ace3000_1 said:
How to polish the reflector inside?
I guess it is split - one side is smooth and another side is grooved
You meant even 1 cm FL difference will make difference? I have another 200mm FL frsnel, can I use split design?
Ok, from looking at your reflector in the previous pics it looks like it has a rough surface, we want this as smooth as can be so you need to get some 800 grit sand paper ( emery cloth) and sand it with water, then get some 1200grit sand paper and do the same until all of the previous sanding marks have gone, but make sure you use water and do it evenly. You could go to a 1600 grit if desired but the 1200 should be fine. Ok now the surface is perfectly smooth and not scratched, get some metal polish, i recomend brasso as its the best for bringing a mirror shine, and it has an abrasive cut back in it, ( about 2500 grit). You will find this will take alot of time but its well worth the effort. With brasso it gets messy, the metal will resedue black and this needs to be buffed off with a ribbed cloth, after doing it for some time it will be exactly like a mirror. The smell from the brasso also is flamable, but after the metal is polished its fine to use a bulb around it in the reflector. I recomend to use rubber gloves while polishing so you dont get black hands.
Yeah that dont mean anything cos page maggs are the same, infact all frensels are.
Well 1mm makes a big difference in mine, thats mm not cm's. A 3cm lens movement covers my whole focal range from 50inch to 150inch projection size.
Split design is ok in your projector and its somthing id recomend with your frensels. Make sure the rings of each frensels line up with each other, thats very important and make sure the center of the reflector matches up with the center of the frensel, place the lights arc 200mm from the rear frensel and it should work. The only problem you may face is that the light might not light up the corners of your lcd, this will depend on the reflectors radiating pattern.
Trev
hmm, couldn't find the 800/1200/1600 grain sand paper at home depot. another problem is my reflector is made by aluminum, brasso cannot be used on aluminum:
8 ounce liquid Brasso cleans and polishes brass, chrome, stainless steel and pewter.
Not for use on aluminum, silver or lacquered finishes
any other polish i can use? how sbout the polish for aluminum wheels?
8 ounce liquid Brasso cleans and polishes brass, chrome, stainless steel and pewter.
Not for use on aluminum, silver or lacquered finishes
any other polish i can use? how sbout the polish for aluminum wheels?
go77306 said:
Try an auto shop to get the sand paper, they will have it for sure, make sure they sell paint first and it should be in the body section.
The brasso can be used on aluminum, they say it cant be used because it takes the laqour off of protected aluiminium and it also effects the anodised aluminium, ive used it heaps of times without any dramas. The brasso i use is in a tin and has cotton wading with it, the brasso is in the wadding, mines made by alladin not by brasso but its the same stuff.
Trev🙂
I use brasso and paper towels to fine polish aluminum spinning on the lathe all the time after going through two progressively finer emery cloth sandpapers first and then #0000 steel wool.
It makes a very good near mirror finish.
It makes a very good near mirror finish.
Thanks! I will try to find sand paper today.
I put all the stuff in a box, however I see a big circle on the screen... guess the lamp is not in the focus of the reflector?
BTW the temperature on the lcd is 32 C, but if I put my hand on it, I feel lot hotter.... is this normall? waht is the maximum degrees for the lilliput?
Thanks
I put all the stuff in a box, however I see a big circle on the screen... guess the lamp is not in the focus of the reflector?
BTW the temperature on the lcd is 32 C, but if I put my hand on it, I feel lot hotter.... is this normall? waht is the maximum degrees for the lilliput?
Thanks
No matter how hard I try I just cann't get the lights evenly distributed on the fresnel. Here are two pictures:
The lines on the board are slightly larger than the size of LCD.
I compared the 6v spot light (not the one chasse is using), it projects circles.... Will the 2 million candle power soptlight has the same pattern?
The lines on the board are slightly larger than the size of LCD.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I compared the 6v spot light (not the one chasse is using), it projects circles.... Will the 2 million candle power soptlight has the same pattern?
An externally hosted image should be here but it was not working when we last tested it.
Single fresnel design.Should the projection lens on point A or point B? The FL of the lens is 240mm, and if projection lens must focus on the LCD, therefore it seems to me if I want to get a clear image i should put the projection lens on point B.... is this correct? The reflector is a parabolic reflector. The problem is if I put the LCD upside down, and I can get a correct image (upside is up) on the screen. So it seems indeed I put the lens at point A.... but in theory, it cannt be at A... what's the problem?
An externally hosted image should be here but it was not working when we last tested it.
Here is few test images (design 2, split fresnel)
Why the image is still dark? and corners are out of focus.... I don't have a box for them yet, so there are lot of indirect light on the wall, will puting all things in a box make lots of difference?
I will try to polish the reflector see if it makes any difference.
What is the maximum temperature for lilliput? the LCD surface is around 36C now, is it ok? I have a 120mm >80cmf fan blow air to the lcd, why the lcd is still so hot?
Thanks
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Why the image is still dark? and corners are out of focus.... I don't have a box for them yet, so there are lot of indirect light on the wall, will puting all things in a box make lots of difference?
I will try to polish the reflector see if it makes any difference.
What is the maximum temperature for lilliput? the LCD surface is around 36C now, is it ok? I have a 120mm >80cmf fan blow air to the lcd, why the lcd is still so hot?
Thanks
I am not an expert but judging from what i learned and experienced, the fresnel lens focal should be equal or little higher than projection lens focal.
But i think if it is possible to use a fresnel lens with lower focal length than projection lens but the focal length differences should be minimal but honestly i don't know how much.
I guess you should try replacing your fresnel lens if possible to see for yourself if it is true.
I am closely following your work and expecting excellent result because i am planning to build a smaller projector but not the liliput. i have found an lcd with 350cr.
I hope you will soon attain excellent result.
You'll never go wrong because Trev is actively supporting your work.
But i think if it is possible to use a fresnel lens with lower focal length than projection lens but the focal length differences should be minimal but honestly i don't know how much.
I guess you should try replacing your fresnel lens if possible to see for yourself if it is true.
I am closely following your work and expecting excellent result because i am planning to build a smaller projector but not the liliput. i have found an lcd with 350cr.
I hope you will soon attain excellent result.
You'll never go wrong because Trev is actively supporting your work.
Thanks! I want to know if adding a condenser will make any difference. BTW, I bought the fresnels (200 mm focus length) and fuji copy lens (240mm) from diybuildergroups, and I was told this conbination works perfectly.
Condenser lens will give a very positive result (kindly read my magnifying lens impact on my pj also) base from my experiences.
I guess only the diybuilder group can give u the best recommendation regarding your project. If they say it will work then ask them how.
To solve this problem, i guess you have to call their attention. I believe they will be willing to be of help.
I am a regular visitor in their site. i trust their judgment.
I guess only the diybuilder group can give u the best recommendation regarding your project. If they say it will work then ask them how.
To solve this problem, i guess you have to call their attention. I believe they will be willing to be of help.
I am a regular visitor in their site. i trust their judgment.
Your problem is the reflector,the hole is too big for the lamp and the surface is not reflective enough.
The reflector has to be chrome plated,this is very important and the cone of the light has to be large enough to cover you frensel at the focal distance.
200mm or 9 inchs frensel focal is definetly working with the setup you are trying to do.
If you cant get a 6 1/4 inchs cone of even light on a white sheet of paper at nine inchs from your lamp ,change your reflector.
Remember,on my setup a 5 inchs reflector did not work.
Everything is critical on that kind of projector,if one part is less quality than it should be,all the setup wont work.
I hope you will continue your good work.
The reflector has to be chrome plated,this is very important and the cone of the light has to be large enough to cover you frensel at the focal distance.
200mm or 9 inchs frensel focal is definetly working with the setup you are trying to do.
If you cant get a 6 1/4 inchs cone of even light on a white sheet of paper at nine inchs from your lamp ,change your reflector.
Remember,on my setup a 5 inchs reflector did not work.
Everything is critical on that kind of projector,if one part is less quality than it should be,all the setup wont work.
I hope you will continue your good work.
Here is my box and images/..... still TOO DARK! what is wrong?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
If I put the projector 1.5 meters away from the screen, and after I adjust the lens/lcd position to get a focused image. Howerver, if I then move the projecter 4 meters away from the screen, the image is not focused anymore, I have re adjust the lens/lcd position. Is the something wrong with my setup?
Chasse:
I went to walmart, I only found the Coleman 2 million candle power spotlight in auto section, and the size is 5" not 5.5". Can you please tell me what is the brand of your 2 million candle power spot light?
I went to walmart, I only found the Coleman 2 million candle power spotlight in auto section, and the size is 5" not 5.5". Can you please tell me what is the brand of your 2 million candle power spot light?
An externally hosted image should be here but it was not working when we last tested it.
chasse said:
Ive got a 4.5inch parabolic here that works fine on mine, your brightness issue i think you will find is your frensels being too far apart, also the bulb in the reflector has to be right at its focal point or you will loose one hell of alot of light.
Trev
Trev
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