Where is Everyone? - Keeping Track of Students

I have a terrible memory and can never remember who asked (or how many) to go to the washroom.  I'm also very visual (and have poor distance vision!).  I needed a system to keep track of who has left the classroom at any point during the day. It had to be easy enough for students to use themselves (quickly), and big enough for me to see from anywhere in the classroom. This is a system a colleague and friend of mine used when I was an educational assistant in her room. It is my favourite way to keep track of students.

Each student has a pocket on this poster. Their names are there but I hid them with the green "tape" to respect their privacy in this blog post. I have different coloured cards for Absent, Washroom-Boys, Washroom-Girls, Office, Library, and Other. When students leave the room, they insert the correct card in their pocket, and remove it when they get back. For washroom use, I only have one card for boys and one card for girls. Students don't need to ask permission to use it (as long as I'm not in the middle of a lesson) and that way I'm sure that there is only one gone at a time.  When a student is absent, another student (or myself) puts the Absent card in their pocket. It helps me when I take attendance, but also when the older kids come to deliver the milk before lunch and they don't need to interrupt me to ask who's away. 

A quick glance at the chart and I know where everyone is!

Now... on another note... my OCD self is SUPER annoyed at THIS!  This is going to bug me all year! 

How do you keep track of your students who leave the room?