Occupancy indicator
The occupancy indicator is device used to indicate whether a room or bed is currently occupied or not. This page focuses on the device itself, its design and construction. For using rooms, see Room reservation.
Indicators for rooms
- indicator states
-
"free" outside -
"free" inside -
"occupied" outside -
"occupied" inside
This indicator is used to show whether a privatisable room is occupied or not. Pulling down the toggle on the inside of the door hides the "free" state and reveals the "occupied" state on the sign outside. When the toggle is pulled down and the door then closed, the cloth is clamped by the door frame, preserving the "occupied" state. When the door is opened, gravity pulls the block of wood down, automatically returning the sign to the "free" state.
Current design
The current design is the 3rd iteration:
- Old bike gear cable is used. It is freely available anywhere bikes are repaired and very durable. (Brake cable can be used, but it's much stiffer)
- Small wire clamps (bought) are used at end junctions and to limit the toggle distance for the "occupied" state.
- The cloth is a strip of denim. Made by getting an old pair of large jeans, cutting off one leg, opening up one of the seams, sewing it back together as a straight tube, cutting off a slice and punching holes at opposite sides of the slice.
- The cloth is tensioned at each end with a small metal rod with a "C"-shaped bend in the middle. Made by pressing an old bike spoke between an improvised form (i.e. large nut cut in half + fitting metal rod) in a vice. The "C"-shaped bends stick out of the holes punched in the cloth.
- forming tensioner
-
unformed spoke -
tensioner with "C"-shaped bend in middle
Previous designs
The initial design was simply a sign on the outside of the door with clothes peg, where people could move the peg from "free" to "occupied". While easy to implement, it had the disadvantage that people often forgot to move the peg back to "free" when leaving the room. This lead to multiple cases of a room being unused, sometimes for days at a time!
The 2nd iteration moved to the gravity-assisted, door-as-a-clamp design seen in the current design. This design used string instead of cable + cloth. While easier to implement, it had several disadvantages:
- The string would wear out through the constant friction, leading to regular breakages.
- Before fully breaking, the string would often get longer, making it less clear which state the room was in.
- Because of low surface area, the string was hard to clamp, often requiring additional material to be added to the door frame.
- The string would wear out a channel in the door frame, accelerating the previous issue.