Bi Colour Led Matrix Problem

Hello I am trying to do the direct drive project from arduino playground, I have a bi colour led matrix. First ignoring the colours, it is random LEDs going at different times, not a message (in program “hello”). And I can get it to display green but when I hook it up for red I get red and green.
What is happening
How do I fix it
Thanks in advance!

Not enough info provided.

What part do you not understand, anyway here: 8x8 screen leds seperated by 1mm http://playground.arduino.cc/Main/DirectDriveLEDMatrix The Hello program (first one) is a scrolling HELLO Hooked up like in the picture When I try the program it is green and red and it is very fast changing I am pretty sure that it still says Hello but its not clear.

Okay, I am not familiar with everything in the playground, that's why I asked. Red/Green matrixes typically have 2 sets of anodes and 1 set of cathode. Or, 1 set of anodes and and 2 sets of cathode. If you are getting 2 colors then there is likely a wiring error. Do you have a datasheet for your matrix? Check that it is correct one. Perhaps you have it installed flipped over, or pin 1 is not where you think it is. As for the program, I am not familiar with that one. It is a very inefficient (in my opinion) way to have the program set up, with 64 bytes of data per character when a mere 8 bytes would do. Worse, since each LED must be driven individually, it is slow to refresh. Adding a single chip to the design, ULN2803, would allow whole columns to be driven at one time, speeding up the refresh rate by a factor of 8 at least. Anyway, since the code has been around a while it probably works. Revisit your wiring.

I found a pattern for how it is hooked up: +Red +Green -Minus continues on but i only connected the red leads? and i get half green half red? :-(

You can not wire up that circuit with a two colour matrix so we need to know how you wired it up.

Did you put resistors in like it said and if so where?

Is your part like this: http://www.futurlec.com/LED/LEDM88RGCA.shtml or like this: http://www.futurlec.com/LED/LEDM88RGCC.shtml

Your pinouts may (are likely) not the same. What you can do is use a resistor, 300 ohm, 330, (value not critical) connected to 5V, and another wire connected to ground, and find which you have. From what you've said: +Red +Green -Minus that sounds like this http://www.futurlec.com/LED/LEDM88RGCC.shtml so you'd want to use pins 23, 20, 17, 14, 2, 5, 8, 11 for the red anodes and 22, 19, 16, 13, 3, 6, 9, 12 for the cathodes. With 23 high and 22 low, that would light up a corner LED, turn your matrix so that is the top left.

Your part likely has a different pinout, so probe it and make your drawing for what you have.

Thanks btw it is common anode and the wiring is 2,3,5,6,8,9,11,12,13,15,16,18,19,21,22,24 for red I think the problem is around 11,12,13 should be 11,12,14,15 Right? But I have wrond pins maybe... I am not using resistors, I dont have enough for all the pins.:/ Thanks!

I am not using resistors,

Then you are actually damaging the pins of your arduino. The arduino pins start getting damage done to them at 40mA. Without resistors the peak current is more like 250mA per pin. What stops it from instantly frying is the fact that they are being switched on and off. This limits thermal damage but does not limit other forms of damage. Please read:- http://www.thebox.myzen.co.uk/Tutorial/LEDs.html

Where should I put the resistors so I can save the most, like not using so many my guess is on the - side of all leds (to use least as possible)?

Can I use it without resistors for testing and when I actaully have it I can include resistors, like how long until the arduino is fryed, is it minor or major problem?

Just tested it and there is still one green and two or three yellow, (red aand green I think) Thanks, help considered.

You need 8 resistors, on either the anodes Or the cathodes. You don't need on both. Keep working the wiring.

Is there any part number on your matrix? Either along an edge, or perhaps on the bottom, maybe on the circuit board itself?

on one side it says YS but thats it

I suggest you probe the part as suggested in #6 then and determine the pin order.

Any suggestions regarding the lone green lights?

i_luv_arduino: Any suggestions regarding the lone green lights?

Unless you can find out exactly what you have we can't tell you exactly what to do. You have to do your part and help us help you.

You're going to have 8 red anode and 8 green anodes, and 8 common cathodes, or, 8 red cathodes & 8 green cathodes, and 8 common anodes. You have to do some experimenting to determine what is where. It is not hard. Take 5V thru a resistor and a ground wire. Touch them to two pins. Say pin 22 is Gnd to start - now touch the resistor to the other pins & see what lights up. If you find a bunch, them you have a common cathode array (the rows in the picture below). Make a note of the low and which pins turn on for the anodes (the columns). The pins that didn't have a light are likely other common cathodes. Move the Gnd to one of those, and what lights up.

If you don't find a bunch to start, switch the Gnd & resistor around, maybe you have a common anode part instead. Be methodical, it is not hard to figure out.

typical common cathode part

typical common anode part

Common +, green is + and red is + and gnd is gnd, so common anode.