This past week, I’ve essentially finalized the CAD for the drone and have begun testing physical prints of certain components. I finally figured out a design for attaching a tether to the drone, which will allow it to be controlled seamlessly.

Firstly, I finally got rid of the incomplete flat part on the backside of the drone, which had been bothering me for quite a while since I didn’t really know how to proceed, and replaced it with mounting for an ethernet cable tether which will allow me to control the drone better. If you’re wondering, here are a couple reasons why using a tether rather than a wireless connection will probably be more desirable for this project:

Radio waves don’t travel through water as well as air, meaning at certain distances or depths, a wireless connection would have latency whereas a tether would allow for instantaneous communication between driver and drone.

A tether would also prevent the drone from being lost underwater if it were to lose power or malfunction.

A wireless connection would probably require more electronics stuff that I’d have to figure out, which I honestly don’t feel like worrying about.

Because I can’t just plug a tether straight into the Raspberry Pi inside the electronics tube, I knew there would have to be some kind of intermediate connection between the inside and outside of the drone. On Amazon, I found these waterproof female to female ethernet connectors (https://www.amazon.com/ANMBEST-Mounting-Waterproof-Connector-Ethernet/dp/B08HSXGZ5R), which would allow me to plug in a tether to drive the drone without having to take it apart. I created two parts that would screw together to mount this thing onto the drone, first a waterproof enclosure for the end of the connector that would connect back to the electronics tube, and then a cover piece that would fasten everything in place.

Here’s what the enclosure looks like:

Basically, it’s an empty tube of inner diameter 20.6mm, which according to the amazon listing is the perfect press-fit size for the connector. Then, I plan on connecting an ethernet cable on the inner-side, feeding it through the small hole on the side of the enclosure, and then filling the hole with epoxy. This makes the inner-side waterproof while taking up much less space, as the other option would be to use the same waterproof screw-on thing that would go on the other side for the tether, which also takes up a ton of space.

It also has two thru-holes on each side for fastening, which are sandwiched between mounting holes on the main back piece and outer plate, which looks like this:

After finishing that, I’ve basically finished designing everything needed for the drone to function. Tomorrow, I’ll tell you some more about my 3D printing tests, and some lessons I’ve learned as a result.