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Light for a gun safe

I want to put a light in my gun safe that will come one when I open the door. Since running power into the safe is more than I want to deal with, it will have to be battery powered, I was thinking 2 to 4 AA alkalines. Four LEDs should give me the amount of light I want. I also want an automatic dimming, where the darker it is in the room the dimmer the LEDs will be. Since this is going to run on batteries, I want it to be as efficient as it can be. I went looking at data sheets and found this,

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I was thinking of putting a photo cell in parallel with a pot to get the value for Rset right Does this sound like a good plan or does someone have a better suggestion? I am just getting into electronics as a hobby so I'm not too familiar with what all is out there, I mostly just look through the Mouser and Digikey catalogs.

Also it is my understanding that they are making LED's more efficient all the time, can some one give me a good source for some of the newest most efficient LED's? I only need 4 for this project, but I have another project that will need a lot (around 100) and I don't want to spend more than I have to. Also, both run on batteries, so the more lumens per watt the better. Specifically I am looking for 5mm white, red and green with a viewing angle of 45 to 60 degrees with maybe some of the whites having a viewing angle of 30 degrees.

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Chris W

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Chris W
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Why not just keep your guns in a locking refrigerator?
Reply to
John Fields

Try this:

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With your chosen device, what were you going to do with SHDN (the PWM input)?

Reply to
John Smith

I read in sci.electronics.design that John Smith wrote (in ) about 'Light for a gun safe', on Mon, 11 Apr 2005:

He says he wants to use it for dimming, using a photocell and a resistor. But the impedances are wrong for a CdS cell. He will need to add at least a transistor (a FET would be indicated, because of the high impedance of the CdS cell at low light levels) and associated resistors to do that.

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Reply to
John Woodgate

The gun safe is also a fire safe and I keep many things other than guns in there.

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Chris W

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Reply to
Chris W

Sounds like a cool, but over-the-top application. I used to do a lot of this kind of stuff before I got old. Now, I'd just put a flashlight inside on the shelf and use the time I saved not building the light to go shooting ;-) mike

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Reply to
mike

How would I hook up the transistor to that chip? Can you recommend any part numbers with data sheets I can look at?

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Chris W

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Chris W 

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Well, in that case I suggest that you use a 7555 with one section
running as a fixed astable and the second section running like a
one-shot triggered off of the first one.  Use an LDR as the second
one\'s timing resistor in order to vary its output pulse width, and get
your dimming function by driving your LED\'s in parallel through a
2N4403 driven by the Q output of the one-shot 

Use a form "B" reed switch and a magnet to connect power to the
beastie and it only runs (draws _no_ quiescent current) when the door
is open.

Want a schematic?
Reply to
John Fields

Sure but I wold also like to know why you are suggesting this over the chip I found.

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Chris W

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Reply to
Chris W

Next to the Beer ;-)

Reply to
Frithiof Andreas Jensen 

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Your way might be the way to go, but it seems like too much of a
hassle for me.

Inductor, special caps, Schottky, 1.2MHz, ground plane, PCB layout... 

Plus you\'ve gotta order all the stuff, probably from different places,
so in the end you\'ll have spent so much on it you\'d _have_ to keep it
locked up in a safe!
Reply to
John Fields

I figured I was missing something, that there was some reason why there had to be a fixed lamp inside, and that it had to come on as the door opens.

Yes, I'd just put a good flashlight inside, maybe even putting a bit of rope on it (or chain if you want to get fancy) to attach it to the inside so it will be harder for the flashlight to go missing.

Michael

Reply to
Michael Black

I just did some checking and it looks like digikey has the parts I need and I was going to just use a Digikey PN 33206CA-ND to connect the SOT-23-6 package to a generic prototype board. I'm guessing from what you are saying it won't work very well that way, am I missing something?

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Chris W

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Reply to
Chris W 

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Not at all.  Sounds like you\'ve got it all under control. Go for it!

Matter of fact, that way is way more efficient than mine, so you ought
to get longer battery life.
Reply to
John Fields

John Fields wrote in news: snipped-for-privacy@4ax.com:

They make small battery-powered fluorescent lamps that use either 4 or 8 AA alkalines,and are meant for installation in closets where there are no power outlets.(they also have an external DC power jack for use with a wallwart) They're about $10 USD apiece.You can find them at Wal-Mart,Home Depot,or Lowes. It would be simple to install a normally open microswitch in parallel with the existing switch so the open door turns on the lamp.

Alkalines will last 2-3 years in standby.

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Reply to
Jim Yanik

Chris W wrote in news:CNz6e.282$yO2.204@lakeread07:

You could try Linear Technology's LT1932;6 parts and it will run up to 10 white LEDs from a variety of battery voltages.It's a SMD circuit,can be made very small,about the size of two pennies stacked together.(excluding the LEDs.) I made one to run 4 LEDS for a 2 AA flashlight.

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Jim Yanik
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Reply to
Jim Yanik

On Mon, 11 Apr 2005 20:48:21 -0500, Chris W wrote in Msg.

Maybe I'm off-topic because this is an *electronics* newsgroup, but what's wrong with a normally-closed microswitch mounted such that it is depressed when the door is closed? You can glue the switch to one of those crazy magnets out of a harddrive and stick that into the safe behind the door -- a non-invasive and adjustable solution.

--Daniel

Reply to
Daniel Haude

I guess I wasn't clear. I want the dimming feature because when it is dark and your eyes are adjusted to the dark you don't need as bright of a light to see with, and don't want a blinding light when you open the door. I am still planing on using a door switch of some kind to turn the thing completely off when the door is shut.

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Chris W

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Reply to
Chris W 

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Make sure the LEDs don\'t shine on the dimming sensor!
Reply to
John Fields

How about one of these?

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Cheers! Rich ------ There was a young gaucho named Bruno Who said, "There is one thing I do know, Women are fine And children devine, But the llama is numero uno."

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Rich The Newsgropup Wacko

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