MusiSkate is a hardware accessory for skateboards that connects with audio outputs to provide real-time musical feedback to skateboarding motions and tricks. It aims to improve the experience of skateboarding, especially during the learning phase by staying true to aspects of the experience, like "learning by doing" and "play", that are essential and already present in daily skateboarding activities. MusiSkate is simple, non-intrusive and augments the expressiveness of skateboarders.
First things first
MusiSkate was undertaken as a semester long project for the "Introduction to HCI" course at Georgia Tech. The work we did for this project and the results from our research were published in the Proceedings of MobileHCI 2016 conference held in Florence, Italy.
When we began this project we didn't know a lot about the sport of skateboarding or the problem space as none of us were skateboarders ourselves. We were given a prompt to do a project that related to the theme of "HCI on the go". We decided to choose skateboarders as our primary users to conform to the theme and to due to our shared interest in experiential sports as a team. We conducted extensive user research to learn about our users and the sport from which, we found out that the biggest problem with skateboarding lies during the learning phase of the sport.
- Being an experiential sport, learning how to skate on a skateboard is a hurtful task as people fall and get hurt quite a bit when learning to practice new tricks
- Skaters don't practice tricks in groups for fear of failing in front of a crowd, this makes rewards for landing a trick while practicing hard to come by, leading to decreased motivation
- Skaters as people have very raw and romantic feelings about the sport and resent addition of technology that gets in the way and was introduced for the sole purpose of commercialization.
- Skaters like that their sport is perceived to be very "cool". They would therefore not use any kind of new technology that didn't add to the coolness factor of an already "cool" exercise.
Goals and Constraints
Based on the problem space that we were tackling, we decided to build a piece of technology that would be
- Modular and simplistic to use. Skaters could attach and remove it to and from their skateboard anytime they wanted.
- Non-intrusive and would leverage existing practices to seamlessly blend into the skateboarding ecosystem.
- Enhance the experience of skateboarding and also help make the tedious hurtful process of learning how to skate easier.
The final solution
MusiSkate involves two modes of operation. One mode called, "Tricks for Tracks", aims to provide a secondary goal of unlocking the complete music for skaters to achieve. The second mode called "Freestyle" aims to encourage the explorative side of skaters so that they feel encouraged to try new tricks.
- Tricks for Tracks: The users need to perform a set of tricks consecutively in order to unlock hidden tracks of music. At the start of the challenge, the user is presented with a new choreography of skate tricks and a musical master track is played. Let us say it is just the drum beats playing. As the user completes a trick, a new musical track is unlocked (let us say the guitar track) and added on top of the master track - this results in a richer sound.
- Freestyle: The movement of a skateboard is directly mapped to musical tones and frequencies. The twists-and-turns and swaying movements of the skateboard either generate corresponding musical movements or plays suitable sound clips. Thus the skater becomes his/her own conductor. The music acts as a rich feedback for the skater and has the potential of enriching the overall experience by elevating the skating sport to an artistic level.
Process in detail
None of us (my team) was a skateboarder. We didn't have any in-depth knowledge about the sport and as such, we were not really sure what to build for our users. So we began with a clean slate and decided to go out to a couple of skate parks and ask the people skating there about their pain points, problems, a day in their life, what they like etc. In general, our goal was to get an in-depth understanding of our users and the context so that we can decide which is the main problem that needs to be tackled and more importantly, which is the main problem that can be solved through a technology-driven product. We conducted 11 interviews in 2 skate parks and 1 skate shop in the greater Atlanta area.
Analysis of interview data
After conducting all the interviews and gathering all our notes to form the information pool we had to sort the data to identify the problems that were most important. We coded all the data from the interviews on sticky notes and created affinity diagrams which were iterated upon and revised to identify the major themes that emerged from the interviews. This exercise helped us identify that skating is
- Simple: Less about gadgets and trends but more about mastery of skills and robust equipment.
- Hard: Trial-and-error, repetition, and research are all part of learning.
- Social: Involves friends, families and even strangers at parks.
- Personal: Customizing skateboards as a way to assert individuality and preferences.
- Musical: Listening to personal music as a norm.
Top 3 choices for final solution
Feedback session for ideated solutions
Up until now, we were following the evidence. Representative users said these were the problems which were confirmed by observations conducted by us in the context of use. We needed feedback at this point to confirm we were on the right track. We presented our ideas to experts (professors, alumni, and seniors from the HCI program) and asked them to critique our ideas
- The first two ideas were very well received by our reviewers. They specifically liked the second one due to the possibility of social involvement through collaborative jam sessions conducted through skateboarding stunts and even possibilities of turning out good quality produced music that was created through extreme sports.
- The reviewers were skeptical about the third idea due to inherent limitations of cost, resources and time that would be spent in prototyping. Furthermore, it was also pointed out that it is generally not fun for actual outdoor athletes to play their beloved moving sport indoor on a stationary object.
Based on the feedback we received we decided to go ahead with the idea of providing real-time musical feedback to skateboarding movements.
Low fidelity prototypes
High Fidelity Prototypes
Over the next few days, we implemented two physical prototypes of higher fidelity. One, using an android phone to detect skateboard tricks. Second, using an inertial measurement unit sensor and an Arduino to understand its movements. The Android app demonstrates the track unlocking functionality of the system based on successful trick completion (Tricks for Tracks). On the other hand, the IMU sensor based prototype demonstrates the real-time audio feedback on freestyle skateboarding. We went in this direction of implementing two separate prototypes because:.
- There are two main aspects to our design idea: feedback on trick completion, and immediate audio feedback on movement.
- We decided to implement each of these functionalities in a parallel way so that the whole concept can be prototyped in a short period
Heuristic evaluation of the prototypes
We enlisted the help of our classmates to evaluate the designs of our prototypes based on the following heuristics.
- The design must have clear and suitable volume.
- The design must match user’s perception when representing data.
- The design must/can be both noninteractive and user-initiated.
The evaluators then took turns in using the prototypes. We set the context for them through a scene description and they were asked to provide feedback by taking the context into consideration. The major issues uncovered were with the Tricks for tracks prototype
- Use a better song that has all the tracks (guitars, drums, bass) all playing at once so there will always be feedback once a certain track is activated
- Different tracks must be easily distinguishable from each other (e.g., guitar vs. bass layers) to provide clearer feedback
- Reduce feedback delay for unlocking new tracks
We conducted a usability study of our prototypes with three participants that we recruited. The purpose is to determine whether the prototype works with its intended users and to improve our design
- What is the effect of audio feedback on the satisfaction of performing tricks on skateboards?
- What are the differences between our two prototypes in increasing the satisfaction of skating?
The metrics we used to measure the effects and difference were - Enjoyment, Usefulness, Appropriateness, Meeting of expectations and Future use. The participants scored their experiences by rating these metrics on a Likert scale of 1 - 5. The threshold of acceptance to indicate an enhanced experience was 4-5.
We recruited 3 skateboarders we met on the Georgia Tech campus to participate in our test. As undergraduate students, their age ranges all fell under 18-24. Two of them have 1-5 years of skateboarding experience, while one person has 6-10 years. All of them describe themselves as "intermediate" skaters.
We scripted a few tasks for the participants to perform based on the tricks that our systems could detect.
- When the participants first arrived we showed them the proof of concept for MusiSkate.
- We then asked them a questionnaire and recorded their response.
- The next step was to ask the participants to perform the tasks we had scripted.
- Once that was done we asked them to fill the same questionnaire again but based on their experience with the system.
The analysis of the pre and post-task questionnaires helped us evaluate the prototype.
In general, the ratings for Freestyle remained constant for the pre-test and post-test questionnaires, implying that it met the users’ expectations of the system.
One thing to note is it did not meet the threshold of 4 for usefulness, which shows that it was perceived to be more entertaining than useful. This can be due to the fact that the Freestyle interaction does not utilize a rewarding methodology but concentrates more on bringing out the creative side of the skater. This creative aspect will become more prominent when a larger number of tricks and movements can be mapped to widely varying sound-effects and also when the user gets the choice of choosing his/her own music track.
For Tricks for Tracks, the usefulness and future use increased (median = 4) and dropped for appropriateness (median = 4), which can mean the users felt it exceeded their expectations but the music must be more customizable for their own purposes. Overall, the prototypes met our threshold of acceptance of 4-5 on the Likert Scale.
Major issues revealed
Fragile prototypes: The prototype we made for the study broke during one of the studies due to which we had to go to Plan B and use Wizard of Oz. This made us realize that we should have made the prototype more robust.
Transferring control to the users: both our prototypes need to be redesigned such that users have more control over the kinds of audio feedback they want to receive.
- The entire study needed more users to get more consistent and reliable data.
- The participants confirmed that our design choices of using the skateboard to generate sound and control music was perceived as a really “cool” and motivational idea.
Freestyle is good for repetition and improvisation. Tricks for Tracks may be useful once skaters have gained mastery of tricks.
Moreover, while Freestyle was perceived as more fun and creative, Tricks for Tracks was perceived as more rewarding and useful.
During our research we uncovered the following questions which promise to be interesting directions for future work
- Consolidation: Can we combine both prototypes into one device?
- Modularity: How can we easily attach our prototype to any type of skateboard?
- Sociality: How do we leverage the competitive and cooperative aspects of skating?
- Higher rewards: How can the system detect and reward more complex tricks through audio effects or gamification?
- Robustness: How can we improve the aesthetics of our system and prevent it from getting damaged?