If you are sure that you can have adequate airflow under the box, then an intake from the bottom and an exhaust from the top would most likely be better than the wiki design.

@Igu: I got a Nutone Attic Thermostat. Did the research and I installed it. Works perfectly. It has a 10 def F deadband (how much delta Temp before the fans would stop after reaching setpoint).
The company I got it from is the Ontario dealer for Nuton:
Inventex
www.inventex.com
Tonronto, Ontario
1-800-387-2844
I talked to Diane (1 month ago)

It is a Nuton model RFTH95
was $32 + shipping + tax
1-1.5 weeks for delivery.

I recommend getting this thing. I have my system start the fans when the master switch is powered. Once the temperature reaches about 90 deg F the thermostat engages direct power to the fans. When the main switch is turned off, the fans continue (not on switched power) until the thermostat reaches about 80 def F. So no need to remember to shut the fans off when done using the PJ.

For a picture of the thermostat, look at my blog here: http://www.lumenlab.com/forums/index.php?showtopic=11318 which also directs you to http://spaces.msn.com/tbirdmvp or http://photobucket.com/albums/b294/Tbird1234/

Good luck!

looked on the website and couln't find the thermostat you got...doesn't seem to be in their inventory unless I'm just not seeing it.

Tried looking for an attic thermostat at all the local hardware stores, and they all look at me funny, and point me towards the round ones that are the regular house ones. Quite frustrating...

Even if it is not on their web site they are the Canadian Nutone dealer and can get any Nutone product. Go ahead and call them up.

http://www.ventingdirect.com/ProductDetail...&source=froogle
is this the one?

That is the exact one I have. It's been working great!

I have a quick question. I'm building an unsplit pro setup with the T15 bulb. I will be using a piece of X10 Lexan as a UV blocker with adjustable distance between the rear fresnel and the bulb. I plan on venting in air right behind the LCD, but I'm wondering if I should route the air flow between the fresnels, which will be 5-15mm apart?

Also, anyone looking for high CFM, quiet 120vac fans, check out www.orionfans.com. I'm sure these have popped up before, but they look to be excellent. 120x120x38mm fans, 110CFM at only 37dB. 70CFM at only 30dB!!

No dont run air between fressies, as they will bow signifgantly due to temp differential,, if you wanna see what i mean, when you clean one run hot water over one side and see how they become convex, then run cold and see how quickly it snaps the other way,, cool air will have same effect,, they are best out of any airflow,, panel is main concern..

and also dont go under 10mm seperation as you will get star burst patterns on screen,, and make sure the bullseye's (optical centres) are perfectly lined up too, when mounting the fressies...

ok thats what I wanted to know, thanks!

another question. here's the setup: air being pulled from top of enclosure down the back side of the LCD, then under both unsplit fresnels. Should I then route the air up the back side of the fresnels, between the collimating fresnel and the Lexan, or should I route it under the lexan as well?




what if I were to matt the collimating fresnel directly against the lexan?

That is what you would usually do. You put the collimating fresnel and the lexan together in the same frame.

so if that were the setup, air would flow down the backside of the LCD, then under both fresnels and the lexan, and into the bulb chamber.. then the field fresnel would be cooled while the collimating would not see any air flow.

kind of just talking to myself here

You would have the Lexan/Collimator Fresnel/Field Fresnel sandwiched together then an air gap then the LCD. The air would come in from the top air hole (from outside the projector) down past the LCD (bulb side of LCD) and Field Fresnel (lens side of fresnel) go through an air gap at the bottom of the Lexan/Collimator Fresnel/Field Fresnel frame then into the bulb chamber.

I just found this site yesterday, trying to soak up all I can before I take the plunge into DIY projector building. Don't know if it's been mentioned before in this thread or not, but in regard to using attic fan t-stats, be aware that they aren't the most accurate in the world. I'm an HVAC repair tech, so I have a little bit of experience with them. They seem to fit the mold of budget projectors perfectly as long as they stay calibrated: cheap, workable temperature range. However, because they are simple bi-metal strip t-stats, they can swing way out of calibration. I've seen them as much as 20F off after only a few months of operation.
I don't see any problem in using them, and will probably use them with my first build, but I do recommend testing calibration with a trusted thermometer right out of the box and later during test run with projector at normal operating temps. You can even write your "actual" temps on the setting plate, though if it's more than a few degrees off (5F?) I'd trash it and get another.
If you really want to be safe, it might be a good idea to periodically retest the calibration and even wire a bypass switch to manually flip on the fans incase you notice the buggers have been MIA during use (haven't built my baby yet, so I don't know how noticeable the fan noise is considering normal audio).
Maybe this is overcautious, but I like to be "better safe than sorry." Would much rather replace an el cheapo switch than an lcd screen.

if you place a fresnel - lcd - fresnel setup for a vertical projector....should you put glass on both sides of each fresnel? should I worry about the exposed fresnels bowing from the lcd heat if each fresnel is 20 mm away from the lcd panel? thanks

also, i'm only worrying about the lcd because I've seperated the bulb and the lcd with some tempered glass...hurrayy!

I've finally built my projector. I gave it the heat test and it held at 92f up to just over 2 hours. Then it soon jumped to 100f. I let it sit for 3 hours total and my meat thermometer looked like it might have been nudging just over 100. How can I get it cooler? I'm using two fans from lumenlab. The only thing I can think of is that I cut my cooling slot too big. It's sealed on the top of the glass heat sheald but is open over the first fres and lcd. Do I need to seal it on the lcd? Front fres?

If less than about 104 deg F at the LCD then it is cool enough. Only issue is if the room get too hot or humid than the temperature will rise higher in the projector.

Thanks for the reply. I already tightened up the slot on top and that seemed to make a huge difference. On the floor it holds at 82f or so. Mounted on the ceiling it holds at about 94f. The room is cool but the intake is on the top so it gets a little warm up there. However, the fans stopped working and I didn't know it until the screen showed that it was melting. So I've ordered supplies and am putting in a kill switch for when it gets too warm. Ugh!

My setup is the picture on the right.
I have yet to run with the lid on and a thermometer.

Hi All,

I was trying to figure out how big of an intake port I would need to ensure the cross sectional area is the same as that of the exhaust port. (laymens terms.. how big does the cooling hole have to be to be the same size as the hole(s) at the back of the projector with the fan(s))

Came up with this nifty calculator so I thought I would share it with you...

http://insomnyak.centelia.net/box_calc.htm

You simply enter the number and size of your fans, enter a width or a length for your intake and the calculator will work out how big the intake has to be to match the exhaust.

ok so I'm getting some mixed messages here..from everything i've seen in the past, the air is supposed to "snake" through the rear fresnel/heat shield. In my setup, the air will come in from the bottom between the lcd and rear fresnel, then it will go up and over the rear fresnel, then down between the rear fresnel and heat shield..then under the heat shield. Finally I'll have 2 120mm fans at the top left and top right of the back of the box. In the "lamp chamber" I'm only going to have the lamp/ballast/and 12v wall wart for the fans, the coil ballast will be mounted outside on the back of the projector with a cage around it to allow passive cooling and prevent burnt hands .

Sorry for this slightly off topic post.

What happens if two or three fans are placed in series instead of parallel (Meaning if one fan is used to accelarate the air for the fan behind it instead of each fan dealing with its own share of air)?

Is there any relevant rule or formula on this like, voltage getting increased in series batteries and amperage getting increased in parallel batteries?

Fans in series has following benefits -
1. Less light leakage for intake and exhaust hole.
2. Only on Air conditioned filter (to keeps the dust away) can be used instead of many and hence lesser reduction in airflow efficiency due to these.
3. Lesser number of screwes on the body and hencre better looking box.

(assuming that one IS using multiple fans like three 40mm fanns for one 120 mm).

Any insight will be helpful.

Silent cooling ... a good goal.

I wonder if an ionic wind type of approach might work for us? You know those fans that run on electrostatics (TT Brown stuff) ... inducing an air flow with high voltage differentials?

Might be cool. (pun intended)

WOW the Holy Grail of Quiet FANs?!!!!!

90 CFM!
and ONLY 18DB!!!!


I ordered one, am using a standard square box design (15') and cant wait to replace the delta whirlwind lol
works great just a tad too noisy for my taste.

After searching far and wide i found a company called silenx http://www.silenx.com/index.asp
if its tru about that 90 cfm fan only being 18db im going to be SOOOOOOOOOOO happy.

the delta im using currently pushes 130cfm , and im using a box with tempered glass in front of the rear fres, im thinking that silenx fan and maybe another super quiet fan mounted on top to help push the air through the box inbetween the lcd and fres and should be good? Im gonna try that and drop a temp down to see how hot it gets, ill post notes on it soon as i get it and install it hopefully will be here in my mailbox next week. YAY wish lots of luck all cuz i think we may have found the holy grail of quiet high output cfm fans...

IT WORKS!
WOW!
my pc is now louder than my pj! lol
i can feel a significant amount of air being moved out the box and still feel a cool air flow from the top of the box. I went ahead and added 2 small fans over the vent between the lcd and frensels to help push the air through the box to help compensate for the missing 1/3 of air flow i used to get. With the delta 120 i was using the box wouldnt even start to get hot, with the silenx the back compartment of the pj gets kinda warm but the area with the lcd fresnels seem to be keeping cool enough. I dont have a temp guage yet so i only ran the pj a few hours and just kept spot checking the box. So like,. im shocked and amazed. I want to get a silent power supply now to go with my pc and i think im in pj heaven all over again!!!!

oh btw i figured out im not use the newer hass style box heh im using the old skool style hass box the one that lokos like abig shoe box or sumthing u bury a large animal in lol but it works oh so gooooD esp now thats its insanly quiet. Watching quiet parts in moves now is like wow i cant explain how nice.

go silenx!

This is going back to the original posts about protecting your PJ from overheating.

Something I think is a good idea is to always use 2 fans, that way if one fails you always have the other one.
I have seen lots of 'sleeve' bearings fail and lock up the fan but never with a ball bearing fan, a ball bearing fan will start making noise long before they fail.
Just my 2 cents.

Good advice, 2 fans is a good idea, also then you can use lower CFM rated fans and get the same airflow with less noise.

Check out this fan. I am not sure it's the best, but I already order some, haven't test it though.

http://www.newegg.com/Product/Product.aspx...N82E16811999145

The nice thing about this is that it has a max constant speed, a manual nob control, and a temperature sensor.

You can only 1 of the three. I plan to use the temperature, so that I don't have to fudge with timer or things like that (at least that's what I hope it'll work). I'll see how well it'll work.

i was thinking about buying some of those as well. I would love to hear your thoughts on them when you get them.

The fans work well. The noise is high if run at full speed. I turn it down (using the dial controls) so it's not very loud. With audio, it's not noticeable, but if no audio, then you'll hear the sound clearly.

I didn't use the temperature sensors because at room temperature, they still run (not stop), at low speed.

I learned that I can make the box very cool without blowing too much air. It's the way of capturing all the wasted heat from the light box and blow them out without allowing them to escape into the box. So for those with heat problem, build a good INSULATED light box with a fan sucking air out of this box (make sure to have an inlet for air to come in to this box from inside of the projector case), and blow hot air directly outside of the projector case (using a duck pipe for example).

I agree with this .. I own a fire Equipment company and a vent hood cleaning company , we install commercial restaurant vent hoods.. by using a return air and duct work system you only keep your air flowing with in a given field.. However this should be figured by the actual area in the box.. Duct work size is very important.. Small ducting is good for pulling air fast to remove grease and smoke , but we are talking about heat..so a large duct work with a a oversized fan would work good.. Radio Shack has a fan for about 13.00 that is about 6" round... for the top of the box one large slot looks to be fine but if we install 1 or 2 smaller fan with roughly the same total cfm as the exhaust we will have a return air system thus forcing the outsie cooler air down and exhausting it out the back of the box.. I have found that 2 small 500 cfm proccesor fans work really well.. Basically this setup will cause cooler air to be forced down over the area and exhausted at a faster rate without alot of noise..

Hi

How would you wire up a 3 pin computer fan to a 12v power source and whats the extra pin for

Thanks

Hi Again

One of the other PJs was fluorescent and had 4 full spectrum fluros
Could we do that in this setup to reduce heat so the LCD doesn't overheat

Hi

Am i the only one using this plog
Where in Australia could i get a cheap LCD
Ive looked through the major suppliers in my state and i cant find a cheap LCD

The third wire is to keep track of the rpm of the fan. On a computer if the fan rpm drop below a certain threshold the computer will sut down.
You can disregard the third wire. Just use the red and black.

Is there any way you could monitor the rpm through a homemade curcit instead of usin a pc's curcit

I presume you could but I can't help you how to build one.

Thanks Anyway i'll ask round tho

This might sound like a noob question so how does the computer monitor the speed through 1 wire

My guess is that the third wire returns a variable voltage linked to the fan speed. Someone might try passing it through a volt meter to check it out.

I don't have much projector experience but I do have a lot of over-clocking and case modding experience. Is there a reason that heat sinks and cooling fins aren't used more often? By wrapping the lcd and perhaps a heat shield in an aluminum frame with fins sliced in it, you could effectively double the surface are exposed to air currents.

l_l_l_l_l_l_l You could cut groves like this in the aluminum frame where the air flows past. Aluminum is a soft metal and can be easily worked with a cut off saw, or some cross cut blades on a table saw. (use safety glasses) Brass, copper, and silver would also work but is more expensive and are harder metals to work with.

The more metal used and the more fins the more effective this heat sink would be. Use of a good thermal paste or pad when attaching the metal to the objects would also help. A thermal pad might "soften" the contact between LCD and metal frame reducing the chance of a cracked LCD.

I'm about to start my first project so any comments would be appreciated on the subject. TIA.

Hi Everyone! Just thought I'd add this to the cooling thread. For some reason it won't let me start a new topic, but it does fall under cooling.

This is a quick easy way to make an adjustable fan controller that will turn on under 3 conditions.
1)Lamp on, diodes all below preset temperature.
2)Lamp on, diode(s) above preset temperature.
3)Lamp off, diode(s) above preset temperature.

It will turn off when the lamp is off, and all the diodes are below the preset temperature.

This is how it's built http://sound.westhost.com/project42.htm I used the top diagram, as I will have a 12v regulated supply in my projector. This meant that I could skip the 10V zenner and soldered a piece of wire in place of R5 (I'd already premade the circuiit board without thinking about it...).

Anyhow, as is, the circuit will only be temperature controlled. You can use as many diodes as you'd like to trigger the fans. So long as one triggers, th fans will start and run till all the diodes are beneath the preset temperature again. To get the circuit to also be triggered by light, I soldered a LDR that goes from 0.5M Dark to 27k when light falls on it in parallel to the diodes.

To get everything setup how you want it by way of the temperature it triggers at, set it with the LDR IN THE DARK. Otherwise, when it gets pitch black in your box, the fans won't keep running till the diodes hit the temperature you want. They will just stop when your lamp does.

Oh, and one last thought. If you're planning on running multiple fans in parallel off this thing, then I'd suggest changing the diode . The specified one will fry. I went with one with a 36W rating. It's a BD682. I also removed R8, so I can get a full 12V across the fan.

Works a treat,
Bev

Hope someone finds this useful. If you can't be bothered etching a circuit board, you could probably make it out of varo board with a bit of luck.

EDIT: Place the LDR somewhere in the case that extremely dark when the lamp is off. In other words, place it somewhere where it is not going to catch daylight coming through the lens. We want the diode to go from one extreme to the other. (from as close to 0.5M to as close to 27k as we can get). This should mean that the temperature calibration won't fall out of place due to variances in the resistance of the LDR. The LDR needs to be in consistent dark when the projector is off, no matter what light is coming through the lens into the projector box (reasonable daylight that is..... not like someone shining a flashlight in the lens). However, it also needs to be positioned so that enough light from the lamp can hit it to trigger the fans on startup.

This circuit has a million and one uses. It could also be used with a latching relay to make a adjustable temperature cutoff for the lamp. Come to think of it, I might just do that.