This is the schematic for a simple r/c decay timer to shut down your fans on power off. The kit for this circuit is here. I'm sure the kit for just the r/c decay circuit is available separately.

Hi Brain,

Has anyone built and used one of these? ...or is everyone just using two switches for light and fan.

Whatever the answer, what's the reasoning? Any problems with either setup?

Thanks,
Mark

Everyone is using 2 switches. I will build one of these whenever I get a chance. The only reason for using this is to make it easy to cool your fan after shutdown. The parts for this timer would be around $10.

Hi Brain,

It looks like a neat project. It seems every time I do a little project like this, there's either a design flaw or I screw it up somehow. I usually end up troubleshooting till I get it to work. I really only wonder if the kit is pretty well proven or not.
Seems like it would be good for the family's forgetfulness to cycle switches right for shut-down cooling!?

Mark

Mark, this is got to be the simplest timer circuit. It's the classic r/c decay timer so there's very little to go wrong.

Brain,

Well, I guess I might be waiting for the other stuff to show up. I'll order the kit and try it out.

Mark

I'm contemplating using a temperature sensor for possibly two things:
1- As an automatic shutoff for the fan (as opposed to a timed circuit)
2- As an automatic shutoff for the lamp to prevent overheating if the fan died or something. This will protect against destroying components (LCD, Fresnels, etc.).

I'm extremely busy at work lately, so if anyone wants to take a look at this, go for it. Otherwise, I'll try to get some schematics done. Hopefully, I'll get some time this weekend if my wife doesn't bug me to do too much

If you find a temp sensor that triggers at the right temp, I'd sure be interested in seeing a link to it!

I was planning on using the LM34DZ temperature sensor and putting it through an Analog to Digital converter. Check the datasheet for how to wire up the LM34DZ to an ADC.

Link to Jameco LM34DZ part

Then you can pick what temperature you trigger on by doing simple digital logic. That's the easy part. The hard part is taking that digital signal and turning on/off the AC to the Lamp.

And you can even have multiple triggers using the ADC output so at a different temperature (using different digital logic) you can turn on/off the fan.

tmmac: replying to your question in the other thread, I posted this elsewhere in the forums:

Well, Ok then.

I just read that data sheet for the LM34 front to back.
I think maybe a quarter of it sank in. I'm doing pretty well to be able to grab a VOM, find ohms on the dial, and remember to turn it off when I done.
I better stick with the educational timer kit.

All the ideas you guys have for these circuits do sound pretty cool though. I think I could build you circuits from schematics, but I'm not going to be any help with the design.

Mark

Hello everyone:

If yor looking for an After Cooling Device check out this unit from Directron.com.
I am using one on my home built P4 PC and they work great. You adjust the amount of time you want your fans to run (1, 3, 5, or 10 minutes) after you turn off the lamp.Runs fans after shut down I'm ordering another one for my projection project.
Also if anyone has any info on a temperture switch like tryn2havefun used on his I would be greatful.

SACK4000

Neat.

Brain,
I'm a total newbie when it comes to building this projector and I will like to add a timer to my yet un-built box. Your time delay design looks too complex for me. I did a little looking around and came across these items. Maybe a new design using some of these components will make it easier to the untrained. If these items are of no use then maybe you can sell your design as kits once you finish it. Thanks.

Thermal switches:
http://www.hoffind.com/thermal.htm

All types of time delay relays:
http://www.ametek.com/product/ProductCateg...ategory_Id=3403

Dont know if these will work:
http://www.antec-inc.com/us/pro_details_co...hp?ProdID=75012

Here's RCL's wiring diagram, makes it super easy for you:

hmmm?...
I was talking about the r/c decay diagram at the start of your post....thats the one I dont get.....sorry if I was not clear...

elduke, sorry this wasn't a response to your post. It was mentioned that I should make a sticky out of the super simple wiring diagram so I stuck it in here. I checked out your links yesterday, seems like some cool stuff. Didn't see any prices though...

sorry if this is a dumb question but i am a newb. where does the first ground wire connect to, i can see the second ground wire is connected to ballast frame.

also, is the line in just simply a standard grounded wire plug?
lastly is the capacitator absolutely crucial? i dont see it in the guide version of the wiring diagram.

The grounds get connected to the green wire in which is part of the line in. The line in I use is a simple 3 conductor computer cord. If you are using the electronic ballast there is no cap. If you are using the coil you should use the cap.

brainchild ty very much, u have been very helpful to all of my dumb questions. i'd like to ask a few more dumb questions...

first, is the ballast kit on the lighting and norpro page, coil and core? and if so will it be compatible with the "eye" lamp and norpro reflector.

also please confirm if this is correct. i only need a ac/dc converter (wall wort) if i use a fan that is dc. if i use one that is ac such as the artic, then i will not need a wall wort.

also what is the ring for with the norpro bowl?

i realize these are very simple questions.. i'd like to thank everyone in advance for any help at all.

The ballast kit that is offered by lighting unlimited is coil and core and is compatible with the eye lamp. The norpro is used with the eye lamp after cutting a notch for the lamp. The ring is a base for the bowl which some people use when mounting the norpro to the back of their enclosure. I just drilled through the small flat spot at the bottom of the bowl and mounted that to wood without the ring. You will only need an ac to dc adapter if you are using a dc fan. Hope this helps.

I am a newbie to this. I have received all components. Managed to strip the monitor - no FCC issues.

Right now I want to get your inputs before I throw the switch on. Here is my wiring - ignoring the switches and the ground wire.

Does it look alright?

Looks good. What monitor did you strip?

LTM150XH with a TV Tuner - this is a kit I got from eBay.

i just have a few questions...
i am using the coil and core ballast...

what is the best way to ground the ballast... in the installation instructions it says to use a self tapping screw... i just want to know if i can just use the bolts that came with it.

also would it be ok to ground the lcd to the ballast frame, sharing a screw with the line-in ground wire?

lastly, is there a specific type a metal the screw should be for the ground to the ballast frame?

You don't need anything special, just use a screw you will use to hold the ballast down.

Can someone update RCL's wiring diagram for the new electronic ballast, if that makes any difference? Also I was reading in another thread about using a dpst switch instead of two switches like in the diagram along with a thermal switch for the fan, can this be updated as well?

Thanks

The wiring diagram in the guide is appropriate for the electronic ballast.

awesome.

i have the core and coil m59 ballast and im wondering which socket pigtail (black or white) will get connected to the cap? which color gets connected to the com wire on the ballast? or does it matter?

thank you for all your help,
-joon

Black to cap, white to com.

What type of wires do I need to use inside the projector? In conjunction with the wiring diagram in this thread.

P.S. I know very little about 120 v wiring.

12 or 14 gauge.

Do you forsee any problems with hooking a temperature switch in the circuit so that the fan comes on only when the temperture set point is reached?

I use a temperature switch. I got one of those attic fan temperature switches from Lowes and hooked it into my system. It works great.

You can do that but you might look into what some others have done. In this thread they show you how to wire it so that your thermostat will keep the fans on even after you have shut the power to the projector off until it is cool enough to safely shut down.

There is really not a whole lot of advantage to wait to turn the fans on as you should have them running the entire time that the lamp is on.

Hope this helps, Good Luck with your PJ.

Hope this helps someone, I have been asking a million questions and getting help so my turn to input.... I recently saw some fan temp controllers and such but it seems that with those designs , the box remains hot ( voltage wise ) I used to be a tech at Honeywell for some years , so I figured the least I could do is supply you folks with a quick and dirt design that will let the power be off to the box and yet let the fan cool the box and bulb for till it cools down.

It requires a few parts but it is well worth it. I will be putting one in mine.
When power is on, the batteries will charge and the fan will remain on. When power is cut off , the box will be dead, the batteries will run the fan until the temp switch drops out, you can just buy two of those 4 AA battery holders and hook them together to get 12 volts , then install nicads in them. Cheap enough, also you can eliminate the Lm317 regulator because the nicads act as a regulator , you cannot over charge them really. But the regulator makes for exact voltage cause some nicads aren't happy with fluctating voltages. Any way , for what it is worth , here it is and hope it helps.
Thanks , MastahScott

Hmmm...

What happens when the NiCd batts wear out and don't hold much of a charge, there's a risk that the fans will run down and stop before adequate cooling has been achieved? My rechargeable shaver doesn't hold a charge for more than 15 secs now, I have to plug it in to use it. Seems like added complexity for a small gain. Not sure about the concern with the box being electrically hot, even with your circuit, there's still 120v (in the US) live in your box where your line cord comes in and attaches to your main switch. Everyone building a box should use proper wire nuts or terminals and make sure everthing is insulated properly against shorts. Besides, I would reach my hand in there right after I shut off the bulb anyway. Am I missing something here?

Ed

Well, you got a better idea? Lets hear it.

Good nicads, generally last at least a year if they are charged properly, most problems with nicad arise from the user who does not understand that nicads are not just any battery, they have a memory, what ever that memory is set to initially is about all the time you will get out of it. If they are treated correctly , respectively they will last and more than enough to power a fan. Further more, there is nothing complex about it. If you wish to leave your box wired hot, sobeit.
The batteries merely get the boxed cooled down after the thing is off.
I really don't think if the batteries did happen to say ,go out in a few months , that it would be a catastrophe. Might shorten the life of a bulb maybe a little or maybe not. What is the trade off? Maybe someone getting electrocuted? Not in my house they won't. You don't like nicads? Use something else for a mere 12 volts. So, tell ya what , get a lil 12 volt adapter and plug it in to the wall that will eliminate the batteries and the hi voltage. So, yeah I guess your missing something there.
This was put here for those who intended to use it maybe or even modify if needed, isnt that what the forums are for? Now then, am I missing something here? Ok , Ill add a schematic of one with a 12 volt adapter.
have fun , all is good.

Ok , here is one that you can use but this one keeps voltage up to the point of the transformer, that is to say mount the transformer near the rear close to where the power come in at , that way only one side of the transformer is really exposed which is the 12 volt side. The 120 volt side is close to the back , therefore the rest of the box is dead to 120 volt.

Then there is one more answer if you don't like that one , and that is to have 2 fans, 1 is 12 volt, the other is 120 volt . The 120 volt one is on all the time when the light is on , when you kill the box the 120 is dead. Now assuming you have the 12 adapter pluged in the jack that is installed in the box , then the other fan will come on if needed to assist the other, and will stay on after the box is off until the temp reaches cool.

Calm down, jeez.

Just asking questions, you know, a little constructive criticism?
I apologize if I hurt your feelings.

If you look at all the PLOGs and project galleries, you'll see that many do use a 12volt wall wart to power their fans. I'm leaning toward 12v fans because they tend to be quieter. Others prefer to use 120v fans with great results.

Like I said before, the wiring in the box should be insulated with proper terminals and/or wire nuts, double and triple checked. If a person doesn't have the proper respect for electricity, said person probably shouldn't be building a DIY projector and just buy a commercially available projector.

My better idea? Already been done many times by other builders, keep it simple and neat.

If the MODs wish to delete my posts, feel free to do so, won't hurt my feelings

it's all good, no hard feelings and none intended. No reason to delete anyones mods either. People are what got us here , people are what will help us and people will get us on our way. That is to say, everyones input counts, I wasn't being sarcastic or peed, I truly meant if you had a better Idea I was game, and if not . Then your opinion was well counted was all. Im sorry if I came across wrong , it was not my intention at all.
please have a good day friend and thanks for your inputs , I look forward to more. I am here because of people like you ,Brain and others because I don't know squat, just electronics to a fair extent, the rest..... well Im kinda lost.
thanks again

MastahScott

Ednigma has some good points, but I kind of like the ni-cad idea for use in case of a power outage or if you had a highly portable box(just shut it off, unplug it and go). I would be worried about relying on it regularly though, because at some point there won't be enough juice in the batteries to run the fans long enough.

Its good to have someone with electronics knowledege in the forum, perhaps you could explain the function of that bridge thing next to the 12V output on your schematic? I am competent with 120V wiring but I often get lost when looking at electronic type schematics.

Hey Death (can I call you that )

You bring up a good point about power failure. I saw someone, I think it was moose and his coffee table PJ, use a UPS to plug his PJ into so a momentary flicker of the power won't cause his bulb to turn off, in which you would have to wait a minimum time until the bulb cooled before you could restrike.

That bridge is used to rectify the AC voltage to DC to charge the batteries.

Ed

Yup, that bridge is called a full wave bridge rectifier and it is used to change the output of the transformer from 12 volts AC to 12 volts DC To run the 12 volt dc fan and to recharge the batteries when the unit itself is running and believe it or not, nicads ... if treated correctly are very very dependable and last a long time, christ , were not running a pace maker , we are merely running a little 12 volt fan for about 3 mins. Think about it.

If that isn't enough , you could add a more expensive gel cel or deep cell sealed acid battery like the UPS's have in them but a little smaller one like 1 ah. Point being , it is a simple cheap easy to use problem solver circuit for those who may want it.

ednigma,
Yes, I have one hooked up to my projector. It has actually come into play a couple of times. It's not a big ups, but when the power went out on me it gave me enough time to shut the bulb off and power the fan to cool it down.It cost me $50.00 from Staples, worth its weight compared to replacing the lcd.
Toby

Or ya know just get one of those little inverters from walmart, their like 300 watt and peak 500 watt, then just hook a car battery or motorcycle battery to it. The UPS is probably cheaper than both those but a good option if you have a battery that your not using.

OK I have been working on this for a while and have a few questions.

I have a standard computer cable that I cut the end off of and am using it as the power source for the projector. The switches I have say on them 10A 277 VAC, 20A 125 VAC...does this mean I need to hook up the 277v line on the ballast or get a different switch or get a different fuse so its 20A instead of 10A?

On the fans...Should I take the wiring that comes with the fan that's supposed to plug into the computer and use that or splice it near the base and wire it in. I tried just doing it near the base and have fried a few fans so far so thinking I need to use the computer connector...tips or pics here would be appreciated! I have the UC-12FAB-B(N)

Thanks in advance!