The following movies were taken with a high-refresh rate (60Hz) black-and-white progessive scan camera from Pulnix (model TM-6703) with the help of a Navitar close-focusing macro video lens (model Zoom 7000 TV).
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| alternate_all.mpg (1.8MB) | Initally, half of the piezoelectric actuators are set to the maximum left displacement while the other half are set to the maximum right displacement in a checkboard pattern. The actuators then switch maximum positions from a frame configuration to its inverse. This pattern was used to estimate the maximum actuator displacement by carrying a binarized difference between two inverse configurations. By counting the number of difference pixels and relating this value to a known dimension (such as the actuator's thickness), it was possible to approximate the maximum free deflection to around ±25 µm. |
| travelling_sine_wave.mpg (2.1MB) | This is simply a sine wave that travels horizontally across the ten piezoelectric combs. The pattern is unidimensional. All the tooth-like actuators of a same piezoelectric comb are set to the same time-varying control voltage at all time. In this case, the combs are not subject to any internal cancelling forces such as adjacent tooth-like actuators from a same comb pushing in different directions. Therefore, the overall comb deflection is maximized. |
| two_teeth.mpg (817KB) | Two adjacent tooth-like actuators of neighboring combs move in opposite directions. When the device is loaded with the user's finger, such a pattern compresses and then stretches a small patch of fingertip skin. Note that some cross-talk occurs between the actuators of a same piezoelectric comb. The effect is due to both, mechanical interference (i.e. a moving tooth-like actuator drags along its neighbors) and leakage currents inside the piezoelectric comb. |
| random.mpg (1.9MB) | Each tooth-like actuator follows a pattern of random deflections (256 possible control values). Deflection states vary between the actuator being completely at rest to the actuator being deflected to its maximum position in one direction or the other. As expected, this random pattern does not convey any interesting percept to the fingertip. |
| vertical_pulse.mpg (1.8MB) | Two progessigve sine waves in phase opposition travel vertically across two adjacent piezoelectric combs. This pattern has the effect of successively stretching and compressing an enclosed patch of skin. Most people report feeling a small raised feature sliding under the skin. More interestingly, when the pattern is repeated across the four remaining comb pairs (not shown here), the resulting percept is often described as being a moving edge that scans the finger in the vertical direction. If the sine wave pairs travel at different speeds, interesting percepts can be experienced, such as a rotating edge (not shown here). The motion direction of the travelling edge (up or down) is easily discerned. |
| vertical_wave.mpg (1.7MB) | The tooth-like actuators on the second-to-last piezoelectric comb follow a wave-like pattern that has the effect of a moving compression/stretch boundary on the fingertip skin. |