Project: Wireless bone conduction earphones

September - December 2018

Contract work for a startup specializing in screen-free devices: I was asked to prototype a model of wireless, open ear, bone conduction earphones. In three months, I went through 5 iterations of prototypes, to create a working device satisfying comfort, fit and audio quality requirements.

Step 1: Choosing the actuator and contact point

Bone conduction earphones use a vibrating actuator to propagate waves through the skull to the inner ear. The first experiments aimed at choosing an appropriate actuator and finding the best contact point on the skull or the outer ear region.

Step 2: Audio quality

Audio quality depends on the contact of the actuator with the ear bowl to leverage both conduction and reverberation effects. I made a range of 3D printed prototypes testing different spring loaded mechanisms to maintain that contact force, ripping up electronics from a cheap pair of standard Bluetooth earphones and replacing their speaker with our actuator.

Step 4: Improving fit and comfort

3D printed prototypes were not rugged enough, nor were they comfortable. The next iteration was focused on improving fit and comfort, while exploring design alternatives within the realm of mass manufacturing. I made a silicone cast version to increase surface friction on the ear, which could be replaced by an overmolding process during DFM.