This device measures the shell motions of bivalve mollusks equipped with a Hall sensor in the sea, and promptly detects environmental abnormalities such as red tide and anoxia by detecting changes in their opening and closing motions, and notifies the user via wireless alarm. The system can also be used for basic research on shellfish ecology. Up to 8 channels of Hall sensors can be installed, and the device is waterproof. 

A Hall sensor is attached to one shell of a bivalve shell and a permanent magnet to the other shell using adhesive. The change in the magnetic field intensity corresponding to the distance between the two shells caused by the opening and closing motion of the shells is converted into an electrical signal and measured.  

• Up to 8 Hall sensors can be connected for shell body measurement 
• Up to 4 temperature sensors can be connected for sea water temperature measurement 
• Sensors that do not adversely affect shellfish 
• Wireless unit (optional) for remote control and transmission of measurement data 
• Solar unit (optional) enables stand-alone operation of the system on a raft 
• Waterproof and weatherproof for seawater