matt.milan on "in my widget, shortcode $variable parameter not working"

I wrapped a plugin with a widget. i want the widget to tell the plugin what to do by sending the widget $title to the plugin shortcode parameter.

echo do_shortcode('[rotating-posts category_name="blog"]');

works

echo do_shortcode('[rotating-posts category_name="$title"]');

does not.

i tried a few different syntaxes,
_name=$title - nothing happens
_name='$title' - crash

I will post the code in the next comment.