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 Question on a simple LED project..
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By: Anonymous: yuppicide () on Wednesday, January 19 2011 @ 03:30 PM PST (Read 3656 times)  
Anonymous: yuppicide

You have a little tutorial on how to make an LED sense the dark and come on.

How would I do the opposite?

I have a project in which I've designed a video game for the Atari 2600 called Skull Island. It's a puzzle game featuring 40 levels from beginner to advanced.

It's being packaged in a wood box that is also a puzzle to open! You need to complete 20 moves in the correct order to open it!

So far I've sold about 30 pre-orders of the game.

I'd like to buy at least 30 of your Candle-Flicker LED's and have them come on when someone opens the box. They'd have to run off a battery.





       
   
By: Windell (offline) on Thursday, January 20 2011 @ 03:12 AM PST  
Windell

So, what you want to do is to leave a circuit running all the time, continuously watching for when light appears? You'd almost certainly run out of power well before anyone opens the box.

A much better idea would be to arrange some kind of a mechanical switch, that completes the circuit when the box is opened. A little "normally closed" tactile switch could do the job, keeping the circuit open (broken) while the lid is shut. It won't use any power, except when the box is open.


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By: squall_line (offline) on Thursday, January 20 2011 @ 07:11 AM PST  
squall_line

Windell-

I think the OP is referring to the all-analog "Simple and Cheap Dark-Detecting Circuit": http://www.evilmadscientist.com/article.php/nightlight.

It would take some slight re-wiring, but if one were to use a Photodiode or Phototransistor instead of a Photoresistor, one could effectively make an all-analog "Light-Detecting" circuit instead, that didn't constantly draw power (or that drew it at a minimal rate, the way the Dark-Detecting Circuit would), yes?


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By: Windell (offline) on Thursday, January 20 2011 @ 09:34 AM PST  
Windell

I think the OP is referring to the all-analog "Simple and Cheap Dark-Detecting Circuit": http://www.evilmadscientist.com/article.php/nightlight.

It would take some slight re-wiring, but if one were to use a Photodiode or Phototransistor instead of a Photoresistor, one could effectively make an all-analog "Light-Detecting" circuit instead, that didn't constantly draw power (or that drew it at a minimal rate, the way the Dark-Detecting Circuit would), yes?

So I presume as well. And yes, you can build a similar circuit without the inverter.

But, those are *not* going to be the kind of super micropower circuits that can last for months until someone opens the box. It's probably possible to design something like this with a photodiode that gradually biases a low-leakage MOSFET, but (1) it would require some care and (2) it wouldn't actually be a similar circuit. In any case, using the "switch" technique *is* superefficient, and could allow the box to stay closed for *years,* even with only a single coin cell hidden inside.


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By: Anonymous: yuppicide () on Friday, January 21 2011 @ 06:50 PM PST  
Anonymous: yuppicide

Thanks for the reply. You are totally right that the power would die and that a switch is a better way to go.

I'll tell you my plans. I designed an Atari 2600 puzzle game. You know how normal games come packaged in a plastic case? My limited edition version is being packaged in a real hand made wood case! Nobody has ever done this before. I'm guessing in the end it'll be more of a "show piece" because people wouldn't want to damage it, but whatever still cool.

So, anyway, the game will be packaged in a wood box that is also a puzzle to open. You need to do 20 moves in order to open it.

I'm getting at least 30 of these puzzle boxes:

https://myerscrafts.com/Tik-Tak-Tok.html

I am thinking since the cartridge is smaller than the inner dimensions of the puzzle box, I'll get some of this:

http://www.uline.com/Product/Detail/S-15324/Anti-Static-Foam/24-24-2-Anti-Static-Pick-&-Pack-Foam-Sheets

Cut them to make the cartridge fit nice and snug.

Then I got the idea that the box should light up when opened..

Problem is it needs to be inexpensive as I've only charged people $25 for the wooden boxes.. that means, the box cost me $15.49 each + shipping, glue, paint, the foam, maybe some sandpaper.





       
   
By: yuppicide (offline) on Friday, January 21 2011 @ 07:06 PM PST  
yuppicide

Went ahead and signed up here so I'm no longer anonymous. Thought I had an account here, but I probably just originally inquired about Eggbot.


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