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Author Topic: can 3 x 3 matrix horizontal anode instead of cathode horizontal?  (Read 526 times)
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san Antonio
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i soldered leds are anode on the horizontal layers. Is there possible using PNP transistor connect the wires? the problem is the Arduino output is always positive.
the pin 13 and 12 are output wire on anode horizontal layers and the ground goes to the ground with the resistors. i m sort of stuck with them i have to remove all the matrix that i already soldered them ... i was trying to do instruction 3 x 3 matrix .
take a look at the picture you will get the idea...

p.s. the green wire from 13 pin connected to first layer, the orange wire from 12 pin connected on second layer. there is no third layer.

please help me what is your suggest? thanks cheer
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san Antonio
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heres picture


* maxtrix.jpg (27.91 KB, 276x207 - viewed 34 times.)
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So, supply a HIGH to the layer to enable it and then turn the LEDs on with a LOW instead?

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san Antonio
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no, not that.

the problem is that i did not following the instruction popular 3 x 3 matrix most these are horiztal negative  each layers. and vertical positive each . i did is opposite way.

should i use PNP transistor output from on Arduino pins, or after leds light on using NPN. i am little confuse that part because i am figure out how can set up each led light turn on with the code.



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I guess I'm an idiot because I can't understand why this cannot be fixed by modifying the sketch.
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san Antonio
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i could not OUTPUT leds from Arduino two pins merge into positive layers. the leds are dim not same as bright before when using only one pin.  i thought it will be helpful using PNP and NPN. but it was not working as well. I guess i have to do rework matrix in correct way.
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Are you referring to the following article?

http://playground.arduino.cc/Main/LEDCube3x3

If not, provide a link to what you were attempting to follow and/or what you have done (schematically, not verbally.)
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san Antonio
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as said " The rows (LED anodes, AN1-3) are driven by BD140 PNP transistors switching +5V on HIGH, the colums (LED cathodes, CA1-9) are driven by BC548 NPN transistors, switchen GND on LOW."

so, for Arduino pin to base using PNP transistors switch. what about using the collector and emitter. meaning the emitter go to rows led anodes? what about collector? is it go to the ground?

it does not explain clearly. or not exist schematic...
« Last Edit: May 19, 2013, 08:31:47 pm by ironheartbj18 » Logged

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Without documentation, how do you know what to build?
One way or the other, conceptually, one level gets enabled and then the LEDs go on, per pattern, one at a time or all at once - can more than one LED be on at any point?
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san Antonio
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i tried to be create then later i did not realized i was huge mistake i was not pay attention the anode and cathode on these leds. the easiest way for me is doing re-work. after that if i learn something new in my mind then i can make the row anodes later on. it was really good article better than nothing for now... i am only learning the beginner electric basic how the transistors works and the codes. i am grealty appreciated for you gave me the link. thanks!
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