Row Column Scanning not working

Using Arduino LEDs and Multiplexing
1

hello, i tried to follow this tutorial: http://arduino.cc/en/Tutorial/RowColumnScanning

but the whole matrix is always lit and only one row and one column does not light.

for the x and y coordinate i didnt use the analog input but i change them programmatically with a delay(500);

i am pretty sure i did the wiring correct. what else could i have done wrong?

here is a photo:

2

"LEDs arranged in rows of common anodes and columns of common cathodes, or the reverse."

Try switching rows and columns. I think the symptom you have is what you get when the LED's are backward from what you expect.

3

thanks! do you mean changing the order in the code or the pins on the arduino? or is that the same?

4

emzic:
thanks! do you mean changing the order in the code or the pins on the arduino? or is that the same?

You can swap the rows and columns three ways:

  1. At the display, disconnect the row wires, move the column wires to the row contacts, and connect the row wires wire to the column contacts.

  2. At the Arduino, disconnect the row wires, move the column wires to the row pins, and connect the row wires wire to the column pins.

  3. In the sketch, move the list of row pins to the columns array and the list of column pins to the rows array.

Pick one or pick all three, just don't pick two since that results in no change.

5

thank you! tried all of the three options with the same result:

no led is lit as you can see here: http://deviantsart.com/upload/1qhh619.jpg

but the small led with an L directly on the arduino is lit. i think this indicates that the program crashed, right?