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Author Topic: 3x3x3 & 4x4x4 led cube schematic help  (Read 4879 times)
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Im sure most of you are tired of seeing these. But Im going to do a 3x3x3 and 4x4x4 before tackling the massive task of the 8x8x8.


I want to make sure Im doing it right, And I drew up some very basic schematics as for what I need to do. Im hoping these are at least somewhere in the ballpark.

3x3x3





4x4x4






So yeah, thats what I have so far, as for led's heres the specs:
Life Rating : 100,000 Hours
Emitted Colour : Blue
Size (mm) : 5mm
Lens Colour : Water clear
Peak Wave Length (nm) : 460 ~ 470
Forward Voltage (V) :  3.0 ~ 3.4
Reverse Current (uA) : <= 30
Luminous Intensity Typ Iv (mcd) : 6000(Typical) ~ 8000(Max)
Viewing Angle : 20~25 Degree
Max Power Dissipation(PM): 80mW
Max Peak Forward Current(IFP): 75mA
Lead Soldering Temperature : 240 Degree (<5Sec)
Operating Temperature Range : -25 ~ +85 Degree
Preservative Temperature Range : -30 ~ +100 Degree


Not sure what resistors I need though.
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The 3x3 is missing resistors for the transistor switches.  There should be a resistor between the data pin and the Base of each transistor.
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Resistors:
(Vsource - Vled - Vswitching transistor)/LED current  = resistor

(5V - 3.0V - 0.7V)/.02 = 65 ohm, 68 is a standard value
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Here's the schematic of what you are intending I believe. Add a DPDT switch to disconnect D0/D1 for reliable code downloading.

For 8x8, need 64 LED across, and twice as many rows.
I think a Mega has enough IO for that. Or use SPI.transfer's into 8 shift registers for the 64 across, and 4 more IO for the transistors - which will then need to sink
1.5A each. (just 11 pins!)


* 4x4LEDmatrix_transistors.jpg (93.83 KB, 960x720 - viewed 367 times.)
« Last Edit: November 25, 2011, 12:01:05 pm by CrossRoads » Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

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