Led Cube 8x8x8 problem

[vsnake]

Hi all,

I finished the construction following this guide jacksonliam.blogspot.gr using exactly the same components as shown. Then I uploaded some test code (http://pastebin.com/cPMpj78A) on my arduino and it turned on… sadly only the half (vertically dissected). The other half remained turned-off (not even a glimpse of light).

I tried to change the wire connections somehow to get it work. I got exactly the same result (half lit cube), this time with another dirrection.

I power my arduino via usb from my pc.
I suspect that the power given is less than needed. I tried to give power also with three ac dc converters from Vin port:

first: (output: 3V, 300 mA).
second: (output: 12V, 1A).
third: (output: 12V, 500 mA).

Nothing changed at all. I would appreciate any helping advice on solving my problem.


Thanks in advance.

 

[BobK]

If you have 8x8x8 LEDs and they using the typical 20ma, that would require over 10 Amps to light all of the LEDs. But that does not explain why half the cube would light up, that is most likely a wiring error.

Bob

 

[BobK]

Oh, wait. Of course it is multiplexed. By layer, I presume, so only 1/8 will be on at any time. So the current is more like 1.25 A.

Bob

 

[vsnake]

Thanx Bob for the interest. I'm rebuilding the whole circuit from the beggining. I' ll post results.

Oh, wait. Of course it is multiplexed. By layer, I presume, so only 1/8 will be on at any time. So the current is more like 1.25 A.

Bob

So the bottom line is that we need external power supply? As i know arduino supplies a current of 1A(max).

 

[(*steve*)]

As i know arduino supplies a current of 1A(max).

Closer to 30mA max (per pin) I believe.

Yes, an external power supply is needed with the arduino driving transistors that switch rows and columns.

Depending on the configuration, you may only ever have one LED on at a time (or 1 LED in a layer, or LED in a column/row) but due to multiplexing you will need to drive them quite hard.