Final Design Solution

Problem Definition

Plankton are microscopic creatures, which average anywhere from 20 micrometers to over 200 centimeters. As a result, to view these creatures, specific equipment is required, especially if implemented underwater. Underwater mechanisms for in-situ viewing of plankton are commonly used at the Scripps Institution of Oceanography, but are limited to research purposes due to the sheer cost of thousands, sometimes millions, of dollars, and the diverse amounts of engineering for assembly. More affordable options exist, such as the Planktoscope, and can be assembled by anyone, should they purchase the assembly kit from the creator. However, the aforementioned kit does not image directly from the source and requires samples to be placed in the device to take photos. As a result, the objective of this senior design project is to address this gap in plankton imaging and viewing devices. 

Design Solution

The design solution is a plankton imaging device with a waterproof housing and a thruster that is able to propel it downwards through the water column. Plankton will flow through the housing, be imaged by a camera system inside the housing, and exit through the other end of the housing device, encouraged by the thruster. All of the live imaging will be done by an ethernet cable attached to the internal electronics, which will transmit all the data to a laptop or computer. On the viewing device, should the user want to record it, they can use screen recording software to keep the data for research purposes. The entire device, its assembled version, and its 3D model are shown below.

The full design solution includes a housing that is depth rated up to 50 meters, mounted on either end of it with four fins attached to each mount, a thruster, and an electronics and optics subsystem to image plankton and power the device. Within the housing, the electronics and optics subsystems are contained. Additionally, there is a square flow channel tube, through which the plankton may be viewed by the camera system and captured in imaging. The device can be remotely controlled by a Raspberry Pi, which then dictates the desired depth of the device. The depth is measured through the implementation of a pressure sensor on the exterior of the device. Since the device is meant to move vertically through the water, undisturbed by internal waves or its self-imposed thruster, there are measures to maintain its balance, such as the eight total fins and the counter torque mount. 

Testing

During the device’s testing, all of the parts fulfilled their desired objectives. The components to fully assemble the housing (e.g. the outer housing, the flow channel tube) passed their rigorous waterproof tests, with no detected leakage. The electronics and optics subsystems are cooperating together and are able to image objects and transmit the images through an ethernet cable to a computer. With the full, complete assembly, the device is successful in achieving its objective.