresh air going into the box, and get the hot air out, and the fresnel will survive indefinitely. The LCD will die a horrible death at temperatures that won't trouble the fresnels at all.

ok, so ill put the two intake between the fresnel and LCD if its better.I just bought new switches for the PJ.

Can a 50 mm diameter triplet with a focal length of 137 mm work with a 15 inch widescreen?
Because i have this lens and if it can be used then i could use it as a spare for my pj that has a 220mm collimator and 330 mm field fresnel. so can it work?
BTW.can a combination of 2 330 fresnels wwork with a 330 triplet?. And also doeas the groove pitch make a difference? i mean if i do a combination for example the collimator is 220 mm fl and has a 0.5 groove pitch and the field fresnel has 330 mm Fl and a 0.2 groove pitch. Does it make a difference?

thank you

I really think that you need to do more reading on design.

A 137mm triplet isn't likely to have the needed FOV, and even if it did, you're looking at a REALLY SHORT throw. Seriously short...

Try the following: Use masking tape to mark out a 120" image on the wall. Make it 63" tall by 102" wide. (This is a 120" screen in 16:10 aspect ratio)

Take a look at it. Nice right? Okay, bow here's the bit where we see how you like this kind of throw... Find a cardboard box, about 12" tall by 14" wide. The other ratio can be anything, but about 20" would be ideal. This will be about the size of your finished projector. Place it so that it is even with the center of your "screen" but have it about 47" away from the wall. This is where your projector would need to sit in order to project your 120" screen. Now, try to find somewhere to sit where you can see the whole screen without that box in the way. Personally, I don't see it happening.

Also, with that triplet, you'd need a shorter collector lens. A 220mm MIGHT do it, but the Focal calc shows only about 155mm between the LCD and the triplet for that FL.

Seriously, you need to do some reading, or else I'm going to end up typing out and explaining the whole guide in this thread... Except that I'm far more likely to just stop answering, which I'd rather not do.

metal, we suggest you use the 'SEARCH' feature above. You will find most of your answers through others experience and experiments.

OK, sorry for asking you a lot of questions. I stayed 4 hours yesterday just on this site so i think i got everything.



thank you very much for your replies (and supraguy).