Random LEDs, random time on/off?

[bobleny]

I have 64 LEDs aligned in an 8 by 8 square, I want to create a circut that will choose a random number of LEDs, random LEDs, and a random length of time off/on.

Basiclly, it's a random light show. I don't have room to play with either, so it's quite difficult.

Any one know a good way to do this?

My electronics instructor suggested a random number generator to produce random numbers, then some sort of circut to use that number. There must be a better way.......

Thanks!

[bobleny]

Wow, No ideas?

How about we start small?

How do I create a circut that can select a random LED?

There, that should be easier to answer...

Thanks!

[OnOff]

You can use a microcontroller and program it to generate a random number.

If you are saying that you have an 8x8 square of LEDs an ATtiny2313 would be fine or ATmega8 if you want to have more free pins to do fancy thing with them.

I hope this gives you a clue, if more help is needed just tell me.

[bobleny]

Do you have any information on these chips? I never used them, I'm affraid the only chip I've used was a N555 timer.

[idevices]

How do your LEDs need to illuminate? e.g. fast on-off, fade on/off...

[bobleny]

Ah, fast on off. Me and my teacher came up with the idea of using a bunch of N555 timers with different frequencies. Each timer will control 2 LEDs. So when the signal is positive, the one LED is on and when the signal is negative, another LED is on. Using different frequencies allows for random lights. Now, of course, this isn't really random but it will suffice.

But any other ideas or suggestions would be greatly appreciated.

Thanks!

[OnOff]

If you are not familiar with micro controllers, then the 555 timer will be a good solution, but your idea states that each timer will drive 2 LEDs so you need 32 timers (WAW, a very large and mesy board), so there are two solutions:

1- Use a micro controller (ATtiny2313 as I suggested before) if you know how to program one. And the board will be simple and prety. The datasheet of this uCont. is found onthe Atmel's web site "www.atmel.com"

2- Or use two 8bit counters and two 8bit buffers (or one 16bit) and a timer, but in this case YOU have to connect the LEDs to the counters in such a way that when they count (up or down) the LEDs will look like switching randomly. The timer will drive the counters and you can use a variable res. to play with the speed of switching.

[idevices]

Yes, 32 timers is about 31 too much!

[steven]

:)this is easy in the forums here , i posted a 10 led light chasser circuit some time ago and from these ten leds they are linked to another ten leds and so on there was 96 leds total which i dident post the whole circuit just the ten led light chasser details but to make them stop as to use them as a random number generator or in my case a lotto number picker i just tap a wire to each side of the electrolytic capacitor and then run it to a switch so when i press the switch the leds all stop in there tracks , then i use the on/off switch to switch it off then back on again to get them moveing , they looked like ten leds chaseing each other at the same time so i get to choose 6 numbers. out of ten when they stop, looking at 1 led moveing along if you follow it with your eyes it makes some kind of optical illiusion to  so you think your seeing double

[bobleny]

Hmmm... Glad you brought this up. I can't believe I didn't show you... I could have sworn I did! I know I did in another topic. I wonder what you guys think of this. I drew this up some time in october. I think It will display a seemingly random light pattern.



I'm considering a micro controller instead.....