Isn't your house slanting at different angles? A house is hand-built. There is an acceptable range, but some errors may be observed at the end result. The earthquake-resistant design is emphasized in recent years. So, why don't we check the slant of a floor by ourselves? Are there any tools that easy to check the slant of a floor? We can check problem of our house easily in future. It's 4cm in the length and compact globe. Just put and roll it on the floor and check its bubbles. If the bubbles are over the red zone, it is a signal of safety problem. Bluetooth wireless technology and the measurement sensor to transmit information are built-in the compact globe. The result of a measurement is in real time transmitted to the server in the Internet. They are also designed to ensure that the built-in generator is activated by the movement of floor which accompanies action.