UnityBeat — Alexander Xu

An orchestra runs on things you see. The conductor’s baton sets the tempo, a glance tells you when to come in. If you’re blind or deaf, most of that is gone, and you end up following by ear (or not at all). UnityBeat moves those cues to your wrist.

TLDR: a wristband that taps out the beat, driven by where the conductor’s hand is. Four ultra-wideband (UWB) anchors around the podium track the conductor, an ESP32 turns that into beats, and the wristband vibrates them. A phone app sets up rooms, patterns and vibration strength. I was CTO on a team of five and worked across the app, the hardware and the firmware. We were one of 10 national finalists in Samsung’s Solve for Tomorrow, which came with a $50K prize, and demoed it at Georgia Tech’s CREATE-X.

A conductor on a podium inside a frame of four posts while a blindfolded cellist plays — The full test: a blindfolded cellist following the conductor through the wristband in a rehearsal room.

Choosing how to track the conductor

The whole system depends on knowing where the conductor’s hand is, fast. We went with UWB ranging: small radio modules (Reyax RYUW122) that measure distance to each other by timing, accurate to centimetres. One module rides with the conductor, four sit on posts around the podium, and the ESP32 triangulates.

CAD drawing of four anchor posts with measured distances and angles to a central wristband module — Anchor geometry in CAD. With four known positions and four distances, the ESP32 can solve for one point in space.

Before building any of that, we made sure the modules could actually range. Here’s the bench test: two modules on a desk, one moved by hand, the serial monitor printing distances.

Split screen of the Arduino IDE serial monitor printing distances beside UWB modules being moved across a desk — Bench test. Move the module, watch the number change. The caption is burned into the video.

Arduino IDE showing testing_c.ino for a DOIT ESP32 DEVKIT V1 with a serial monitor full of distance and standard deviation readings — The ranging sketch on an ESP32 dev board. Each line is a raw distance, a filtered one and the spread over recent readings.

The anchor frame

The anchors needed fixed, known positions, so we built a PVC frame that stands around the podium.

A student assembling a PVC frame on the floor of a school engineering lab — Building the anchor frame in the engineering lab.

Render of a four-post frame with sensors at the top of each post — The frame as designed, with a UWB sensor on each post.

The wristband

The first wristbands were 3D-printed shells on watch straps.

Two white 3D-printed wristband prototypes on black watch straps, lying on a wooden table — The first two prototypes.

The version we designed next (the render at the top of this page) has a custom PCB with an ESP32-WROOM on it and is rated for up to nine hours of use.

Exploded render of a white sensor enclosure showing the board, the antenna modules and the shell — Exploded view of the sensor enclosure, ESP32 and UWB modules inside.

The app

The app is the control panel. You create or join a “room”, connect the wristbands over Bluetooth, set vibration strength, and pick how the beat should feel: tempo, time signature, subdivision, and which beats get an accent. There’s also a camera scan for sheet music and a score library.

Four phone screens: home with join and create room, dashboard, wristband vibration settings, and haptic pattern controls — Home, dashboard, wristband settings, haptic pattern. The pattern screen is where you'd set a waltz to 3/4 with an accent on the downbeat.

Samsung

We entered Samsung’s Solve for Tomorrow and made the final ten nationally, which meant a $50K prize package and a pitch at The Washington Post’s headquarters in D.C. in April 2026.

Thanks

To Dr. Steven Sweigart and Mr. Young Kim, to Peter Altschul for sitting down with us to talk about playing without seeing the conductor, and to the AFB.