mora Music ball, 2015
Mora is an interactive musical instrument in the form of a soft and squishy ball that allows musicians and non to create and record a musical composition using squeezing, tilting, shaking and other playful gestures. Pressure sensors are hidden underneath the exterior fabric and the hardware is located inside. Each instrument (ball) is a node on the network and multiple nodes can publish data to the same software program. The ball is completely wireless and contains a rechargeable battery.
Conductive fabric pressure sensors are hidden underneath the exterior skin of the ball. Each sensor is mapped to an audio loop and this allowed the user to use a squeezing motion to create a musical composition. I prototyped several versions of the conductive fabric sensors using piezoresistive, conductive and semi-conductive materials to get the most responsiveness. The basis of the design was inspired by the work of Berkeley's CNMAT and Hannah's blog at www.kobakant.at. An accelerometer and mechanical buttons are also hidden inside the ball to allow the player more gestures for musical expression.
Sensor data is sent wirelessly over an Xbee network via OSC (Open Sound Control) to a host computer running Max MSP. Each sensor is mapped to a sound loop and the pressure determines the amplitude. A calibration feature was added due to the unpredictable nature of conductive fabric and the heat that was generated from use affected the resistance. I used the sense stage platform to set up the network and allow the data to be transferred wirelessly using OSC messages.