Abstract
Recently, the demand of exploration of deep sea increases. The realization of a simple, a portable and a low-cost deep sea exploration system is also required. The purpose of the project ``Edokko No.1'' is to realize such a simple, a portable and a low-cost deep sea exploration video system. The project members are the CEO of the small companies in Tokyo downtown districts, universities, a research institute, a bank and volunteers of an electric company. The free-fall deep sea exploration video system, we call ``Edokko No.1'' recorded 3 D video of deep sea creatures at 7800\,m of the depth, successfully. The authors, who are the member of the Edokko No.1 project, installed temperature and atmospheric pressure sensors in glass spheres. In this paper, it is investigated that the sensors in the glass sphere is applicable in order to measure the temperature profile of the deep sea and is to detect the moment of the arrival at the bottom or of the departure from the bottom. As a result, it is confirmed that the volume deviation of the glass sphere calculated by the sensor outputs indicates the arrival at the bottom or the departure from the bottom of the free-fall system.
