major household device manufacturerDevelopment division

Solving Power Supply Issues for Smart Home SensorsThe challenge of finding the right power source for “smart home” IoT sensors


Due to recent advances in artificial intelligence (AI) and the Internet of Things (IoT), it is expected that “smart homes”, which include features such as environmental and vital sensing, security systems, and smart meters, will soon play a greater role in our lives. As the client prepared to commercially release a smart home system, the client’s development team investigated options to mount various sensors throughout the home required for the system.

*The Fuji Chimera Research Institute forecasts the market for smart home devices in Japan will grow to 4.24 trillion yen by 2025.


Effective Power Supply for Sensor Installation

The client initially planned to supply power to the various sensors in the smart home using cables, but cabling along walls is unsightly, and concealing of cables inside walls requires major renovations. The client therefore turned to wireless options. However, running the sensors off conventional non-rechargeable (primary) batteries would require the embedding of the sensors and battery units in various locations around the home (in the ceiling, under the floor, and inside appliances), and will create not only battery replacement headaches, but also disposal issues. After considering all the available options, the team eventually arrived at the idea of using energy harvesting and wireless power transfer (WPT) technologies.

Revolutionary Approach Hits a Snag

Energy harvesting, which is the generation of electricity from ambient light, vibration, and temperature differences, and wireless power transfer, which is the use of electromagnetic radiation to transfer electrical energy, are both revolutionary technologies that facilitate the wireless supply of power. In the course of investigating how these technologies could be used to power their sensors, however, the team became aware of issues inherent in these methods of generation and power supply. Since these technologies can only transmit or generate minuscule powercurrents of a few microwatts, they were unsuitable for supplying the required large power needed to obtain and transmit data. The challenge of powering the sensors was so difficult that the development team was at its wits end.

Main Issues

  • The client wanted to build sensors that could be installed in a smart home, but had difficulty arranging the supply of power.

  • The client was concerned that wireless power solutions based on conventional non-rechargeable (primary) battery would create headaches in terms of battery disposal and replacement.

  • While the client wanted to utilize energy harvesting and/or wireless power transfer, the use of these technologies to power the sensors presented challenges because of power limitations.