A juggling ball tossed above an open hand

MUJU

Movement becomes music: juggling balls with hidden electronics that turn every catch and throw into sound.

UX Design Media Design Product Design 2026

Context

For a university project, I created a happy everyday situation for my chosen 'happy user'. We call the person 'happy user' because the everyday practice we used as a source of inspiration is already a joyful experience for her.

Used programs:

Xcode Claude ChatGPT Adobe Illustrator Adobe Photoshop Adobe Lightroom Arduino

01 Insight & Goal

To take a break from screen time, the happy user uses juggling to create little pockets of calm in their daily life. They also associate the activity with childhood memories. They have been using the balls for decades, and they look the part by now. But they give her a sense of security and serve as everyday companions, both at home and sometimes outdoors. I gathered this information (and also the fact that the fundamental need underlying this activity is security, accompanied by routine, familiarity and comfort) through a semi-structured interview, using the Positive Practice Canvas to record the details.

Positive Practice Canvas documenting the interview about the happy user's juggling practice

02 Idea

Whilst using the 'think aloud' method, I noticed that my happy user often turns on music whilst juggling. To do this, she has to interrupt her practice, search for her phone and connect it to a speaker. This gave me the idea that I wanted to make this whole process not just better, but smoother, and to enhance it with an interesting add-on. So the idea was to connect one of the juggling balls to an app where you can select and link a song specifically for that ball; the music can then be started immediately by moving the ball and stopped by putting the ball down.

Labeled diagram of the ball's electronics: Seeed Studio XIAO-ESP32-S3, MPU-6050 motion sensor, 3.7V LiPo battery and power switch Illustration of the three juggling balls with the MUJU logo on one of them

03 Implementation

So I connected a motion sensor to a Bluetooth-enabled component and, finally, added a rechargeable battery and a switch. I sewed the whole thing into a juggling ball, refilled it and lined it well to ensure the battery and components were protected from impacts. At the same time, I developed an app using Xcode and installed it on my mobile phone. I then connected the app to the ball via BLE. I used various AI systems throughout all these steps.

Early storyboard sketch of the interaction idea: juggling alone, setting the ball down, then picking it up again to music Concept sketch: the soft, filled juggling balls with hidden technology invite throwing, play music or synthesizer tones, and stop with a sound when they touch the ground Close-up of the Seeed Studio XIAO ESP32-S3 microcontroller with soldered wires The assembled electronics: MPU-6050 motion sensor, XIAO ESP32-S3 board, rechargeable LiPo battery and power switch wired together The padded electronics being sewn into the opening of a juggling ball The finished juggling ball with the sewn-in electronics visible through the opening, prototyping circuit in the background
The three finished MUJU juggling balls in red and white on a studio background, one showing the stitched opening for the hidden electronics

04 Outcome & Outlook

The app is set to be further developed. For the original happy user, the experience should stay pleasant, not too overwhelming, and simple; that's what I took away from our discussions. However, the technology now also offers the option to adjust the music based on the speed of the ball, to create music through movement itself, or to use it as a synthesiser.