i have seen some other posts but i have a question. in an led matrix, if i set one pin as low and another as high, will an led plugged into corresponding pins light up?
If you get the high and the low the correct way around on the LED's anode and cathode leads then yes.
OK I tried to do this but it doesn't seem to work. It seems to be that I am not creating a closed circuit without ground involved. I know I have the LED plugged in correct anode to high, cathode to low).
I guess I thought that low meant ground in some way. I am just trying to figure out a way to light an LED matrix with my arduino.
I guess I thought that low meant ground in some way.
It does. This is exactly how this works: http://www.arduino.cc/playground/Main/DirectDriveLEDMatrix
Are you sure you haven't blown up your LED by overdriving it?
You don't mention a resistor you need one or you will blow something up. Just lighting a LED only takes one pin. Output Pin -> anode of LED. cathode of LED -> resistor. Other end of resistor -> ground.
resistor is there. I was just trying to find out if i were to connect leds in a matrix with one side to pins rated HIGH and the other side to pins rated LOW if I could light the led. I played and discovered that it does not work. Should have tried before the post. Will keep grinding along until I figure it out. Trying to figure a way to light more leds than I have pins, without throwing i other equipment.
Andrew- just saw your post. I will check the link and see where it takes me.
it just occured to me that by hooking an led to two pins I probably bypassed the resistor on my shield blowing the led. I figured I should at least see it light before it blew as I have blown them before. But I am using a 7 segment number led maybe it just blows without any sign. Will try again with a more stable setup. Thanks for the info. Any other tips will be greatly appreciated. I am winging it here.
I played and discovered that it does not work.
If you play correctly you will find it does work.
trying to figure a way to light more leds than I have pins, without throwing i other equipment.
What you need is charlieplexing:- http://en.wikipedia.org/wiki/Charlieplexing