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.

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.

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?

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.

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.

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.