Tangible Interaction
Winter 2009
School of Design, Hong Kong Polytechnic University
Team: James Geng, Michelle Li
Role: Task scenario analysis, interaction/UI design, physical prototyping, user testing & evaluation
In a Tangible Interaction workshop we examined existing examples of physical interaction to explore alternate solutions to improve the interaction. My partner and I considered the example of the vending machine, in which the physical action sequence of inserting coins, pressing a button to select a drink and bending down to collect the drink completes the interaction process. In Hong Kong, rather than inserting coins however, one may simply swipe the Octopus to deduct the stored-value on the card rather than using coins. The common swooping action of inserting coins/swiping card and collecting the drink is quite simple and universal among vending machines, but there are problem interaction points one may encounter with this existing model. We focused our analysis on the drink machines we found on the HK PolyU campus and carried out a task analysis of buying a drink.
After walking through the scenario we documented the problems we encountered during the phases of transaction, information display and selection, accessibility. Design requirements we considered for a new concept included: natural and intuitive gestures and process, contextualized interaction based on learning and social awareness, easy-to-use interface to reduce errors, encourage exploration and and browsing, create an enjoyable, delightful, and sociable user experience. We then decided on incorporating a contextualized touch screen interface to give users a (virtual) tangible interaction while providing visual information and creating an enjoyable experience.
Design Concept
When not in use, the vending machine’s screen displays featured and most popular drinks to attract and engage passers-by. Sensors can detect when a person is standing in front of the machine, which will then display the drink menu. The menu displays large icons detailing the images of available drinks and associated prices. Users can explore the drink offers simply by touching the drink of interest to view its details (nutritional value, volume, etc.) Users make their drink selection then choose their method of payment. A bucket container for coins allows just one gesture of dropping coins instead of inserting coins individually into a slot. The drink slides out at arm level users can easily grab their drink with little effort.
Prototyping & User Testing
To evaluate our new vending machine re-design, we prototyped a life-sized physical model on which to conduct our user testing. We tested the prototype with 3 users and came up with some initial results to help us make improvements on the next design iteration. Fast prototyping of a physical model allowed us to quickly test and validate our ideas while highlighting problems to solve in the next iteration. In the book The Art of Innovation, one IDEO designer talks about “build[ing] to learn.” And indeed, our prototype helped us shape an improved vending machine concept that was understood by everyone and created an enjoyable user interaction and experience.
