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-   -   If I only had a Brain! (http://www.diyaudio.com/forums/diy-projectors/62055-if-i-only-had-brain.html)

Luca Brazzi 5th August 2005 05:44 PM

If I only had a Brain!
 
Well... I have a nice working DIY projector... (actually its more of a first time through testbed/prototype) It uses the Lumen Lab standard lens set, a 250 watt DE HQI bulb with an IKEA Napkin Ring Reflector, and a BenQ 567 LCD monitor...

It works great! Im happy with its performance (although I scratched my LCD/Fresnels building/rebuilding it about 50 times to get it right... oh well)

Now for the next thing...

One thing missing from our DIY projectors that Ive noticed is... for the most part... they lack some basic intelligence that commercial projectors have.

What do I mean?

Well... a commercial projector has some basic built in intelligence that allows it to "understand" a few things about its operation. First off... if you shut off a commercial projectors power... it knows to let the fans run for a while to help cool down the bulb... it also knows that if you try to power back on too soon not to turn on the bulb, etc....

Ive been considering starting a project to develop similar features for DIY projectors, but would like some input as to what other functionality would be desired?

Incorporate temp sensing maybe?
Dont allow the light to come on unless the fans are running?
Automatic fanspeed control?

Heres one... how about an auto off after X hours if there is no intervention (for those of you who fall asleep with the projector running)

Luca Brazzi 5th August 2005 09:38 PM

How about a Bulb Life counter that tells how many minutes/hours the bulb has been lit?

Stocker 6th August 2005 12:06 AM

A standard hour-meter is simple enough for the bulb life.

The fans running with the bulb should also be very simple.

As for the fans running after shutoff, that could be a simple R/C time constant and a little logic. Nothing magic here, but perhaps a cut above the average DIY job.

Go for it. I suggest starting a new thread in the appropriate forums for each question so some of your questions don't get lost in the discussion of the others.

Luca Brazzi 6th August 2005 02:10 AM

What Im trying to do is to get a holistic view of the entire system. That, I think would best occur from projector building folks...

Quote:

As for the fans running after shutoff, that could be a simple R/C time constant and a little logic
True... when you think of individual functions they are each relatively simple, until they start adding up. Then trying to get a completely integrated solution becomes more difficult, and the circuitry far more complex if individual control circuits/discreet logic circuits are involved. Like the fans running after power shutoff as you said is a simple RC time constant, but what happens if you want to also ensure that your lamp doesnt come on if your fans arent running? Then add fan speed adjustment based on temp, etc.

Im thinking along the lines of a microcontroller based design with all the logic embedded. Take a microcontroller, stick on some sensors/mosfets/etc. and write the code to monitor/control everything...

mbates14 6th August 2005 02:42 AM

suggestion.

go with a pic. like a PIC16CF84 or something like that.

get some books, or online manuals and learn how to program one.

That will solve all your little needs. hour counter LCD on the side maybe, use portB to drive the relays to control the fans, ballast, yadda yadda. and have port A to drive an LCD, or temp sensors.

and use the LCD as a status display. Hell, you can find premade code to read write ports, use LCDs and all that stuff.

Im using a PIC a friend programmed for me to control my ice machine.

The thermostat and timer went bad, so we programmed a PIC to run the cycles and temperature sensors (reverse-biased diodes).

Sorry, kinda off topic. :smash:

Luca Brazzi 6th August 2005 03:19 AM

Quote:

go with a pic. like a PIC16CF84 or something like that.
Yes...

Ive been programming PICS for many years...thats why Ive been thinking this could probably work... Im trying to gather suggestions on possible features based on different projector designs/experiences/etc....

I think something like this could be especially helpful in those designs (most of the ones Ive seen) that use Computer fans for cooling.... computer fans are NOTORIOUSLY unreliable if they get too much dust in them... if you embed a computer fan inside your projector where you cant see it spinning... how do you know if its really running? Maybe the bearings are shot/etc and its drawing current but not spinning (just jittering) I guess an indicator light could give you a clue but then thats yet ANOTHER dedicated circuit if the individual control circuit choice is used over a controller.

What I would like to get to is a total control system. When I push the on/off button, the controller takes over and turns on the appropriate projector subsystems if the correct parameters are met, if something go wacky... It sets off an alarm/shuts down/etc

Question: If you had a choice for a Bulb Usage timer would you rather

A) Have a timer that measured the time the projector was on
B) Have a timer that measured the time that Electricity was applied to the Ballast
C) Have a timer that measured the time that the bulb was actually producing light

cbm5 6th August 2005 04:01 AM

If someone came up with a preprogrammed microcontroller, then hey, some of the more obsessive among DIYers might invest the extra expense and effort and debugging time. But most of us realize that we're not going to get a projector with all the bells and whistles, we'll just get a cheap projector. It's easy enough to remember to turn off the fan sometime after you turn off the light, and it's no major loss other than a few cents of power to leave the light on a couple extra hours. The only thing that could possibly damage an expensive component is the fan failure that results in a damaged LCD, and there are readily available products to monitor temperature and control fans. http://www.crazypc.com/Merchant2/mer...uct_Code=5220B

If you want to go all out, then no one's going to stop you...but DIY projectors have been around for years, microcontrollers have been around longer, and we haven't really seen many people make a controller. I'd say that if it was necessary, it would already be common.

Luca Brazzi 6th August 2005 05:11 AM

Quote:

Originally posted by cbm5
If someone came up with a preprogrammed microcontroller, then hey, some of the more obsessive among DIYers might invest the extra expense and effort and debugging time. But most of us realize that we're not going to get a projector with all the bells and whistles, we'll just get a cheap projector. It's easy enough to remember to turn off the fan sometime after you turn off the light, and it's no major loss other than a few cents of power to leave the light on a couple extra hours. The only thing that could possibly damage an expensive component is the fan failure that results in a damaged LCD, and there are readily available products to monitor temperature and control fans. http://www.crazypc.com/Merchant2/mer...uct_Code=5220B

If you want to go all out, then no one's going to stop you...but DIY projectors have been around for years, microcontrollers have been around longer, and we haven't really seen many people make a controller. I'd say that if it was necessary, it would already be common.


Very true...

The more I talk to folks... the more I realize.

What about this...

What if you could embed a controller into your projector that solved one simple problem?

For example... I was sitting in front of my PJ typing my last post, and listening to music on the PC I have hooked to it... Then... I realized I needed to go to the store to get cigarettes, and I said to myself... I WILL NOT leave the house if even for a minute with that projector running because who knows what will happen between the time I leave and the time I get back to turn it off? Its kinda like the IRON.... nowadays you dont have to worry about leaving your IRON on because someone embedded a timer in it so if it sits unused for X amount of time... it turns off by itself (unless you have a REALLY old IRON). Now... someone may say, "Well then just put a Timer on the Projector" and again Id say... "True.... that will work...very well... but when you start to try to add something that is more than simple on/off it gets complicated"

Luca Brazzi 6th August 2005 05:26 AM

Ive GOT IT!!!!

Thanks folks!!!

What Im going to do is design the controller to use a motion detector as the "Reset" for the projector staying on! If there is no motion in the room for 2 hours... the projector will turn off.

Of course Ill use a Pet Sensitive Alarm system motion detector... I wouldnt want the pooch walking around when Im not here to keep the projector running...

CCMCornell 6th August 2005 05:53 AM

Why not just get that Honda robot to tend to the projector while you're at it? Or, you could try B-4, Data's (from Star Trek) surviving brother. He's kinda stupid, but I think he could handle it! :D

But seriously, your ideas are great and it's fortunate that you have PIC programming experience. PIC programming and even embedded Linux devices are things I've always wanted to start learning to add to my DIY capabilities. Maybe you'll share some tips for us inexperienced peeps when the time comes?


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