Programmable LED board (Large)

[TOONCES]

Ok so I'm going to start this by saying I'm a mechanical engineer and circuits don't make very much sense to me. (So your help is very appreciated)

I'm currently designing a board game and I need to be able to program a large amount of led's.

Basically, I have 217 holes in a gameboard that need to be able to illuminate red, green, and blue (and potentially one other color). The board is about 15"x20". The holes are 0.6" in diameter. My main objective is to have multiple different patterns programmed into some type of CPU (i.e. arduino board). So, for example, I may want to have 3 random holes lit up blue, 2 lit up green, and 5 red. This would be one pattern and I need to have multiple. Each hole has to be able to display each color (217 holes).

Now, as I mentioned before, my circuit skills are horrendous.
I need to know a couple things:
-Is there a better way of implementing that many lights into my board?
If not,
-Can someone give me an example on how to connect all these leds together so that I am still able to connect them to a CPU?
-Btw, I really have no clue how to build a simple, single led circuit.
-Should I make a PCB to connect all these leds together?
-How much power am I going to need (or how do I figure out how much power I need) in order to power the leds and the CPU?


That's all I can think of right now as far as questions are concerned. I really appreciate any help.

As a last note, I have researched online on how to do something like this but have come up with lackluster results (maybe I don't know what I'm looking for). I should also mention that I haven't really searched the forum for any previous cases because I feel that this is a unique case.

Thanks for any help

 

[schip666!]

Oh boy...if you have truly never connected an LED to a battery (!through a resistor!) you are probably biting off more than you can chew here. Perhaps there is someone in your neighborhood who can walk you though what you need? Designing this all online and ad-hoc will probably be asymptotic to impossible.

That said, my glib answers -- presuming that I understand that what you want is to be able to light up any or all of 4 LEDs in 217 positions -- follow:

Your main trouble is that you won't find a micro-controller with, hmm, 4x217=868 individual output lines.

So I would use a scanned matrix driver such that both the "plus" power and "minus" ground connections are switched in rapid succession -- this is how most multi-led displays are driven when you get to the bottom of the stack. A 15x15 matrix would drive 225 LEDs, e.g., by switching on each set of 15 in a column and enabling each column by switching on each row in sequence. (I'll bet that makes no sense, but I can't think of how to describe it better without drawing pictures...). You'll need four of those, one for each LED color.

With all those wires I recommend coming up with some kind of modular circuit board to hold and connect sets of LEDs, and interconnect the boards as well.

How many LEDs are ON at once? You can figure about 20mA per LED if it's on continuously but can spread that over your 15 matrix rows since they will be flashing at a high rate. If you were to have all 15 in a column ON that would be .3amps per color.

Or else you could use a video monitor instead? Then all your "LEDs" are already wired up...

 

[TOONCES]

Well I have actually connected an led to a breadboard before, but it has been awhile.

I'm not sure what the scanned matrix driver that you refer to is, and I haven't been able to find anything online about them. If you could direct me to some information about them that would be great. Also, would I be able to program multiple different patterns into the matrix driver?

There wouldn't be more than 20 leds on at a time, but I'm thinking if this led plan is a bad route then it won't matter much. And if it is I should be able to figure out a power required.

As far as the monitor is concerned, do you mean an actual video monitor, like computer monitor? That may be either too big or out of my budget. However, I do like the idea of having some sort of monitor underneath the board as opposed to the leds. It definitely gives more options. Is there another type of monitor I can use that would be thin/lightweight? I doesn't need to be high def or anything like that, so maybe there is a cheap screen that I would be able to use?

Thanks again!

 

[schip666!]

I just googled "matrix led driver" and got a bunch of (possibly) useful links, e.g.:
http://picprojects.org.uk/projects/lc/index.htm
http://www.instructables.com/id/LED-matrix-using-shift-registers/

The former has a brief description of the matrix drive idea. The latter has a (maybe) better method than I was thinking, to use shift registers to get the data out to the matrix. Hopefully you'll get some ideas from this.

For video... a year and a half ago I bought a used PC with a 17" LCD monitor for $180
(including a usable laser printer!). At .10 each you are going to spend close to $90 on LEDs. Maybe a reconceptualization of design criteria is in order?