8x8x8 Led Cube inverted, help needed

Other Hardware LEDs and Multiplexing
1

Hi,

I'm trying to do my 8x8x8 led cube as showed on http://www.instructables.com/id/Led-Cube-8x8x8/.

I actually made the led cube and the latch array board. I put the transistors on my breadboard and started to test with my arduino. All the leds lights up and stays on, no effects, nothing.

So, I started debug the circuit and after 2 days I discovered the big, HUGE mistake. I soldered all 512 leds inverted(instead anodes down I soldered cathodes down on columns).

So, is there an easy way to remedy the situation? I really didn't like to solder all my led cube neither loose my latch board. If I have to choose I prefer to make another latch board. As I said the NPN transistors are on my breadboard(easy to change).

Latch board is a 74HC138N(to drive CP pins) and 8 x 74HC574N. Schematic available on http://www.instructables.com/id/Led-Cube-8x8x8/step30/Build-the-controller-layout/

Thanks,

Wagner Sartori Junior

2

:sweat_smile: - yeah, I feel your pain.

Anyhow, here is a simple single diode circuit where I have "accidentally" put the LED in the wrong way round on the left side, and on the right side I've turned the circuit round to match. I switch + and -, I've swapped the NPN for a PNP. This is sort of the way you have to go, I think (have not tested it) This way you ned change anything on your multiplexers or such like.

WrongLED.PNG

3

Thanks for the response.

Do you know a good PNP transistor to switch 1.28A and hFe(min) 160?

Wagner Sartori Junior

4

No, sorry, I dont have an idea.

5

This is what you help me to build. Thank you!