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LED/light sequencing circuit

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geoffrito

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Hi everyone. I'm new, both here and to the whole electronics field in general. That is to say, a great majority of my crude circuits have ended in failure. Anyway, I had another overambitious idea for a school project- I was hoping to use LEDs or some other form of small incandescent light to represent the moving electrons of an atom. Specifically, a carbon atom, which would require six 'electrons' being lighted at any one time- 4 in one level, 2 in the one below it.

So, basically, I would ideally like two rings of LEDs or aforementioned 'other' lights, wired such that four evenly spaced lights would be on in the outer ring, and two in the inner ring, and such that these lights would turn off as their neighbors turned on, making the lights appear to move around the circle.

Keep in mind i have barely any knowledge of electronics outside of elemental basics (forgive me)- would this be feasible or particularly complex? Hopefully not- I'd much appreciate it if any could provide some schematics.

thanks in advance : )
 
This sounds reasonably easy to do, but before we get into that, my initial reaction to your question was to wonder if you atomic model is entirely appropriate. My understanding was that the Bohr model, which your project seems to represent, has been obsolete for years and years, but then I read this in Wikipedia:

" Introduced by Niels Bohr in 1913, the model's key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen; while the Rydberg formula had been known experimentally, it did not gain a theoretical underpinning until the Bohr model was introduced. Not only did the Bohr model explain the reason for the structure of the Rydberg formula, but it provided a justification for its empirical results in terms of fundamental physical constants.
The Bohr model is a primitive model of the hydrogen atom. As a theory, it can be derived as a first-order approximation of the hydrogen atom using the broader and much more accurate quantum mechanics, and thus may be considered to be an obsolete scientific theory. However, because of its simplicity, and its correct results for selected systems (see below for application), the Bohr model is still commonly taught to introduce students to quantum mechanics, before moving on to the more accurate but more complex valence shell atom. "

So if you intention is to teach youngsters, then let's get to it.
 
So, what you describe is two rings of lamps (LEDs are quite appropriate for this). In the outer ring, I'm not sure how many lamps you have, but there are four equally spaced ones on at a time and the lamps "chase" around in a circle. In the inner ring there are half as many, and they "chase" around in a circle too. Is that right? Is there any relationship in timing between the inner ones and the outer ones?

The basic setup to get this to work would be to start with an oscillator (based on 4000 or 74HC logic) that outputs a frequency equal to the rate at which you want the LEDs to chase around the circle. Say, 5 Hz? Now, feed that oscillator into a decade counter chip, like a 4518. Next, feed the four bits of the counter chip to a 1-of-10 decoder chip like the 4028. There are ten outputs of this chip. What you should get when its all wired up right is that each of the ten outputs turns on, then off, in sequenc, and there are never more than one on at a time. All you need to do now is wire up each of the outputs to a group of 4 leds in your circle and wire them in order.

Now, having rememberd just now that you don't have much experience in getting electronics to work, we will need to develop a schematic. Want to try your hand at that first?
 
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Yes, thats pretty much what I had in mind for this. in terms of where any given electron in the inner level would be in relation to one in the outer level, no, it doesn't really matter much. I dont have any particular preference in terms of how many LEDs total would be in each ring, so long as there is some appearance of movement as they 'chase' each other around.

I think I get the gist of what you're saying here, but as for schematics...ha! I've never had any particular aptitude for schematics. If you or anyone else wouldn't mind too much.... :eek: much appreciated
:)
 
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