After the ticket-machine at the zoo and the locked-in 24h machine, I now have a new addition for the unusable machines collection :) This time it’s a vending-machine for something very essential: coffee!
Aside from the number-based interface (which will maybe come another time), there is something else very wrong with the design: where do you put your money?
You’ve got 10 seconds to think about this…
…
No, you’re wrong: it’s not the grey thing that looks like the money-slot! :D You actually put your money in the small, nearly-invisible black slit on the right of the number-pad.
The grey-hole is for the “TU/e Coffee Card”. I don’t know anybody who has this card, or anybody who knows somebody who has this card. Anyways even if you had one, you can’t use it since the grey slots are usually filled with coins :)
On other, similar, machines they’ve added some stickers. But of course nobody reads the stickers, and so people keep losing their money by throwing it in the wrong slot.
Solution 🔗
A simple user test would have shown that this design is misleading. But in general, it would be wise to always keep affordance in mind: if a user can put money in a card slot, he will. Not because he’s stupid or malicious, but because putting money in a machine is not the most important thing in his life at that moment. So we should change the “mouth” of the card-slot so that it doesn’t afford to put money in anymore. And besides that the money-slot should be moved to a more convenient location and should be made much more visible. And then of course, we test it again :)