Machine On Campus
The device I chose is the card scanner to enter the engineering lab. It is simple: a box with a vertical slit the entire way down and a light. There are no signs. When one tries to push or pull a card or thin paper through the slit, the light either flashes green or red to show the acceptance of the slide and entry into the room. Green is an accepted reading, while red is denied. The user can slide something thin through it and little else. There are no buttons or other levers on the box. Affordances are the slit. It is pretty intuitive that you run a card through it. There is no signage telling you which direction or what kind of card, that is dependent on the community. As the door doesn’t open unless the card is accepted and it is a pretty straightforward machine, the user knows what to do based on the simplicity of the design. The only outward indication that your swipe was successful is the green flash, however. It is very easy to miss. It might also be difficult for people who are color blind or blind as the system is very visual. I would suggest a noise when the lock disengages to let you know it was successful.