The Interactive Ultrasonic Theremin is a fun STEM project that combines ultrasonic distance sensing, programmable sound generation, embedded programming and 3D printing into one engaging interactive build. Instead of pressing traditional keys or buttons, the instrument responds naturally to hand movement, allowing users to play musical notes by simply changing the distance between their hand and the ultrasonic sensor. Using a Kypruino board, an HC-SR04 ultrasonic sensor and a potentiometer, the theremin detects hand position to generate musical notes through the Kypruino's built in buzzer. The potentiometer adjusts the depth of a vibrato effect, creating a more expressive playing experience while demonstrating how sensor data can be converted into real time sound. Designed for makers, students and educators, this project introduces key engineering concepts including ultrasonic distance measurement, analog input reading, musical note mapping, sound generation, signal filtering, embedded programming and 3D printing. The custom 3D printed spherical enclosure transforms the electronics into a compact musical instrument while showcasing how hardware, software and digital fabrication can come together to create an innovative STEM project. Perfect for makers, students, classrooms, workshops and STEM education. Highlights: Gesture Controlled Musical Instrument: Play musical notes by simply moving your hand in front of the ultrasonic sensor. Adjustable Vibrato Effect: Use the potentiometer to control the vibrato depth and create more expressive musical tones. HC-SR04 Ultrasonic Sensor: Learn how ultrasonic distance measurement can be used as a real time input device. Beginner Friendly: Explore sound generation, sensors, embedded programming and 3D printing through a hands on project. STEM Learning Project: Combines coding, sensor integration, music technology and digital fabrication into one engaging build. Specifications: Project Type: Interactive Ultrasonic Theremin & 3D Printing Design. Main Board: Kypruino or Arduino Compatible Board. Distance Sensor: Ultrasonic Sensor HC-SR04. Control Input: 10K Rotary Potentiometer. Sound Output: Buzzer (onboard on Kypruino). Communication Interface: Digital & Analog I/O. Digital Output: Buzzer (D9). Ultrasonic Sensor: TRIG (D4), ECHO (D5), Vcc (5V), GND (GND). Potentiometer: OUT (A0), VCC (5V), GND (GND). Power Supply: USB Type C. Shell Type: 3D Printed Spherical Theremin Enclosure. Features: Gesture controlled sound generation, chromatic note mapping, adjustable vibrato, signal filtering and programmable musical effects. Application: STEM education, coding, electronics, music technology, sensor projects, embedded systems and 3D printing. Theremin Dimensions: ~108×117mm. Kit Weight: ~120g. Complete Kit Includes: 1x Kypruino Compatible Board. 1x Ultrasonic Sensor HC-SR04. 1x 10K Potentiometer Module. 7x Male to Female Dupont Wires. 1x USB Type C Cable. 1x 3D Printed Spherical Theremin. Project Resources: Source Code & 3D Printing Files. Step by Step Project Guide. Ideal For: 🎵 Interactive music and sound projects. 📏 Ultrasonic sensing and gesture controlled applications. 🤖 Electronics and embedded programming. 🔊 Sound feedback projects. 🎓 Arduino & STEM education projects. Note: Spherical Theremin color may vary slightly from the images shown. Requires basic assembly and Arduino IDE programming. USB Type C cable is required for programming and power. The code can be customized to modify the musical scale, playable range, vibrato effect and sound behaviour. Full project instructions, wiring diagram, source code and 3D printing files are available on our Blog.
