Ok, all before I start, I am pretty inexperienced with projectors as you may be able to tell, with this being my first build. I don't have many tools either, so my enclosure may not look great

What i do know, is that i want a good projector and i'm not too bothered about size.

I chose the MKIII design, because it is a bit smaller than a straight through one, and seemed more interesting to build in my opinion (please tell me if i'm being a bit too ambitious!)

Anyway, the parts I have so far:

I have a 3M 1850 OHP, and I would like to use bothe the triplet lens and the light source from this. I looked it up on the internet, but found that everywhere I look, the specs (lumens etc) are different for it. I think that it has 2 interchangeable 2500 lumens bulbs. I would like to incorporate this bulb changing mechanism into my design. The fresnels from the projector are not wide enough for the 15" TFT, so I will need to purchase some fresnels for the PJ.

My first big question is about matching the fresnels to the triplet lens. Again, looking around on google, i found that the lens from the 3M projector has a focal length of 11.5", so what fresnels would I need for this? I am in the UK, so a source for the fresnels would be great too

I also have the 15" TFT Monitor (Has antiglare and back seems shiny)

So yes, sorry about the long read, and I hope some of you get back to me. I can provide any pictures, and when I actually get going, I will chart my progress on here.

Link to the MKIII plans:

Here

Dan

If the bulb is indeed 2500 lumens, that is not nearly enough. my bet is that is the spec on the projector rather than the bulb. either way, the life on most OHP bulbs is ridiculously short (10s of hours), and not really that bright. If you must use an OHP, I'd suggest one of the dukane OHPs with the 575w hmi... 49000 lumen bulb

Thanks for the quick reply.

I checked out the bulbs themselves, and found that each one is 14500 lumens?? Is that a normal value, even if a little low

I don't want to spend loads on a new light source at the moment, since i spent a bit of money on the OHP stupidly. I may try it with these bulbs, then if when i get fed up of the brightness, I will upgrade to a larger one.

OK, so the bulb is a 360w MR16 halogen... the color should ok, but you still have to deal with LCD transmissivity and losses in the lighting system (only capturing part of the 360 degree field, losses in the condenser, fresnel, reflector)... so, bottom line is you will get roughly 10% of those 14500 to the lcd, it will let through roughly 7% of the remainder and roughly 70% of that will make it to the screen. so, you're looking at 70 lumens give or take at the screen. usable in a very dark room, but probably not what you were shooting for. I'd sell the OHP if you have not already torn it apart and start with a different light source myself. The 575w HMI OHPs are a good option for cheap, bright light engines (saw one go for $33 USD earlier this week on US ebay, but that was extraordinarily low for even a used one... more commonly in the $100 range recently). Also, the OHP you have has a singlet lens, you'd be better off with a triplet. Keep an eye out for the Dukane models 670, 680, 681 and 683, as well as 3M 9850 and elmo solar series. I know the Dukanes at least have triplets and an e-ballast with the 575w HMI (do a search here, lots of info). the ENX bulb in the one you have has a life of 65 hrs, the 575w hmi has 750-1000hr life, and the standard metal halide options are in the 10-20000 range.

cheers.

I will be sending the OHP back then, since it arrived with a broken mirror anyway, which wasn't in the item description.

After seeing those shocking figures, I decided to get a proper source. I was looking at the mega kit, since that is an easy way to get all of the right parts, but i am living in the UK. Has anyone tried shipping this to the UK, and if so, did they get charged customs charges?

If customs will cost too much, I am finding it extremely difficult to source the parts from uk suppliers. (Sorry if posted before, I tried searching) Any ideas?

Thanks a lot for the support all,

Dan

I understand that the Custom's charges, VAT and such can make for an expensive shipment to the UK.
You can check the Global DIY Projector Community section of the LL forum.
Not to detract anything from Lumenlab, but I found the following site: http://www.diycinema.co.uk. You might be able to ask for help with sourcing local parts there.