click to enlarge - image shows mockup but real hardware built and tested
However I am still asked about this design and how it might be useful for touch sensing applications.
A possible answer is via mobile phones, you are holding the mobile phone and talking to friend but can it replicate the feel of holding hands? The mobile phone is a substitute for holding someone's hand. You could choose to share your heartbeat and also that of remote friend by holding hands. The mechanical actuation technology is much more advanced now, the Microsoft version just used an modified oscillating relay with pulse width modulation (PWM) control to replicate feelings.( Curiously, the prototype was rather good at synthesising the feel of a cat purr , as the software control of the PWM was very fine. ) There are more applications for lie detection, medical apps, games and other fun ideas. It is practical to transmit and replicate skin temperature and conduction.
The only reason the project resurfaced is now the new "smart" actuation technology I have been testing for another job has been built, gone are old solenoids and other magnetic actuators. The new technology provide much more subtle vibration finger stroking effects, is silent and very low power.
Email me if interested firstname.lastname@example.org