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### Topic: Some help with 8x8x8 LED matrix. (Read 2371 times)previous topic - next topic

#### wmfmd

##### Dec 27, 2006, 03:57 pmLast Edit: Dec 27, 2006, 03:58 pm by wmfmd Reason: 1
Hey guys,

You can check the progress of my LED matrix here. http://www.alexcicciu.com/blog/lightmatrix3.html

So far I have 16 wires hooking it up, 8 coming from the bottom of the grid, and 8 coming from the side.

What I'm wondering is, as I start to build upwards, is there a way of connecting the cathodes/anodes to the layer underneath - so I don't need the wires coming out of the sides? I've been trying to figure it out in my head, but alas my brain is not functioning properly this afternoon.

Cheers,

Alex

#### wmfmd

#1
##### Dec 27, 2006, 04:00 pm
Also, I'm currently using bi-color LEDs - anyone know of a way to isolate just one color? At the moment they flick between red/green, but it'd be nice to turn them on/off independently. Maybe a diode?

Cheers.

#### intercranial

#2
##### Dec 28, 2006, 02:50 amLast Edit: Dec 28, 2006, 02:56 am by intercranial Reason: 1
You can put 1 diode( a real diode not a led) between your maxim chip and each column line or between each row line and it will disable one of the colours.

Since I'm not sure of your exact wiring, I would suggest that you put 1 diode in series between your maxim chip and 1 of the column lines and see which colour gets disabled. If it is not what you want, flip the orientation of the added diode. That should get you there.

#### macsimski

#3
##### Dec 28, 2006, 10:10 pm
hello there,

nice setup for some 3d!

my question is why you need to connect the layers to each other. I assume that every layer gets its own maxim chip? and the maxim chips are connected to the arduino?
--
"We're all in this together..."

#### wmfmd

#4
##### Dec 29, 2006, 11:11 pm
yes, that's right - but at the moment there are 16 wires connected to each maxim chip - if you look at some of the other LED matrix cubes, the layers are all connected together, I'm not sure how this is achieved though.

Any idea?

Thanks

Alex

#### intercranial

#5
##### Dec 30, 2006, 08:08 am
Here's a couple of pics of some other cube interconnects

http://mocoloco.com/archives/000588.php
http://www.lomont.org/Projects/LEDCube/LEDCube2.php

Are you planning a base of some kind? You could just mount each of your 8x8 panels vertically and maybe just glue in a couple of nonconducting supports between them for more strength. That way you only have to  run wires down from the columns and the rows are automatically accessible in the base from below.

#### wmfmd

#6
##### Dec 30, 2006, 02:38 pm
That was the plan.. Hardwood base with all the wires concealed inside.

However I'm still lost on how the layers connect to each other.

Each layer has 16 wires, I can hide 8 in the base if I mount the layers vertically going across.. But there's still the problem of the other 8 wires. My idea is to connect them together in such a way that they can draw power from the same source without needing another 8 wires each time a layer is added, by soldering the layers together instead. I should probably start experimenting, I just can't picture how it fits together in my head!

Alex

#### intercranial

#7
##### Dec 30, 2006, 06:28 pm
Hey Alex,

You will still need 16(8 col + 8 row) wires for every plane because the 7219 is sort of using it as a grid where it addresses each pixel individually via a column and a row wire. If you tie any planes together then they would show the same data.

I'm thinking that with your design you bring 1 row wire down at each led.  Use solid tinned wire with no insulation so that it is not so noticable. This leaves your planes totally separate and all your connections in the base. Just like the cube kit that i posted about earlier.
Make sure that the wire is bent out a bit so it doesn't short against the other row wires.

http://www.hypnocube.com/Kit2.php  See the bottom image on that page. it has complete instructions on physically building the led cube.

mike

#### wmfmd

#8
##### Dec 31, 2006, 12:33 am
Mike thanks so much.

I'll post pics of it when it's done, probably by next week.

Alex

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