Today, I decided to hone in on the “how” of the components I brainstormed previously. I learned what some of the electronics do in general, and also found some potential candidates for certain parts.

Upon researching, I learned that the Pixhawk flight controller, or more specifically the Pixhawk 2.4.8 I would be using, would essentially be in charge of handling all the low-level control of the drone, meaning reading all the sensors, stabilizing the drone, and sending signals to the ESCs controlling the thrusters. The Pi would be in charge of more heavy processes, like sending high-level commands to the Pixhawk, communicating with the computer, and processing camera footage.

In terms of thrusters, I wanted my drone to be very powerful, so I looked into potential options for motors. After researching, I came up with a couple key findings (that are hopefully correct): 

• Brushless motors should work underwater, as long as all connections are well protected from the water. 

• Brushless drone motors appear to have these KV ratings, which stands for the “motor velocity constant”. It indicates the RPM for every 1 volt applied, meaning a 1000KV motor at 22.2V would run at 22,200 RPM with no load attached to the motor. However, a higher KV also correlates with less torque, meaning in an underwater environment, a lower KV value would probably be more desired.

• The more powerful motors I found were rated 6S, meaning it’s meant to be powered by a 6S, or 6 cell LiPo battery. This comes out to a voltage of about 22.2V.

This would also mean that I would not be able to connect the Pixhawk or Pi straight to the battery, as they are only rated for 5V. After doing some more research online, I found that people typically use a power module to regulate the voltage for the Pixhawk, while I could use a buck regulator for the Pi.

I still need to figure quite a few things, such as how I'm going to eventually connect a controller to the whole thing and how I'm going to program the motors to actually function, but I think that’s enough with the electronics for a little bit. Tomorrow I’ll move on to the design of the drone in CAD.

Oftentimes, I find that although slow, taking baby steps and switching between different tasks is the best way to remain interested and motivated on a project, which is exactly what I'm doing here. See you in the next blog!