This paper presents a minimally-invasive, wireless optical sensorsystem for use with any conventional piston valve acoustic trumpet. Itis designed to be easy to install and remove by any trumpeter. Ourgoal is to offer the extended control afforded by hyperinstrumentswithout the hard to reverse or irreversible invasive modificationsthat are typically used for adding digital sensing capabilities. Weutilize optical sensors to track the continuous position displacementvalues of the three trumpet valves. These values are trasmittedwirelessly and can be used by an external controller. The hardware hasbeen designed to be reconfigurable by having the housing 3D printed sothat the dimensions can be adjusted for any particular trumpetmodel. The result is a low cost, low power, easily replicable sensorsolution that offers any trumpeter the ability to augment their ownexisting trumpet without compromising the instrument's structure orplaying technique. The extended digital control afforded by our systemis interweaved with the natural playing gestures of an acoustictrumpet. We believe that this seemless integration is critical forenabling effective and musical human computer interaction.Keywords: hyperinstrument, trumpet, minimally-invasive, gesture sensing,wireless, I2C