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For the first time, under the actual three‐phase 765 kV power transmission lines, electric field energy is harvested and Zigbee‐based sensor node powered by the harvested energy is operated autonomously. A conductor tube is placed between power lines and the earth surface for electric field energy harvesting. The voltage difference between conductor tube and the earth surface is rectified and the harvested electric energy is stored in a storage capacitor. A self‐sustaining power management circuit adopting low‐power comparator with hysteresis is devised to monitor the stored energy and to operate the sensor node autonomously according to the stored energy. Experimental results under the actual three‐phase 765 kV power lines show that the data transfer period is almost inversely proportional to the square of the height of the sensor module from the earth surface. The temperature data is transmitted in every 25 s when the conductor tube is located at 4 m from the earth surface. Since the presented non‐contact energy harvesting apparatus is very simple, robust and low‐cost, it is believed that the presented technology can be widely applied to power transmission, distribution and smart grid system.

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Key Words : Touch pad, capacitive touch, inkjet printing technology, paper-electronics, touch paper ABSTRACTIn this paper, an inkjet-printed capacitive touch pad is proposed. This touch pad detects contacts of human finger by detecting changes in effective capacitance due to electrical impedance of human finger. A flexible, low-cost and disposable paper is used as a substrate. Inkjet printing technology makes the fabrication fast, simple and environmentally friendly. Measured capacitances of the touched and untouched states are in the range of 163 to 182pF and 218 to 272pF, respectively. The differences in the measured capacitance of each state are sufficiently large to recognize that a finger has made contact with touch pad.