Please forgive the noob, just into electronics and have maybe 12 hours under my belt.

I'm working on a project where I want a handfull (4, 5 or 6) of LEDs to flash randomly and at random intervals. I played around with a 555 timer and got the idea to do the following.

I've got 2 555's (actually a 556) pulsing at different times. One has a high pulse about every second, the 2nd about every 1.5 seconds. Each feeds into it's own binary counter (CD4520) and the outputs of the 2 binary counters power LEDs. I'll call each of these circuits A and B.

Next, I took a CD4071 OR gate and combined the outputs from the 2 circuits like so:

• The 2's position from A and 4's position from B combine to a transistor to power 1st LED
• The 2's position from B and 4's position from A combine to a transistor to power 2nd LED

Video here: http://www.biocow.com/e/ff.MOV (Long load time, sorry)

This is working out pretty well for me. I wanted the flashing to be fairly independent from each other. That is I don't always want lights turning on and off at the same time, or one turning on and the other turning off at exact same time. Sometimes is fine, but not every time.

I actually ran out of transistors and will but running out to get more so I can hook up more LEDs.

So my question for all you fine people is am I on the right track? Does anyone have suggestions on another route that would achieve the same results? That being what I'm calling "Organically" (as opposed to digitally) random flashing lights.

Thanks so much in advance for any replies. As I said, I'm just starting out and having a lot of fun with it but I'm very eager to learn more.

P.S. I don't know this forums ettiquets yet. If there is a place I should introduce myself please point it out. I didn't see anything.

Thanks.

 

Hello,

You could hang leds anti parallel between the 555's.
You will create a sort of firefly circuit that way.

Bertus

 

Fireflies is actually exactly what I'm going for. I hadn't though of just using multiple 555's. I had thought about working in the output of the 555's into the output from the counters on maybe 2 or 3 of them to make them even that more random and not in sync with each other.

I had also though about using multiple oscillators as well. I'll have to play with these 3 and will probably end up combining some different ideas. Thanks for the idea of sticking to just 555's.

 

Hello,

The frequency of the 555's will influence the behavior.
When using frequencies of abot 1 - 10 hz the leds will go on and off.
When using frequencies of around 1000 hz or more the leds will fade on and off.
Just do some experimenting to see the effects.

Bertus

 

This is the circuit I came up with...

LEDs, 555s, Flashers, and Light Chasers