DESIGN OF A CTD SYSTEM

This was a 6 person group project done as part of my third-year Engineering Design with Management module. The main objective of this project was to design a system that can be deployed in shallow waters (~300m) and measure conductivity (i.e. salinity), temperature, and depth (CTD). Such sensor systems are highly valuable for marine research meaning that most manufacturers target solely researchers and research organisations. However, from our research, it was apparent that the growing aquaculture industry also requires similar systems with the addition of a dissolved oxygen sensor. Therefore we decided to make a modular CTD sensor system that allows for an optional fourth sensor depending on the user's specific needs.

After some preliminary research and having outlined our design objectives, we decided to split the team into two main groups. The first team focused on the electrical aspects of the sensor system and explored the different sensors and microcontrollers available on the market. On the other hand, the second team, which I was part of,  focused primarily on the physical design of the sensor unit Involving a combination of CAD and FEM. However, since the design heavily depended on the specific electrical components we decided to make parts of the sensor housing parametric to enable rapid modifications. Furthermore, this allowed us to continue iterating on the sensor housing despite numerous changes in the sensor choices. Once the electrical aspects of the sensor system had been finalised we proceeded to integrate all the different components into a functional system. 

The final design involved two units wherein the part with all the sensors would be submerged to the required depths and transmit the data to a secondary unit. This second unit would be providing the power to the whole system and would be placed on top of a buoy. This separation allows for easy data collection and recharging of the battery.