Vending Machine

6:43 PM vivvzh 1 Comments

Introduction

This is a diagram of a Coca Cola vending machine located near the Emporium in the Lulu Chow Wang Campus Center. All drinks are priced at $1.50 and the machine takes cards, cash, and coins. After testing the machine out, I determined that its usage flow is: 1. swipe your card or insert coins/cash; 2. find your desired drink’s letter and number code; 3. enter letter and number combination; 4. receive drink. The machine’s clearest affordances are its payment options: the card, cash, and coin slots. Notably, the card slot is at eye level, while the cash slot is directly underneath and the coin slot even further down. This prompts the user to use their card whenever possible and establishes the hierarchy of payment options (card>cash>coins). Upon approaching the machine, it was unclear whether I should select my drink first or pay first. You actually have to pay first: once you’ve swiped your card (or otherwise), the LED display changes and prompts you to select a drink by entering the letter/number combination using the 18-button keypad. Though this 18-button keypad is not great in terms of mapping (positions do not correspond to drink positions), it allows for 27 different combinations. When it comes to letting the user know its progress, this vending machine’s primary mode of communication is the aforementioned LED display. Once you’ve selected your drink, of course, you can also see your drink being delivered from the shelves.

Pros and Cons

This machine’s pros are that it’s versatile in terms of payment options, and the labels next to each slot are nicely labeled to guide the user (e.g. the card sticker illustrates which side the card should face). The labels beneath each drink are bold and easy to read. However, many drinks are repeated under different labels, potentially confusing a user who's attempting to differentiate between two or more “options” which are actually the same. In addition, the flat price—$1.50—is unclear at first glance and only displayed in tiny letters next to the coin slot or on the LED screen after you’ve swiped your card. The machine’s accepted cards are displayed twice, which is redundant and confusing since the second sticker includes more accepted cards than the first. Once the drink has been delivered, you have to bend down to retrieve it, which is annoying if you’re carrying heavy things and prohibitive if you have a physical disability.

Suggestions for improvement

1. Prominently display the flat price; 2. move the drink retrieval slot to eye level; 3. separate the letter/number selection buttons from the coin slot and have them displayed much further up; 4. only display accepted cards in one location.