Embodied Interaction

MINEFIELD

Minefield is a tangible memory game that promotes embodied interaction. The game is a race between two players. Each player has a pathway composed of 7 footsteps and they have to take one step forward at a time, always choosing between two options: left or right tile to step on. One tile is safe and the other has a bomb. When the game begins, the bombs are revealed for 2 seconds and players have to memorize where the bombs are (as many as possible, of course). If a player steps on a bomb, he or she has to go back to the starting point, remembering all the correct paths. The player who crosses the minefield first is the winner.

Creators: Renata Kuba, Hugo Lucena & Sung Hoon.
Tools: Arduino, electrical components, projector, white fabric, foam, and copper papers.

Challenge

Create a Tangible User Interface (TUI) game and integrate a computer seamlessly into the experience. This idea was inspired by the movement of ubiquitous computing that proposes a vision where computers would work backstage in an attempt to make them invisible. In addition, in this TUI challenge, we wanted users to interact with the embedded digital information by using gestures and movements.

Proposal

Design and develop a life-sized physical game that invites two players to compete against each other. The game was designed for children, but adults were also welcomed to play. The idea was to create a game that could be played multiple times, and each time would last approximately 5 minutes (so many people could try the project). This project was part of a two-day exhibition at Tisch in New York City.

Fabrication

To create our life-sized board we used copper papers, foam and white fabric. We brainstormed various ideas to make the circuits open and close. In our first attempt, we used aluminum foil, but the electrical conductivity was too low. Thus, we replaced them for copper papers, which were better conductors and made our installation more reliable. We sandwiched a foam with those copper papers, and we cut a hole in the middle of the foam to allow the copper papers to touch each other when a player steps on them (closing the circuit). Lastly, we sewed the hardware inside a white fabric to hide the wires and materials and to project the graphic images on it. To guarantee that players would step on the right place to close the circuits, we drew footsteps to indicate where players have to step.

We tried different foams to validate which one would have the right amount of flexibility when users step on it.
Each breadboard represents one player’s path.
We drew footsteps on the fabric to indicate where players have to step on.

User experience

Users can play the game multiple times since the bombs are randomly distributed in each round. For every step, players would receive a feedback message such as ‘go back to the starting point’ or ‘go ahead’. We conducted one rapid prototype test and one usability test and we also received many peer feedback to validate the game rules and the output messages.

In general, players could easily understand the game mechanics.  Some participants reported that having visual elements such as color and shapes would help to distinguish the essence of the messages. Based on the feedback, we added a bomb animation right on the tile where player is stepping, followed by a red rectangle displaying the ‘go back’ message. In contrast, for the ‘safe to go’ message, we displayed a green square with the ‘safe’ message, followed by the green arrows indicating that player could make the next move. In addition to the visual responses, players could hear output sounds such as a bomb exploding.

One participant reported that was difficult to know when his turn was to take a step. To solve this problem, we added a message stating ‘wait for the other player’ or “move” so player would know what to do.

We used a projector to place the graphics on the board. Because the ceiling was not high enough, we used an external application to project the image in perspective. However, putting a project in an angle different from 90º meant that players would have shadows on the board. Thus, we checked various angles to put the project in front of the board, without flashing too bright light in the players’ eyes.

We designed the interface using various brushes in Adobe Photoshop.

Interaction scheme

Exhibition

The showcase was part of a two-day exhibition at the ITP Winter Show 2014. Whenever there were users playing the game, some people would gather around to watch and stay ready to play next. We built this project as part of a 14 weeks class and it was an unforgettable challenge for us. As a positive result, our instructor selected our project to be an example for her future classes. It was an amazing process!

THANK YOU SO MUCH TEAM!