# How do you turn on a specific LED in an LED Matrix

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## 4 Replies - 873 Views - Last Post: 19 March 2015 - 11:20 AM

### #1 jwag

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# How do you turn on a specific LED in an LED Matrix

Posted 17 March 2015 - 04:15 PM

Hello, I'm in a software engineering class and we are developing a micro controller to control an LED matrix. We need to specify what LEDs to turn on and off in the matrix. So I have done some research and I have found that LED matrixs work in a way that lets say we have a matrix with 4 rows, and 4 columns, each cell is an LED, if we want to turn on the top left LED, or the LED in column 0 row 0, we set the column value to 1 and the row value to 0, 1 being high and 0 being low. If a cells row and column value are both 0 (low) or both 1 (high), the LED wont turn on.

So the matrix checks the first LEDs values and turns it on or off depending, then it moves one LED to the right, continues this until it hits the end of the row, at which it will move to the next row and start at the first column again.

My question is, lets say I want to turn on the top left LED and the bottom right LED, how do I do this without turning on the top right LED and the bottom left LED.
Example:

--1|-2|-3|-4
A|on|--|--|--
B|--|--|--|--
C|--|--|--|--
D|--|--|--|on

I would set row: A and D =1
and columns: 1 and 4 =1, so the LED would recognize
(A,1) and (D,4) as on, but the issue is it would also recognize
(A,4) and (D,1) as on, but we don't want those on.
How do I resolve this?
I have done a lot of research and I just can't quite grasp the concept, any help is appreciated! Thanks!

PS. I ran into this article that might explain my issue better, I can't follow how they resolved it though:
http://www.appelsiin...led-matrix-work

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## Replies To: How do you turn on a specific LED in an LED Matrix

### #2 modi123_1

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## Re: How do you turn on a specific LED in an LED Matrix

Posted 17 March 2015 - 04:32 PM

What's the hardware setup you are using?

### #3 jwag

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## Re: How do you turn on a specific LED in an LED Matrix

Posted 17 March 2015 - 04:53 PM

Well haha, it's actually virtual. We are using a software called MiniAT. It acts like a microcontroller and we have to program it as if it were one.

### #4 modi123_1

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## Re: How do you turn on a specific LED in an LED Matrix

Posted 18 March 2015 - 08:26 AM

Okay - then that example link sort of spells it out for you. I am not sure what your virtual toolkit looks like or has as options, but that tutorial's logic is sound in the real, and virtual, world.

### #5 jwag

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## Re: How do you turn on a specific LED in an LED Matrix

Posted 19 March 2015 - 11:20 AM

modi123_1, on 18 March 2015 - 08:26 AM, said:

Okay - then that example link sort of spells it out for you. I am not sure what your virtual toolkit looks like or has as options, but that tutorial's logic is sound in the real, and virtual, world.

It does help a lot! Thank you! +1