ENGR 499 Capstone Entry

OBWB Rototiller Camera Mount for Eurasian Watermilfoil Control

I contributed to a five-person capstone team that designed a universal underwater camera mounting system to improve safety, visibility, and operational efficiency for rototilling in Okanagan Basin lakes.

What, Why, and How

The Okanagan Basin Water Board (OBWB) manages invasive Eurasian watermilfoil using mechanical rototilling because chemical methods are not acceptable in these potable water sources. The operational challenge is that operators have limited underwater visibility, which increases collision risk, guesswork on substrate depth, and repeated passes that reduce efficiency.

Our objective was to design a robust mount for the Delta Vision HD underwater camera so operators could see the work zone in real time. We followed an iterative, client-driven process with field testing, prototype redesign, material validation, and risk review. The final concept was a dual-magnet PETG mount with a pry slot that improved rotational stability, maintained strong shear resistance, and made removal practical in day-to-day operation.

5

capstone team members on design and testing

60 lb

measured perpendicular shear load before slipping

$381.50

total project spend under a $500 budget

Non-Engineering Perspective

What This Means for Everyday Users

Safer Daily Operations

The camera gives operators real-time visibility near the rototiller arm, reducing blind operation and object-strike risk.

Better Use of Field Time

Seeing previous passes can reduce redundant runs, improving efficiency and helping crews cover more priority areas.

Environmental Alignment

The solution supports OBWB's non-chemical control strategy and targets better mitigation without introducing herbicide risk.

Engineering Perspective

System Decisions and Technical Tradeoffs

Magnetic Stability Problem

A single-magnet concept rotated under off-axis loads (drag, vibration, cable tension), so a dual-magnet geometry was adopted to resist torque.

Material Selection Validation

PLA was replaced with PETG after water absorption and freeze exposure tests showed PETG maintained dimensional and mass stability for immersion use.

Usability and Serviceability

A recessed pry slot was added so operators can break magnetic adhesion progressively, reducing removal effort and improving handling safety.

Design Evolution

Iteration Story: Concept to Prototype

Iteration 1

Field Feasibility with GoPro

We zip-tied a GoPro to the rototiller arm during active operation to verify underwater visibility above turbidity clouds and validate camera integration feasibility.

Iteration 2

Fixed Bracket Concept

An early welded-barge bracket was rejected because it reduced universality, increased fabrication burden, and introduced long-term chassis modification concerns.

Iteration 3

Single to Dual Magnet Prototypes

The single-magnet PLA housing showed rotational instability. A dual-magnet PLA design improved stability and demonstrated 60 lb slide resistance in load testing.

Iteration 4

Final PETG Dual-Magnet Mount

The final design used PETG at 30% infill with integrated pry slot and optional O-ring concept for friction augmentation while preserving magnetic coupling.

Multimedia Process Walkthrough

Key Artifacts with Context

Figure 1: Iteration Path

GoPro POC Feasibility test Fixed Bracket Rejected Single Magnet Rotational issue Dual Magnet Stable Final: PETG + Pry Slot Universal, robust, removable
Descriptive caption: Field testing and client feedback drove four major design stages from concept validation to the final deployable mount.

Figure 2: Performance Against Requirements

Requirement status from final report Visibility for substrate and milfoil assessment Strong prelim Slide resistance under side loading 60 lb test One-season collision reduction target Pending field season Target metrics requiring full-season deployment are documented as future validation work.
Descriptive caption: Bench and preliminary field evidence supported feasibility, while year-over-year collision reduction requires post-project operational monitoring.

Figure 3: Final Architecture

Dual Ferrite Magnets PETG Connector 30% infill + pry slot RAM Ball Base Camera Clamp Universal attachment without welded barge modification.
Descriptive caption: The final assembly combines commercial RAM components with a custom PETG housing and magnetic interface to enable flexible, removable deployment.

Figure 4: Risk and Ethics Snapshot

High-priority risks and mitigation themes tracked in final reporting.

User safety risk
Monitored
Environmental risk
Controlled
Scope and budget risk
Mitigated

Descriptive caption: The project maintained non-chemical environmental priorities while reducing delivery risks through structured scope control and client feedback loops.

Professional Framing

This project demonstrated that responsible engineering in public-water systems requires technical rigor and ethical rigor at the same time. We designed for safety, environmental compliance, maintainability, and client usability, not only for mechanism performance. The strongest result was a practical design the client can continue developing after the course.

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