Design Proposal

Problem Overview:

            Because collecting vital water samples for quality testing can be a particularly cumbersome task, the goal of this project is to devise a solution to maximize the ease of the water collection operation. Furthermore, collecting samples from particular depths can prove to be difficult, costly, and therefore, inefficient. Being able to efficiently procure water samples from specific depths of bodies of water is a necessity for researchers to determine whether measures should be taken to improve water quality.   The focus of this project is to create a remotely controlled submersible capable of adequately propelling itself through a body of water with or without a current, diving to specific depths, and collecting water samples for future testing.

 

Design Constraints:

            This submersible must be created using the apparatus provided, specifically the SeaPerch.  Also, it must be capable of remaining waterproof regardless of depth, propelling itself through water with and without current, and must be controlled remotely.  The submersible should also be capable of accurately determining depth as well as drawing samples accordingly.

Pre-Existing Solutions:

As the design stages continue, it is important to look at existing apparatuses that have a similar function to that desired of the finished SeaPerch in this project. There are many established ways of collecting water, which suit many different situations. For example, when collecting a water sample from the tap or from a stream, a clean and dry plastic water bottle is perfectly acceptable [1]. In the ocean, a device called a CTD is employed. CTD is an acronym for Conductivity, Temperature, and Depth [2]. The device, seen below, consists of a carousel of water bottles and various sensors that record the water conditions. These bottles are able to close remotely, which is a property that is crucial to the success of this project.

A CTD device [3]

The CTD’s use, however, is not conducive to the river environment that this project’s SeaPerch will be tested in. The “weapon” of choice for collecting samples in river environments is the US-D-96-A1 sampler. The US-D-96-A1, seen in the picture below, is a thirty-five inch, eighty pound, sampler with a hollow inside capable of holding a three-liter bag [4]. It functions by placing a plastic bag in the tray on the inside of the device. This plastic bag is connected to a nozzle that protrudes from the tip of the apparatus. The apparatus is lowered into the river so the nozzle is pointed against the current of river. The river’s current will then force water through the nozzle into the bag.

The US D-96-A1 sampler [5]

            It is important to remember moving forward that this project deals with a much more lightweight apparatus than is currently used. This will result in adjusting the sample size taken. That said, it is important that this project takes both the depth sensing capability of the CTD and the collection method of the US D-96-A1 sampler into account when the design is finalized.

 

Design Goals:

The goal of this project is to be able to take water samples from different depths using the SeaPerch remote controlled submersible device.  The original design is a basic frame with multiple propellers and an equal amount of motors.  The design task is determing in what manner to attach a syringe to the SeaPerch and how to trigger and mechanize the opening of the syringe.  This entails the introduction of a new motor with either a remote trigger or a depth sensing mechanism.  While the SeaPerch is meant to simply travel through the water, the proposed modification will be capable of taking water samples from specific depths.

Deliverables:

By the end of the 10-week term, the fully functional SeaPerch submersible will be assembled and ready for usage. A water-extracting apparatus capable of taking remote water samples will be designed, constructed, and attached to the SeaPerch submersible. A gear attached to a motor will open one or more syringes based on depth. The depth finder will be successfully attached and utilized in the triggering of open and closing of the syringe(s). These three components will be controlled with hand-held operators.

Project Schedule:

Week- Task

One- Create Blog

Two- Assemble SeaPerch Kit

Three- Research and Design Proposal

Four- Develop Modification Plan and Accompanying Designs

Five- Create Attachable Water Sampling Device

Six- Construct Modified SeaPerch

Seven- Test Design, Make Improvements

Eight- Reconstruction of Device

Nine- Final Test of Design, Prototype Completed

Ten- Presentation and Report Due

 

Projected Budget:

Table 1: A description of parts as well as the total cost of each part and of the parts as a whole is shown. Part names are hyperlinked to the locations where they could be purchased.

#	Part	Function	Quantity	Price Per Part	Total Price
1	Depth Finder	Determines the distance from the floor to the vessel	1	$49.99	$49.99
2	Motor	Used to open syringe	1	$115.00	$115.00
3	Syringe	Used to gather and hold water sample	4	$0.72 (+ S&H)	$7.82
TOTAL EXPECTED COST					$172.81

           It should be noted that there are a few alternatives available for each part. For example, the depth finder is the least expensive one on the market (that features what the project requires). There are other sources of depth finders: different brands of fish finders, like this depth finder is, and also one sold through the SeaPerch website. The other brands of fish finders really do not have any noticeable advantages; they are just more costly. The two distinct differences between the fish finders and the one sold through SeaPerch (HOBO sensor) are the price (HOBO sensor costs just under $500) and the reference point of the depth. The HOBO sensor measures how deep the unit is in relation to the surface of the water, whereas the fish finder determines how far away the unit is from the floor. Depending on the water being tested (ocean, lake, river, etc.) and the reason for testing, this difference may or may not be relevant. For the purposes of this project, it is sufficient to determine the SeaPerch’s distance from the river floor.

In addition to variances in depth finders, there are options for the type of syringes to buy. There are different kinds of syringes within the realm of plastic animal-feeding syringes. These are all about the same- there is no real reason to deviate from the syringes chosen. There are minor price differences between each of them and insignificant performance differences. The number of syringes needed is listed at 4. This number is the maximum that will be required in the project; however, at this stage of building, it is unknown whether the SeaPerch will be outfitted to gather one water sample or many.

SeaPerch motors can be purchased only in sets of 15 – they all come with the necessary parts to create thrusters out of the motors. As it stands, one or two of these 15 motors would be needed for this project. In order to view the details of the SeaPerch product, you must have a free SeaPerch account. Any additional parts necessary for the modified SeaPerch, such as attachment parts for the aforementioned devices can be constructed in the lab at little to no cost.