The following works for your example, at least:

my $str = 'AR12CR32LC85AR16' ;
my @arr = map { /(.{4})/g } $str ;
print "@arr\n" ;
[download]

Be careful with the distinction between 4-byte and 4-character words -- I believe it depends on what character encoding you use.

Update: OK, that map probably wasn't a good idea... go with the post previous to this instead.

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DamnDirtyApe

Those who know that they are profound strive for clarity. Those who
would like to seem profound to the crowd strive for obscurity.
            --Friedrich Nietzsche