led sign scan problem in moving

[nooshin63]

Hi
I have an led sign with 1/8 scan.
the size of each module is 12*24 and use 74595 shift register and atmega32 as cpu.
but in moving text always there is shadow .for example if we turn on 2 column and move it we will se 3 column are moving.
why we see this problem?
this is from software and method of scan or kind of led and responsibility time of them or ics?
please help me

 

[betwixt]

Usually this is caused by insufficient 'off' time between rows or columns. Assuming it is wired correctly and there are no software or hardware bugs, you need to introduce (or increase) the time between columns the LEDs are all turned off.

Brian.

 

[KlausST]

Yes. I agree this is a software problem... or at least it can be cancelled out by software.
The reaction time of LEDs is very fast. This usually causes no problem.

But your eyes or better say your brain may cause some effects...

Klaus