Personal area network requires wireless communication system for exchanging information among wearable electronic devices. Intra-body communication that uses a human body as a transmission medium allows wireless communication without using airborne radio waves. Measurements of transmission characteristics of intra-body communication have shown that the optimum carrier frequency was 5MHz. Audio frequency signal was successfully transmitted through a human body using newly developed 10.7MHz FM transmitter and receiver modules, both having the size of 3cm by 3cm. The carrier frequency was selected to utilize commercial RF devices.

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Reducing rigid-body rotational vibration is essential for achieving high-accuracy, high-speed head positioning in hard disk drives. Force transmission in various actuator systems has been discussed, such as a conventional mechanism, a VCM-yoke supporting mechanism, a reaction-force isolating mechanism, and a twin-drive mechanism. The conditions to prevent from rigid-body rotational vibration have been shown. Using a two-degree-of-freedom vibration model, torque transmission to the base due to the reaction force has been discussed. New mechanisms to prevent from rigid-body rotational vibration and to achieve high-accuracy, high-speed head positioning have been proposed.

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In this paper, A miniature abrasion-detecting device for small precision lathe has been developed. A detection principle is to detect the amplitude of the first natural frequency of the cutting tool, which increases with the development of the abrasion. Adopting a small piezoelectric unimorph vibrator as a sensor and an electric power control with an analog switch develops a miniature and low power abrasion-detecting device. The device whose size is 30mm×30mm dose not need a regulator in the electric circuit and works continuously with the coin size battery for more than a week.

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Sizes of what we call general purpose drilling machines might be as big as human being's ones, and they are almost 1 to 2 meters in height. In case of making holes into thin films on the top of small semiconductor's base plates, otherwise in case of picking up small sample from big size specimen to be inspected, these current big machines are not convenient and not efficient in operation any more. Then, we have developed two different types of small drilling machines ; the one is the machine constructed by monolithic parallel spring consisting of hinge mechanisms and its size reaches as small as 50mm in width, 60mm in depth and 100mm in height, and the other is the machine to which the tube scanner is applied and its size does as small as 35mm in width, 55mm in depth and 125mm in height. We report that 400μm holes in diameter has been manufactured by the monolithic parallel spring consisting of hinge mechanism drilling machine and the alphabetic character "T" in the square of 10μm×10m has been done by the tube scanner drilling machine.

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