Electronics Application Question -- Symmetrical Analog Clock Project

[aquadump]

A few years ago, I noticed that analog watch and clock advertisements mostly consist of the object at the time 10:10. In a search, I found that this was the most aesthetically pleasing time of the day, from a marketing perspective mainly because of the symmetry.
That eventually led me to calculate all of the symmetrical times of the day.
Since then, I've always wanted to take this one step farther by making what I call "functional art." That is, I would like to create a wall clock that lights a perimeter of neon or LED lights when the second hand bisects the hour and minute hands. And this is where my education/knowledge lacks.
Can someone suggest a method for me to accomplish this? I think the more robust solution would be some how making contacts for the hand intersections, to power the envisioned perimeter lights. However, since I have all the calculations done I am also interested in programming the times, but again I don't know where to start.

[Matthew]

I don't dabble much in electronics but you could also consider the golden ratio (approx. 1.618) in the artistic design if you are interested in perfect symmetries.

[jacob]

So I presume you want 60 LEDs around the clock?
Or do you want to put a led on the second hand and just have it light up whenever it passes the minute and hour hands?
The electronics part is simple. All you need is a resistor in line with the LED to ensure that it doesn't draw infinite power (and pops). Or you can have a transistor (547) trigger it.
The wiring will be a mess.
You could do in the following ways and possible others

1) As you suggest, when the hands touch each other.

2) When the hands are over the same general area of the dial.

3) You could do the wiring behind the dial on cogs (called wheels). Even electric clocks will have a gear train of the 60/60/12 variety.

4) You could have two synchronized clocks and dedicate the other one to running the LEDs. That could hide a lot of the wiring.

[Steve Austin]

rePete, share your code used to generate the Times of Symmetry table you uploaded?

[jacob]

Maybe I didn't understand it clearly. At 1:10, do you want all leds between 10 and 2 o'clock to light up when the second hand hits 12?
Also, do you only want this to happen when the hour and minute hands are separated by 4 hours of arc or whenever the second hand is right in the middle between them (which will happen every time it goes around)?

[aquadump]

@Steve Austin Here is the algorithm and the spreadsheet. I made this before Google Docs didn't suck. I think the actual calculations are on an old work computer's HD that is long gone.
@jacob 60 LEDs seems like a reasonable approach. I am interested in having the perimeter lit 2 times every minute, with a 1 second duration each time.

[jacob]

Why 2 times? Sticking with the original example of 10:10, when and what do you want illuminated?
10 to 2 at 12?

2 to 10 at 6?

[aquadump]

[jacob]

Okay, I have a mechanical/analog solution. It's complicated; comparable to building an electric motor.
You need three disks to run the wiring for the three hands. The disks should run on top of each other. The minute disk is on top, the second hand disk is in the middle and the hour is on the bottom.
Hour disk - this will have two contacts 2 hours away from the hand on either side. These contacts should be "slightly offset to one side".
Minute disk - this will have two contacts 2 hours away from the hand on either side. These contacts should be "slightly offset to the other side".
Second disk - this will have a single point of contact which will close the circuit of the offset contacts from the two other disks. This happens when the hour and minute are 4 hours apart and the second is in the middle. Clear?
The circuit is run by connecting the contact point to the perimeter. All the leds are connected in serial in a circle---you just need to hit the wires/contact points in the part of the perimeter you want. You can carry the properly sized resistor on the disk.
To do the obtuse angle, run a similar system with the contact points 4 hours to either side. You can reuse the disks. This system should use a resistor 2 times smaller, since it's illuminating twice as many leds.

[aquadump]

Thanks!
Pardon my ignorance. What is a disk? How do I physically get the power from a wire onto the moving hands?

[jacob]

Disk, disc, ... a flat cylindrical object.
If you think of it as a bicycle wheel where one of the spokes is the hand, all you need is actually 4 hours of rim. It's probably more mechanically stable to just get a disc and mount the wiring on that.
To get electricity to flow between moving/rotating parts, you need a copper brush. See link for ideas.
http://en.wikipedia.org/wiki/Commutator ... nstruction

[aquadump]

Ah, like a drill motor. I should've known that. . .