Circuit Design Help/Schematics Needed

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Can't see a need for a timer ,soft start, or incandescents. The ones I've seen are just a big bank of flourescent tubes (about 10 off 80watt tubes, c/w anti-glare panel) to sit in front of. The tube phoshors -must- be a matched 'daylight' colour, having a strong bluish tinge. A little uncommon but available from specialist sources. regards john

Reply to
john jardine
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Hi all,

I am trying to find a circuit that will allow me to automatically dim an incandescent load (i.e. reduce voltage from 100% to 0%) over a preset time period (say 30 minutes) and also bring the load back up to full power (i.e increase voltage from 0% to 100%) over the same time period. I need both of these actions to be able to be timer controlled, or triggered when an input goes high (e.g. one input for each function). I want to use the circuit to run a dawn/dusk simulator (two 240v AC daylight simulation bulbs) for use in the treatment of SAD (Seasonal Affective Disorder). There are commercially designed/built models available - but these are a bit too overpriced for my liking.

Any help/suggestions that anyone could offer would be greatly appreciated as I've had a google and am unable to find anything of much practical value (however the only slight problem I have is that my electronics knowledge is only up to GCSE level, but I'm sure I could manage something a little more complex if push came to shove!)

Many thanks

Dan Ricketts

Reply to
Dan Ricketts

Hi John,

Thanks for your reply. What you are thinking of are light boxes (that's the next thing I'm planning to build). The idea behind the dawn/dusk simulator is that it simulates the rising/setting of the sun, which is supposed to be particularly helpful in cases of SAD (you wake up to the slow 'rising' of a light source instead of waking in the dark - which I have to given my job).

Many thanks

Dan

Reply to
Dan Ricketts

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My apologies. I only saw the top half of the post. Read it all now and have the context. regards john

Reply to
john jardine

X10 dimmer module?

John

Reply to
John Larkin

Hi Dan,

Look at the X-10 stuff. You can do almost anything with it. The basic kits mostly contain the controller that can be set to perform a certain dim and brighten sequence. If you have to record other things such as snoring levels etc. you might want to control it from a PC which can also be done through that powerline interface. The software comes with it or can be downloaded.

The dimmable modules are called 'lamp module'. They retail around $10-$15 a pop. The whole setup probably won't even cost you $100.

Just don't use X-10 for any critical tasks because the old X-10 AM protocol is not very reliable, expecially not over long distances or across phases.

Regards, Joerg

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Reply to
Joerg

Other people have suggested X.10. If you go this way, I'd watch the maximum power requirements; most of those dimmers are designed for lamps. I'm guessing your daylight simulation bulb is a halogen, or something similar. That may require more current than these little dimmers can take. Also, you probably are going to have to do some programming yourself to get them to dim over a 30 minute period.

If you know how to program, and you can't get an X.10 dimmer that has a big enough current capability, you might be able to replace it's triac with one that can handle more current. However, watch the current required for triggering, since different triacs have different requirements, and a circuit designed to trigger one triac may not be able to trigger another one. Extra heat may also be a concern, although triacs don't typically have a problem with this, since they trigger fast.

I would personally use a microcontroller to control a big triac. However, I already have the setup, and know how to program them. If you don't know this stuff, it'll take time to figure out. The basic stamp is another way to go that may require less startup time (but which will be more expensive than a simple microcontroller).

Another option would be some kind of analog timer circuit, controlled by a ramp voltage. However, an accurate ramp over 30 minutes, while not impossible, seems kinda hard to me without leakage compensation and stuff like that. One of the analog geniuses might come up with something like this for you.

There is also the low-tech solution, which is to buy a dimmer that can handle the current at the hardware store (if you can find one), and use some kind of mechanical arrangement, like a clock, to turn it slowly. Since you'll need to sit in front of the light, starting and stopping it doesn't have to be automatic. Reversing directions might be a challenge.

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   Robert Monsen
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Reply to
Robert Monsen

Check the X10 site for "firecracker" It's a kit with a computer interface and control module. Most of the SAD lights I've seen have been fluorescent. Most of 'em can't be dimmed at all. Most of the X10 stuff won't dim a fluorescent either. You might have to go with some kind of mechanical variable shutter or tilting of the whole panel.

FWIW, I went thru the SAD light stuff with a former girlfriend. SAD is a psychological ailment. She was CONVINCED...make that ADAMANT... that a $20 homemade light could NOT POSSIBLY work. Had to be the $800 commercial lamp. $800 later, she was just as "wacked out" as before. What we won't go thru for a woman. But I digress...

I'd use a firecracker to dim an incandescent then turn on the SAD light with an appliance module when it gets to be "sun up". Early morning light is kinda orange anyway.

Put a big sticker on the front that says, "Approved by the institute for SAD research".

The sticker will be the most effective part of the treatment. mike

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500MHz Tek DSOscilloscope TDS540 $2200
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Reply to
mike

Go to your local Home Improvement store and ask for a sex light. They do exactly what you say.

Cheers! Rich

Reply to
Rich The Philosophizer

Regardless of the light source you need to maintain the color temperature of the source to get the benefits of the spectrum. If you dim a halogen source you will lower its color temperature and spectral output.

What you are really trying to do is get the body to reduce the production of Melatonin and increase the production of seratonin primarily via the optic nerve. Both are triggered by the absence or presence of full spectrum or at minimum photopic light.

If I were doing this I would go with the Tube type lamps and build a simple shutter over the lamp housing. Many window blinds can be operated by a remote control gear reduced DC motor. Put a timer on the motor and a couple limit switches, viola full color temperature variable apertured lighting source.

You might wish to take a natural supplement like raw adrenal gland to aid in energy level which inherently affects mood.

Reply to
Product developer

Viola? What's the difference between a viola and a violin? The viola burns longer. ;-)

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Raw? Just eat the whole pig. ;-)

Reply to
Watson A.Name - "Watt Sun, th

"Dan Ricketts" a écrit dans le message de news: pwRjd.441$ snipped-for-privacy@newsfe2-gui.ntli.net...

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Hi Dan

I've exactly what you need. It's build around a PIC 16F873 processor. I could send you schemos and even PCB along with the programmed PIC. THIS IS NOT A COMMERCIAL OFFER. Mail me direct.

Yves.

Reply to
Yves

That was hilarious. My favorite, being a footballer = What is the range of a Viola? As far as you can kick it.

What if he's Jewish or Arab? :0

Reply to
Product developer

I adopted (and modified) one of these a while back. Perfect pitch: Throwing a rapper's microphone into a dumpster without hitting the rim.

Reply to
JeffM

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