LEDs to blink like lightning

[mattyfab]

to whom it may concern,
i am developing a sculpture idea.
it is a plastic and metal box that will appear to have a lightning storm going on inside.

i will need to operate 5 or 6 LEDs on a
9 to 12 volt dc circuit. Each LED will be on its own set of 12" leads.

i am also looking for blue or white LEDs to do this
Can some one recomend a supplier?.

i am looking for a random or sequential controller that
will let LEDs flash in a random fashion.

i could possibly use a sequential
flasher for this sculpture, but random
would work better.

Are there IC controllers, random or sequential, that do this.

thanks

 

[ljcox]

You can buy LEDs that have an internal flashing circuit. I expect that the timing would be inexact, so the LEDs would appear to be flashing at random.

However, they may be all the same colour, so you would have to put a flasher in series with one that has the colour you want and prevent its light being seen.

 

[Dr.EM]

Generally the flashing ones are ordinary brightness ones. What you'll want are high brightness white and blue ones. I think for lightning, a strobing effect would look good, mabye alternate white then blue, very fast, and occasional pulses. So, what I think would be good is to have mabye a 14hz oscillator (555) to pulse the LEDs as a strobe, a NOT gate can give the alternate colour effect, use transistors to supply the current needed. To make the flashing random, a white noise generator is good, with a unit that samples the voltage of the waveform periodically and when it exceeds a set voltage, will trigger your LED array. I can draw a schematic for the 555 oscillator part, but i'm not certain how to go about the white noise random bit, someone else may know. I believe theres also a way of doing it with a PIC thats floating at one input :?:

 

[stevez]

To be more realistic you might want to vary the intensity of the light.

 

[ljcox]

A psuedo random sequence can be generated by a shift register with an XOR gate generating the feedback.

A 4 bit SR will give you 15 states (see https://www.electro-tech-online.com/threads/annoying-high-pitch-sound.8013/), and an 8 bit 254 states.

So a LED would be connected to each output of the SR.