State Estimation Method Using Radio Wave Intensity of BLE Beacon Installed Inside Object

With the spread of the Internet of things, a variety of sensors have been attached to home appliances, and it has become possible to obtain life-logs based on the information obtained from these sensors. Life-logs are easy to collect for home appliances that have sensors, but are difficult to collect for home appliances, doors, chairs, and other furniture without special sensors. Previously, acceleration sensors and Wi-Fi radio waves have been used to estimate the state of such home appliances or furniture. However, the estimation accuracy greatly depends on the presence or absence of movement and the size of the estimation object. Therefore, we propose a method to place Bluetooth low energy beacons directly into objects such as home appliances or furniture. This method allows for state estimation based on the radio wave intensity of the beacon, which changes depending on the state of the object. The method was applied to state estimation of the opening or closing of a refrigerator, the opening or closing of a safe, and the occupancy of a chair, and the estimation accuracy was confirmed. Our results showed that the method could estimate the opening or closing of the refrigerator with 99.2% accuracy, the opening or closing of the safe with 93.8% accuracy, and the occupancy of the chair with 98.9% accuracy.