We sense push and pressure with a button that applies linear force to displace the light guide (Figure 11a). As the user
presses the button the receiver changes from a high to a low state (Figure 13a). Elastic deformation causes the light guide
to return to a high state when the user releases the button.The elasticity of the light guide provides clear haptic feedback that can be accentuated with small surface detents on the button shaft.