Hi there, I've been working on making an data projector using the tried and tested method of using and OHP and an old LCD screen. So far everything works , However i'm trying to cool the lcd down as it gets hot and lots of nasty things are about to happen. So I thought that i would use an old PSU from a P1 system I have to power some fans around the edges of the LCD. The question I have, is will the fans alone be power hungry enough not to cause harm to the PSU? It's just I remember a debate about having to have enough load on a psu. Hope you can help. Xalek
Hey there, I'd love to see some pics of your projector and how it works. I've thought of doing that in the past. I think if you're talking about a standard PSU, you can just short the green and a black wire to build a load in (paperclip in the 20pin connector). I converted an old ATX psu for bench testing in a similar manner, though removed the 20pin connector and connected green to black inside the casing. There's some great guides on bittech and elsewhere for creating a bench psu which should apply. http://forums.bit-tech.net/showthread.php?t=150035&highlight=plexi+shroud+cover+psu+side (also, look at his link for the original.
If it's an older AT (Not ATX) PSU with a mechanical on/off switch, then you should be good to go, they had very little load requirements. Mostly on the 5v rail IIRC. The debate comes in with newer PSU's that need to have a load on their rails to actually turn on. No decent PSU will nuke itself because of a light load on the rails.
Thanks for the replies, I've had another few thoughts with powering the fans now (i'll have photo's up by the weekened). Inside the projector there's a coil with different voltages coming of, and I can get 20V AC out of it. Which would ned mean making a rectifier and requlator to bring it down to 7.5v DC..... not as simplistic as i would like. Another thought I had was to take 5v from the VGA connecter, however not all GFX these day's use that pin and also the fans i have don't like 5v for some reason. So I then thought, why not take 7.5V from my PSU in the computer attached to the projector? So what i'm thinking is to use a male molex connector on a pci bracket, so the psu is easily connected / disconnected and run the 2 wires along the VGA cable and heat shrink them together? Also means the fans will always be on as long as the computer is on...... Any idea's are welcome Xalek
if you wanted to use a seperate power suply you could make a relay circuit by conecting the relay input to any power inside the projector that comes on when it does, and the other end between the green and a black wires in a modern psu this should work
I guess this statement is going to betray me as 'not a modder at all', but, in the light of the present price of data projectors; WHY?
Because he can Anyway an "el cheapo" projector will give you 800x600 resolution, while an old LCD will do 1024x768 or 1280 x1024. Xir
I get alot of why are you doing this, and the answer is simple, because i've been given most of the stuff free, and I need something to replace my lego kit I once used to play with... . The panel i'm using is 1280 x 1024 so its a definate increase in resolution, and then there's the bulb replacement costs to consider as well so although that cheapo projector may seam cheap at first, is it really? Whats happening so far: I've striped down my Dell monitor (yes i know its 17", but for £10 could you argue?) and i've started cutting the electronic housing cage ready for mounting on the projector side. When i was in prototyping stage i simply had the screen behind the projector with the data cable coming out of it towards the lcd on the main ferensal lense, which worked yes... but you just had to think of knocking it and all hell would break loose. Once thats done i need to find a way to mount and protect the lcd. I'm hopping to get photo's up before the weekend now, just to show you whats happening. Xalek
It does, but its a high voltage fan, with runs on AC, otherwise I would have just wired it up using the existing circuitry, which would have made life alot easier. Also the current fan is on the rather noisy side (and Very inefficient at that!) so was always going to be replaced by a quieter higher airflow fan. Xalek
