Making a flying star effect with LEDs

[lilimike]

The theory in my head was quite simple, I connected 16 LEDs in a matrix like so:

but physically they are positioned in a single row from LED1 to LED16
I am testing with 16 LEDs but ideally I would do this with 64.

I can turn them on one at a time using this:

portb = %00011110:pause 25
portb = %00101110:pause 25
portb = %01001110:pause 25
portb = %10001110:pause 25
portb = %00011101:pause 25
portb = %00101101:pause 25
portb = %01001101:pause 25
portb = %10001101:pause 25
portb = %00011011:pause 25
portb = %00101011:pause 25
portb = %01001011:pause 25
portb = %10001011:pause 25
portb = %00010111:pause 25
portb = %00100111:pause 25
portb = %01000111:pause 25
portb = %10000111:pause 25

But I actually want to turn them on much like a flying star where LED1 stays on until LED9 goes on.
I was able to get one row lit but I can't figure out how to turn on the LEDs on the second row while keeping the LEDs on in the first row.

Is there a simple trick for this?

Mike

[HenrikOlsson]

Hi Mike,
You need to scan the matrix continously. Ie. do what you did in your example but over and over again at fast rate. The LEDs will blink but if the scan rate is high the human eye won't see it.

EDIT: Just remember not to sink too much current into the B0-B3 pins!

/Henrik.

[lilimike]

Hi Henrik,

It does not show on my drawing but I have a resistor on each led's anode.

For the scanning part I think I see what you mean and I will play with my code. I presume I should make two subroutines for each led (ON / OFF) and have a the main program call the subroutines based on what's on and what's off.
Now the theory in my head is becoming a little more complex...

Mike

[sayzer]

You may use this to create flying star effect.

http://www.picbasic.co.uk/forum/showthread.php?t=10564

[lilimike]

This is going to be handy, I've been pulling my hair out all day trying to figure this out.

Thanks for the link.

Mike

[Charles Linquis]

PLEASE put resistors in series with the LEDs. LEDS ARE NOT INCANDESCENT LAMPS!!