The company Microsoft has developed Skinput, a technology that appropriates the human body for acoustic transmission, allowing the skin to be used as an entry surface. In particular, we resolve the location of the finger taps on the arm and hand by analyzing mechanical vibrations that propagate through the body. This approach provides an always available finger input system, naturally portable and in the body. The main objective of Skinput is to provide an always available mobile input system, ie an input system that does not require a user to carry or pick up a device. A number of alternative approaches have been proposed that operate in this space. Techniques based on computer vision are popular. However, these are computationally expensive and error prone in mobile scenarios (where, for example, optical flow without input is frequent). Voice input is a logical choice for input always available, but it is limited in accuracy in unpredictable acoustic environments and suffers privacy and scalability issues in shared environments. Other approaches have taken the form of portable computing.
This typically involves a physical input device constructed in a manner considered as part of the clothing. For example, glove-based input systems allow users to retain most of their natural hand movements, but they are uncomfortable, uncomfortable, and detrimental to tactile sensation. Post and Orth present a "smart fabric" system that incorporates sensors and drivers abruptly, but given this approach to entry always available, inlay technology is required across all clothing, which would be prohibitively complex and costly. The SixthSense project proposes mobile and always available input / output capability by combining projected information with a colour-based vision tracking system. This approach is feasible, but suffers from severe limitations of occlusion and precision.