[help] Random LED generator - Tilted Forum Project Discussion Community

FloydianOne · 12-28-2005, 12:46 PM

Im trying to help a friend who is trying to help his sister create a 2-LED random flashing "fireplace", basically he is using 2 led's that go on and off randomly to simulate the flickering of a fire, his sister is using it for some architecture project.

My question is, do you guys know of an available IC, that will easily create the randomness to light up the led's? I was hoping I could just tell him to go buy a part from radio shack or the like... However if you guys know a way to build one of these that would be cool too.

Thanks for any help!

edit: Just noticed another thread that is similar to this one, however its alittle above my head. So if someone could possibly simplify it for just 2 leds, i would be very appreciative... thanks

1010011010 · 12-28-2005, 05:05 PM

Use some Zener diodes loaded near their breakdown voltage as a noise source.

FloydianOne · 12-28-2005, 09:35 PM

That sound interesting, could you possibly draw a very simple schematic so I know how to set it up? Thanks again

flat5 · 12-29-2005, 06:48 PM

Another approach might be to use cmos gates to set up four oscillators. Schmitt triggers could be used.
Nand the output of two of them to drive an LED.
Do the same with the other pair.

Some osc. info:
http://www.web-ee.com/primers/files/WebEE/AN-118.pdf

Some gate info:
http://www.play-hookey.com/digital/e...mos_gates.html

Some LED info (just enough):
http://ourworld.compuserve.com/homep...t/elect112.htm

More LED info and good reading:
http://www.iguanalabs.com/1stled.htm

1010011010 · 12-30-2005, 12:38 PM

Quote:

Originally Posted by FloydianOne

That sound interesting, could you possibly draw a very simple schematic so I know how to set it up? Thanks again

Source ----> Diode ----> Sink

The fun part is where you figure out how to convert the noise to LED flashy flashy. There are all sorts of ways to do that and one or another website can give examples.

Keep in mind that many of the RNG/REG circuits are aimed at making cryptographically secure randomness... so there's some fancy stuff going on to minimize bias or make the signal cleaner for use in a computer. You just want to make a couple LEDs look like simulated firelight.

You may be able to use the noise directly. You may need to stuff some transistors in there to drive the LEDS. You may need some capacitors to mess with timing. Get out the soldering iron and see what works.

12-28-2005, 12:46 PM	#1 (permalink)
FloydianOne Crazy	[help] Random LED generator Im trying to help a friend who is trying to help his sister create a 2-LED random flashing "fireplace", basically he is using 2 led's that go on and off randomly to simulate the flickering of a fire, his sister is using it for some architecture project. My question is, do you guys know of an available IC, that will easily create the randomness to light up the led's? I was hoping I could just tell him to go buy a part from radio shack or the like... However if you guys know a way to build one of these that would be cool too. Thanks for any help! edit: Just noticed another thread that is similar to this one, however its alittle above my head. So if someone could possibly simplify it for just 2 leds, i would be very appreciative... thanks __________________ Fight apathy! ..... or dont. Last edited by FloydianOne; 12-28-2005 at 12:51 PM..

12-28-2005, 05:05 PM	#2 (permalink)
1010011010 Psycho Location: Virginia Beach, VA	Use some Zener diodes loaded near their breakdown voltage as a noise source. __________________ *Simple Machines in Higher Dimensions* Last edited by 1010011010; 12-28-2005 at 05:09 PM.. Reason: Spelling

12-28-2005, 09:35 PM	#3 (permalink)
FloydianOne Crazy	That sound interesting, could you possibly draw a very simple schematic so I know how to set it up? Thanks again __________________ Fight apathy! ..... or dont.

12-29-2005, 06:48 PM	#4 (permalink)
flat5 Very Insignificant Pawn Location: Amsterdam, NL	Another approach might be to use cmos gates to set up four oscillators. Schmitt triggers could be used. Nand the output of two of them to drive an LED. Do the same with the other pair. Some osc. info: http://www.web-ee.com/primers/files/WebEE/AN-118.pdf Some gate info: http://www.play-hookey.com/digital/e...mos_gates.html Some LED info (just enough): http://ourworld.compuserve.com/homep...t/elect112.htm More LED info and good reading: http://www.iguanalabs.com/1stled.htm Last edited by flat5; 12-29-2005 at 07:20 PM..