The Photonbrush

Index and Timeline
15-11-06 - Interest sparked in DIY Projectors
21-11-06 - Design Begins, First orders placed
24-11-06 - LCD Stripped
25-11-06 - AG Disaster
27-11-06 - Lenses arrived, Tested panel on OHP, Wiring diagrams and room layout finalised
01-12-06 - Wood purchased
03-12-06 - Box construction commences
06-12-06 - Box is painted
07-12-06 - Lamp arrives, lamp burn in
09-12-06 - First test
10-12-06 - Rearrange room, 2nd Test
11-12-06 - Painted wall, everyday use begins
12-12-06 - Holes cut for switches
13-12-06 - Wiring complete
14-12-06 - Mounted on ceiling, Premiere Movie night (debut)



Photos
http://picasaweb.google.com/plurch/Photonbrush

Current Status
98% Complete
Mounted
Painted
AG Tear needs fixing

The time has finally come for me to begin building a projector. There are going to be some challenging times ahead as we progress through the stages.


DESIGN
LCD: Samsung SyncMaster 730B - Wholesale
Frensels: 220/650 0.5pitch - (editted by dazzzla)
Triplet: 100mm/f500 - (editted by dazzzla)
Lamp: Osram HCI-TS 150W/942 NDL PB - PJ White (Aust)
Ballast: Generic 150W - PJ White

All parts have been ordered and are due to arrive within 2 weeks

Projector will be in a horizontal configuration for simplicity and minimal light loss due to mirrors etc. Projector will eventually be suspended from roof and projected on to a wall which will be painted white. A projection screen size of 2.5m diagonal will be the goal.

The box will be made with plywood and epoxied together using west system epoxy resins. Either threaded rods will hold the panels and frensels or a slotted system will be used. When the parts arrive I will weigh up the pros and cons of each method. The triplet will likely slide in a focusing box or in a tube, also to be decided.

I am going for something which will produce really impressive results. Contrast, sharpness and light evenness are the primary goals. The room which the projector will be in is very light controlled which makes brightness less of a priority. I have some concerns about the evenness of the light across the image. Are there any suggestions on extra steps to take to improve this?

I have a number of reflectors as well as precondensers from old slide projectors that I am going to try once I get the main workings up and running.

Stay tuned for some pictures of the design as well as many more details. Suggestions are more than welcome.

Stripping the Samsung 730B

Stripping the 730B was extremely easy. Unscrew the back panel and it should come off with some light force. All the boards are just screwed down and all of the plugs for the cold cathodes and controller boards can be removed fairly easily. It runs fine with only the two main boards plugged in.

When it comes to removing the panel itself- there is lots of superfluous layers including a huge slab of glass from the backlight panel. You dont need any of this. You take everything out, then put the panel back in the metal frame and the black plastic frame clicks in around it. You can then find some screws to put in the threaded holes on the side if you want it to be really secure. The threaded holes seem to be unused in the actual construction of the panel- perhaps a manufacturing thing.

The only trouble I had was in removing the black plastic frame holding the panel down it was glued at the bottom. At the time I couldn't work it out but you can just peel the glue off.


The panel with all of its layers


Testing the bare panel


Bare panel & bits


Making sure its all still good


Panel in metal frame. If your not going to remove the AG you never have to remove the delicate panel from this frame.

AG Removal Disaster


Soaked with water for 2 hours


Peeled a bit and checked (turned it on) to make sure it was just the AG which it was


So I peeled some more, but it was hard to pull off


So I soaked overnight


And peeled in the morning but the AG tore making it impossible to peel further

I tried the other corners but they didnt peel cleanly either. I have left it as is for the moment and will worry about it again when the PJ is complete.

Proof of Concept





The results were actually ok when all the lights were off. The focus was pretty average and the throw was horrible but It works at least.

Lens Arrival

Click to view attachment (edited by Dazzzla)

Click to view attachment (edited by Dazzzla)

Wiring


Wiring diagram with blackout lamp restrike protection.


LCD Powerboard 12+V Raid


LCD power board

Proposed Room Layout

Box Design





SolidEdge V18
PM me if you want the solidedge files or the dimensioned drafts

Box is 1m long

Box Construction


Measure 2x, cut 1x


Routing the LCD slide groove


Gluing the edges with 2 part epoxy, no screws needed and so strong the wood will break before the glue lets go


No light leakage except for the gap which will be eliminated when the top is finished (I could even make it a ventilation hole)

More photos of the build to come including the frensel slide grooves that turned out perfectly

lookin good....wish I had some advice about the AG

It looks like the antiglare is coming better with about 10% acetone and then cover with plastic to stop it from evaporating.

Just leave it until you have a few movies under your belt. You will be able to see the difference on the screen just incase you kill the LCD.

Construction 2


Vertical Config glued together, unpainted




Horiz config




Undercoated

Lamp Test / Burn in

Powerball, 150W


For the first 3 or so hours the bulb was quite greeny blue in temp. I left it for a good 12 hours for a burn in (I put some stainless steel flashing over and around the box).


After a while the light became the brilliant crystal clear white I have come to know and love.

First Run


Makeshift light blocking, dangling power cables.


Results were super super clear after the first focus session but it was only a small spot. I later found out that the frensels were switched.

Second Run


Frensels the right way around, unsplit config.


No cooling at this stage either

Best AG Comparison Ever


Corner is without AG


Best comparison ever

Wall Painting

So far all the results have been on a greyish blue wall. Painting the wall yielded a huuuuge improvement.


Taped to max height 4:3 ratio screen.


Filled holes with plaster


Painted, roller is a must for supreme even-ness.


Removed tape


Test, notice that there is still pretty good brightness despite lots of ambient light

Paint was just standard ceiling white rolled on.

Wiring

I totally revised my wiring plan to be much simpler. I have a cool safety switch thing that prevents electric shock as well as staying turned off in a power failure which reduces the need for my advanced relay circut. It could be considered a sort of plug in safety switch which I recommend to anyone working with powertools or around water where there are questionable fuseboxes.


Simple switches, few fans, a ballast, an ignitor.
This also shows the simple soup ladle reflector which provides only a marginal increase in brightness but shields the heat really well.


(Front) LCD control boards

Premiere Movie Night

Ignoring the minor focus issues and AG tear, everyone had an awesome time.

Tuning


Testing vertical config- Works well!
You can see the lenses in the slots. The front, tilting frensel has two plywood strips clipped to each side with a hole in the middle of each plywood strip. A short bolt goes through the outer case so that it can pivot from the exact center.


Testing grounding the boards to reduce noise on my sound card (Audigy was playing up)


Looking from triplet hole


Temorary additions to the lamp end. Notice the light shield for the fans (works really well, will replicate in black painted aluminium). Also notice the temp switch which limits the fan speed (47ohm in series) when under 50degrees C.

Test Pics


My favourite colour lady. No colour calibration though, just straight through.


Blown away by the colour. Absolutely brilliant. Some small issues with focus in far edges but super good so far.


Just to prove its no fake and to see my high tech black cloth tape borders (which work super well).

More photos of the mounting to come, please ignore the room and also the shoddy looking box. It is going to have a coat of marine polyester paint as its top coat. Will look very nice.

Purchased a 5m DVI cable, much much much better than the 5m vga one that I was using. A highly recommended purchase for those with long cable lengths.

The projector has come a long way for just 3 weeks or so. I am honestly blown away from the results but I feel that there are still a number of things to do to make it even better.

-2nd Coat of black on inside
-Add hinges/latches to top
-improve and document hoist/mount
-fix minor corner fuzziness
-Address the AG tear problem

Brightness and colour are not a problem despite being only 150W. I was a bit worried when I first put my lenses in and got a dim/uneven image but with proper alignment and lots of fiddling it has come out brilliantly.

Obviously you can really only enjoy it in a dark room but even with a fair amount of light in the room it is readable and I have found myself still watching media on it.

There was a big issue with my lenses in that they were incorrectly labeled with the f220 and the f650 switched, unfortunately one was to be cut a lot smaller so I needed a replacement. They sorted this out immediately with no problems.

I have a really good tip for people cutting the frensels- Get a sharp hacksaw blade and snap it in half and use the half blade to score the acrylic until there is a deep cut when you can snap it off with a clean cut. The coarser the blade the better. I looked at the laminate cutter from the hardware shop but figured that the broken hacksaw blade was pretty much the same thing for a fraction of the cost.

Demo Pics


Over the Hedge DVD


Jeremy Clarkson's the good the bad the ugly DVDrip (Divx)


Good old 5th element DVDrip (Xvid)


Another classic shot


One of my favourite test images is the standard vista background with calculator opened. If I can't see or use calculator then the whole thing is useless. Fortunately it is super clear.

To see these images in full res then head to http://picasaweb.google.com/plurch/Photonbrush

Wow amazing

This is all with a 150w bulb?

Yeah, amazing what well tuned, high quality optics can do when paired with a high efficiency bulb.

The bulb is the 150W Ceramic Powerball

I figured I should give an update. The projector has been working really well for the last few months but I haven't fixed the torn AG yet. I leave it on 8 hours a day and have had no major problems with heat. The 150W bulb is still ample for night time but I have found that it struggles with the ambient light in my room (which is lots).

I dont know how similar my panel would be to yours, but I'm curious to know: was the AG ripping starting at the edges? I know that mine kept ripping from the edges because I didnt have the paper towels going all the way to the edge(about a millimeter or 2 away), and the edges really didnt want to come off. If that's the case, try resoaking the part still with AG on it, then use a razor or x-acto knife to peel up along the edges first. Then peel the rest by hand and it shouldn't tear. I also heard from someone that putting tape along the edge of the AG will reinforce it and help to prevent it from ripping. I just used water on mine, no acetone or other chemicals. I also washed it with soap and water after the AG was all off, and it is still working.

I have a question too-Are you using any kind of UV protection? Do you need any with the type of bulb you are using?

My AG tore when I applied excessive force when pulling it off. If I was going to do it again I would use an acetone mix to aid removal. The problem I have now is that I have no corners left to work from.

As for UV, apparently the glass on the powerball globe blocks out a certain amount of UV. I have no other UV blocking materials other than the frensels, LCD and triplet which in theory should all block some UV themselves. These bulbs are designed to be used in display lighting so I would be surprised if my final picture was particularly dangerous in any way. I think the UV levels would only be concerning if you were working close to the bulb for an extended period of time.

Cool. I dont really want to be worried about gettin lexan or some UV blocker, mostly cause I'm not familiar with it and wouldnt know how to cut it to size. It's probably easy, but oh well. Also, when my AG was ripped, I restarted it from the edge where it's torn, its almost as good as a corner and its out of the field of view, in case you mess up!

The main reason people use the lexan is to block radiant heat from the lamp. The heat problem isnt as great with the 150W bulb.

I have had an issue where DVI input has suddenly stopped working on the panel controller. I think it may have been due to a power failure or something like that. I'm not sure if this is something I will be able to fix because I cant see any damage on the panel circutboard itself.

Just curious as to how much your lighting cost you? ie lamp and ballast etc? I'm in Australia and am just getting pieces together for my first boxed PJ (previously just did the OHP style) and am trying to find a reasonably cheap but still reasonably bright lighting option.

I'm starting to be tempted to just see if I can rip the lighting rig out of the OHP I have currently... but if your setup was reasonably cheap and gave good results then that might be my choice.

Love the design too by the way.

From a lighting place in Adelaide

1 x HCI-TS150W/942 power ball - $ 85.80+GST

1 x Ballast to suit - $56.54+GST

1 x lamp holder to suit - $9.68+GST

1 x igniter to suit - $35.20+GST

results are extremely crisp, see my other plog for the revised design.

you mentioned you got nice eveness to accurate condenser placement. Do you mean a glass precondenser? can you tell us more about that? which condenser, how far, where you got it etc...? Do you think using a condenser with 15.4 lcd and 330mm fresnel would bring same results?

awam was last on the forum: 18th October 2008 - 06:45 PM (according to his profile)
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