I've wanted an electric cello since I was old enough to realize they existed. My parents, both professional classical musicians, started me on the cello when I was three years old. But I gravitated towards an electric guitar as a rebellious teenager, and since then I've anxiously waited to combine the soothing tones of the cello with the warm hum of a vintage tube amp. When I took Neil Gershenfeld's whirlwind class - How To Make (almost) Anything - I knew I had to design and build a cello to call my own.
Most electric cellos are either too expensive or don't have the same "feel" as a traditional instrument. electrello is a low-cost instrument that retains the feel of a traditional cello while allowing the performer to move more freely, due to the motion provided by the four-bar linkages which the player grips with their legs. The bow is outfitted with a wireless accelerometer and vibration motor, packed into a compact 3D-printed enclosure that can fit on any cello bow. The accelerometer records the movements of the bow and can store this data for analysis or use it in realtime. For example, an audio effect - like distortion - could be applied to the sound based on bow speed, intensifying the faster passages of a piece. The vibration motor is primarily an idea for remote lessons, where a teacher can provide haptic feedback to a student in an unobtrusive way.
The body of the instrument contains an android phone, which can wirelessly communicate with the bow and display relevant information based on the instrument's sound. Also, the integrated microphone can stream the sound over the internet, for a web-based performance or a remote teaching session. A $1.50 piezo and simple instrumentation amplifier capture the vibrations from the bridge and convert them into an audio signal, and I have plans to add a magnetic coil pickup to allow for a more grungy and distorted tone. Originally, I wanted the phone to act as an effects box and transcription device, but at the time cellphones couldn't handle simultaneously doing analog-to-digital and digital-to-analog conversion.
Rapid prototyping, musical instrument design, woodworking, electronics design, analog filters / amplifiers, IMUs, Android
The project is well documented on my final project website, with links to download all design files and code freely.