Hardware and Software Components of an Oysters' Gape Measurement System

In this work, the hardware and software used in developing a bivalve gape measurement system is explored. This system employs the Hall-effect phenomenon to accurately measure and report the gape of a bivalve. The system uses a Hall Effect sensor (Symmetry Electronics’ H2425) and a small magnet in which both are glued to the exterior of the shells of a bivalve. Consequently, the Hall Effect sensor reports the distance of the magnet, hence the gape opening, to a microcontroller that records and transmits the data to a ground station. This system has been designed to operate in the field as well as in a laboratory environment. In a laboratory setting, this system uses Wi-Fi or Bluetooth to transmit its data. In the field however, due to the lack of availability of power, two setups have been established. The first setup does not transmit data, instead, it saves the data in an SD card within the system’s enclosure. This setup is fully submersible. The battery, microcontroller and SD card reader are all submerged alongside the bivalve. This experiment shows that the system can work for as long as 29 days with a single battery charge. Therefore, each month the battery of this system will have to be replaced if data collection is to continue. The second field system is one that wields cellular network to communicate its data. This is a viable solution since most reefs exist close enough to the shore where cellular signal is available. Additionally, the system includes a solar collector panel for charging the battery during the day and constantly keeping the system transmitting at night. The laboratory system as well as the underwater field system are both fully operational and have been producing gape data for several months. The cellular system is currently being tested and data from all systems will be made available under the MBRACE project data repository.