I have a sliding glass door that leads to my back deck in my room. Now that the weather is nice (and in an effort to save some cash by turning off the AC) I wanted to open the door a little and let some fresh air in. I have a bar laying in the sill of the door while it's closed but it doesn't become short enough for the door to open. What are some other good, safe, secure, I'll-be-able-to-sleep-and-not-worry-about-someone-coming-into-my-room-at-night, ways of securing this door? Thanks!