Report on ATHack (Assistive Technology Hackerthon). A few MIT students and I worked with a Co-Designer who has left with her deafness. Her situation was that some visitor comes to her house and rings the bell, she cannot realize it. 
So, we developed and built a small, comfortable and adorable designed wearable haptics device, called “Tact Bell”, that functions as an intuitive vibrator when someone rings a bell. 
As result, the co-designer was very very happy and we won also award.