SRS1 - Project Idea

1. Introduction

Hi! This will be my first blog for the Experimenting with Waterproof Connectors Design Challenge. My kit is currently in customs here, but to meet the deadline for the first introductory blog, I’ll give a short overview of the project I plan to work on during this Design Challenge. First, of course, let’s begin with the name, the SRS1. This name draws the inspiration from the same thing like the drone platform I made a few years back, called the SRD1, how to the names sound both draw inspiration from the SR71 Blackbird plane of course, the SRS1 stands for Science & Research Submarine 1. In testing all of the connectors, my idea for this challenge is to make a small submarine platform that I can then upgrade overtime to conduct different experiments, whether that is adding a gripper, sensors, cameras and so on. I’ll now take you through some concept ideas I have for this project, which will change for sure as the project itself progresses forward.

2. Idea

I’ll begin this part with a professional render of my idea:

As you can see from my drawing, my idea is for the whole system to consist of 2 separate parts. But why do we need 2 parts, a floating one and a submerged one? The reason for that is that radio waves have a hard time going through water, so we would have a lot of issues if we tried controlling it wirelessly like that. This way, we have a floating part to which we can easily communicate, my choice for this will be LoRa, since it’s really easy to implement plus, the range on it is really good. Another great thing for having a floating part is that we can actually have some idea of where our system is, which wouldn’t be the case if we could communicate with the sub completely remotely. To communicate with the sub itself, there needs to be a data cable that goes between the floating part and the sub. Since everything about this project will be around water, there will be a great need for waterproofing stuff which is why I wanted to do this for this Design Challenge.

Let’s take a closer look now at the 2 sections of this project starting with the floating part.

There are a few key factors that the floating part needs to accomplish, those are to provide a wireless link to the operator, to have power on board, to communicate with the sub and to control how much cable the sub is currently using. Some key components that will need to be on the floating part (that I need to name too):

• Floatation devices - cold be anything from pieces of plastic pipes to bottles
• LoRa radio - this includes the Arduino MKR WAN 1300 plus an antenna for it to increase the range
• Data cable & cable feeder - there needs to be some kind of mechanism for controlling the amount of cable that the sub can use, too little and the sub won’t be able to go where we command it, too much, it can get tangled in something
• Sensors - We can have additional environmental sensors onboard
• Battery and power electronics - depending on the weight of the sub, the sub may have an additional battery but we for sure need power above water too, the floating platform should also be able to have some kind of propulsion so it can return to land if the sub breaks down.

Now on to the sub itself.

This is not even close to how the sub will look like, but one idea I like is using a pipe construction for it, since pipes and the fittings for them are designed to hold water in, so they should be able to keep water out as well! Would this configuration of motors work? Probably not, I’ll probably need additional motors to at least go up and down with this sub. My general goal is to make it neutrally buoyant without any additional mechanism for that so I could control it easily with motors, but there is also always an option of adding something like a syringe inside the sub which could effectively change the volume of the sub and by that change how buoyant it is. Some key notes for the sub are:

• BLDC motors - due to their design, BLDC motors are actually waterproof, though they should always be cleaned and dried after getting wet because of things like bearings.
• Camera & Light - In the front I want to have a small camera and a ring light around it, but this will also require a transparent front plate 
• Fins - fins are a great way of steering the sub when we’re moving, but since the sub will be stationary a lot to, to move around in that environment, adding an axis for rotating the thrust BLDC motors will make the sub way easier to maneuver
• Data cable - This is something that will of course be needed to control the sub.

3. Plan

Now that I’ve explained the idea behind this project, what’s my plan for the realization? I’m currently working on getting the starter kit through customs, so I’ll begin work as soon as it arrived, my plan is to first look at all of the connectors from the kit and check what I could use where and go from there. The most critical part of this project is the sub itself of course, and I’ll need to do a lot of testing to make sure that the enclosure if waterproof before I start putting electronics in it. One potential problem are the rotation axis for the thrust motors, since I’ll need to either waterproof the axis itself or waterproof servo motors and keep them in the water as well. During research, I’ve found that both are doable, it’s just the question of what’s easier to do and what will give better results.

4. Summary

This was a shorter blog where I just wanted to present my idea for this project. I went over the whole system and talked about the things I think are important on it as well as the things that I think will become a challenge as I start working on it. My goal is to by the end of this design challenge to have a small sub that I can pilot and drive around using my laptop. If I manage to do that without damaging any of the electronics inside, I’ll be happy since that will mean I’ll have a platform from which I can build and expand to do whatever kind of missions I desire. As soon as I get the kit, I’ll be posting a blog about going through all of the parts and seeing what I could use where. Thanks for reading the blog, hope you liked it!

Milos