Self-Powered Sensors Send Out Signals with No Power Failure Combining Energy Technology with Sensor Networking

Unused energy resources abound. Sunlight shining into buildings, human movement, vibration, and other such sources contain so little energy that they have been largely ignored. Engineers are now studying ways of using these small sources of energy for power generation. The implementation of micropower device and module technology is just around the corner.

Katsumi Fujimoto General Manager, Product Development Dept. 2, New Technology & Products Development Group, Technology & Business Development Unit


Fujimoto joined Murata Manufacturing in 1981 and engaged in developing piezoelectric filter, resonator, and actuator products. In 1989, he started to concentrate on developing piezoelectric vibratory gyroscope technology to the mass-production phase and in the course of time he worked in Kanazawa and Toyama. He was transferred to the Device Business Unit in 2006 before assuming his current office in 2008. Fujimoto is convinced that optimistic and flexible thinking and indomitable perseverance are the keys to successful development. His favorite pastime is woodworking. He changed the room layout and finished the interior of the second floor of his own home—all by himself.

Murata is now strengthening its commitment toward developing environmental and energy technologies.
Electric power can be generated not only at large power plants, but also from energy sources at home and work, and in cities and towns that have been largely ignored in the past.
Representing the ultimate in environmental responsibility, energy harvesting is now being put to practical use.

Microenergy Enables Sensors to Send Out Signals with No Power Failure

This new technology exploits microenergy resources available in our everyday environment to drive a sensor network. Energy sources such as sunlight coming into your home, water temperature differences, pressure generated as you turn a switch on or off, or the vibration of a car body can generate 100 to 500µW (microwatt=10-6 watts) of power, which can be used to activate sensors and send out signals by radio. Energy harvesting technology enables Murata sensors to power themselves with no conventional power supply, cabling, or batteries. Once installed where they are needed in your office or home, they send out data indefinitely with no power failure.

Exploiting Human Activity to Power Human Movement Sensors For Optimized Lighting and Air-Conditioning

The movements people make when they open a door to enter a room, for example, can be exploited to generate the power required to switch on specific lights. The central control system detects which doors are opened and which rooms are being used, monitors human movement, and adjusts air-conditioning to concentrate on occupied space. Once a room is left unoccupied, the system turns off the room's lighting and air-conditioning. Data on such uses are processed using a PC and controlled by cloud computing. This technology is advanced in Europe and has been introduced in many buildings.

In Japan, we have yet to see its full-fledged introduction and have only reached the point where energy control has been visualized. Murata has started trial operation of a self-powered wireless lighting switching system introduced at the head office of Toda Corporation, a construction company. Using wireless technology makes it possible to achieve non-directional lighting control and eliminate cabling, which helps reduce installation costs. With this technology, we now aim to develop new business in the building remodeling market.

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