Check for non-empty field

Hey.

I have a field that I want to be be shown if my custom field "jira_project_c" has a value (i.e., is not empty). So I am going to use the "Dependent" attribute/feature of the field. Now I just can´t hammer together the formula :/ 

What I really need is the opposite of    equal($jira_project_c,"")   but there does not seem to be a "NotEqual" function...

Tried:  ifElse(equal(strlen($jira_project_c),0),0,1)  but Formula Builder complains "The formula must be of type boolean"

Help please!

Thanks as always,

KGM