Just started Building my 16x16x16 ledcube.
i just started creating 3 pcb's to stack on each other.
using 4096 blue led's
34 tpic6b595
256 Resistor 100R
16 Resistor 10k
34 Capacitator 0.1uf ( for the tpic6b595)
1x 1000uf 100uf & 10uf (for the supply line)
The picture is updated tnx to PaulRB
please feel free to ask questions or give this noob some advice.
jeroen(netherlands)
What's the largest cube you built so far? 8x8x8 ?
What's the average current that an led in the cube, which is lit, will receive?
If you wanted to light a single led, with 5V supply, not part of a cube, with the same level of brightness, what value series resistor would you use?
I already built a 8x8x8. And a 4x4x4 with ws2812 leds
A single blue led wil use 20mA with 250R resistor.
With 5V supply? No, that's not correct.
And not an answer to my questions. You said feel free to ask questions. I'm curious how you will overcome the problems of building such a large cube.
I think the average current will be about 0.55mA
And to light a single led, not part of a cube, with similar brightness, would need a series resistor of around 3K3.
You are right it’s 90R for a 3.2v led on 5v.
But why would a single led not in a cube use a different resistor.
Supply Voltage in de cube and a single led wil be 5v.
(5v - 3.2)/90= 0.02 is it
Multiplexing
The led will be on with a maximum duty cycle of 1/16th.
And since the maximum output current of the each output of 74HC595 is 35mA, you can't increase it much further. Wouldn't it be better to use 64 pieces of MAX7219? So you will have much less elements and the program for the controlling microcontroller will be much simpler and smaller.
What I suggest is:
It's 70mA. But that must be shared across all 8 outputs.
Each max chip would need to drive a column of 64 LEDs, in other words a column of 2x2x16 LEDs. The wiring would be a nightmare and the cube would be incredibly delicate.
But the 74hc595 controles a mosfet on the anode and cathode.
And only one pin of the sr is high at the time.
In my test the current on the 16th led is 19mA
so each sr has only one pin high each time and controls a mosfet (switch).
the 100R is only to light up one led each time there wil never light up 16 leds at once.
the colum has 16 leds with one resistor and eacht led has a diffrent kathodelayer.
i use these parts cause i have them in stock. and dont need to buy them.
It will be easier to construct your cube so that each of the 16 layers is anodes and the 256 columns are cathodes. Then you can use 32x tpic6b595 to drive the columns/cathodes without needing 256 n-channel MOSFETs. You will need only 16 p-channel MOSFETs. You can drive those MOSFETs with another 2x tpic6c595.
Yes, but the duty cycle will be 1/16, so the average current will be 19/16 = ~1mA. The average current determines the brightness of the LEDs .
1mA is equivalent to a single led with a series resistor of about 1.5K. Try that out to see if you are happy with the brightness.
Kevin Durrah talks about bit angle modulation and muxing (things that trick your eye's persistence).
Try to sim it?!
I hope they put it on plexiglass or polycorbonate.
A pcb on plexiglas?
I am glad you agree.
Very nice.
I make the pcb myself with my cnc cutter.
So on plexiglass is no option for me.
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