Hi all,
I'm completely new to this forum, so I hope I am asking in the right area.
I'm working on building a toy for my 3 year old boy. What I am trying to do is to get 16 LEDs in a circuit to all flash independent of one another at seemingly random rates (probably in the 50-250 ms range) - to give a flickering/shimmering effect. In addition, I want to use a radial potentiometer to vary the brightness of the LEDs (as a collective) as well (i.e. as he turns the dial, the set of flickering LEDs all get brighter / dimmer together).
And to complicate matters - I want four sets of these (each with 16 LEDs and its own pot).
I'm assuming I'll need to use something like 555 timer circuit in conjunction with something.
Does anyone out there have any bright ideas as to how I might accomplish such a thing?
Thanks for any useful suggestions you might have.
P.S. This is just for a toy - it has no commercial use.
Looking for a way to get 16 LEDs to flicker at "random"
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forrest_holleman
- Posts: 1
- Joined: Tue Dec 20, 2011 8:13 pm
Re: Looking for a way to get 16 LEDs to flicker at "random"
I assume that you want each LED to constantly change its ON time and OFF time, like for example a series that goes like this?:
ON 53 ms -> OFF 227 ms -> ON 104 ms -> OFF 170 ms -> etc.
and another LED would at the same time have different time values?
This smells like white noise
ON 53 ms -> OFF 227 ms -> ON 104 ms -> OFF 170 ms -> etc.
and another LED would at the same time have different time values?
This smells like white noise
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SamRodgers
- Posts: 20
- Joined: Sat Feb 04, 2012 8:33 pm
Re: Looking for a way to get 16 LEDs to flicker at "random"
The brightness control is very simple. Connect the common rail of all LEDs to a constant current supply (transistor - zener - resistor) whose current can be varied.
The pseudo-random timing is more of a problem. I think I would start by driving 9 LEDs via a 4017 decade counter connected to run in loop mode. So far this is very simple. You could double-up on the 4017s to drive 18 LEDs in total - all with the same common rail.
Then you need to feed a "random" width pulse to the voltage rail feeding the constant current supply. Now it gets more complex. I don't have an immediate answer to this and I'm not even going to bother thinking about it unless you have a clear understanding of the suggestion so far. If you can't figure out the simple circuit, you need to go back to basics. Don't run before you can walk.
The pseudo-random timing is more of a problem. I think I would start by driving 9 LEDs via a 4017 decade counter connected to run in loop mode. So far this is very simple. You could double-up on the 4017s to drive 18 LEDs in total - all with the same common rail.
Then you need to feed a "random" width pulse to the voltage rail feeding the constant current supply. Now it gets more complex. I don't have an immediate answer to this and I'm not even going to bother thinking about it unless you have a clear understanding of the suggestion so far. If you can't figure out the simple circuit, you need to go back to basics. Don't run before you can walk.