For our ENGR 499 capstone, our team partnered with the Okanagan Basin Water Board (OBWB) to support non-chemical mitigation of Eurasian watermilfoil in Okanagan lakes.
The challenge was straightforward: rototilling operators have limited visibility below the waterline, which increases collision risk, substrate guesswork, and redundant passes. The objective was to integrate the Delta Vision HD underwater camera through a mounting system that was robust, practical, and safe to use in real operations.
Problem Context
OBWB avoids herbicides in these potable water sources and relies on mechanical control methods. That made operator visibility and efficiency a high-value improvement area:
- Better obstacle detection near the rototiller arm
- More confidence in substrate identification and penetration depth
- Fewer unnecessary repeat passes and lower turbidity generation
What We Built
The final system was a universal magnetic camera mount assembly using:
- Dual 95 lb ceramic ferrite magnets
- PETG 3D-printed connector body at 30% infill
- RAM ball mount components and clamp interface
- Integrated pry slot for easier and safer removal
We also evaluated a 1.0 mm nitrile O-ring concept as future refinement to increase friction at the hull interface without compromising magnetic coupling.
Iteration Path
1) GoPro Field Feasibility Test
Before final hardware design, we performed a live proof-of-concept by mounting a GoPro to the rototiller arm on Wood Lake. Even with turbidity, footage validated that useful visibility could be maintained above the disturbance cloud.
2) Fixed Bracket Concept (Rejected)
An early welded bracket concept offered rigidity, but failed practical requirements. It lacked universality across equipment, increased fabrication burden, and introduced permanent modification concerns.
3) Single-Magnet Prototype
The first physical magnetic prototype held strongly in normal direction, but rotated under off-axis loading (drag, vibration, cable tension). That rotational instability was a critical failure mode.
4) Dual-Magnet Prototype and Final PETG Design
Dual contact points solved the rotational issue and significantly improved stability. We then transitioned from PLA to PETG and added a pry slot to improve operator usability during removal.
Testing Highlights
- Water absorption test on PETG sample: no measurable mass or dimensional change over 48 hours in freshwater
- Cold exposure test: no cracking or deformation after 48 hours in freezing conditions
- Slide resistance test: mount held up to 60 lb perpendicular shear load before slipping
Engineering and Ethics
This project was not only about mechanism design. It required balancing safety, maintainability, environmental responsibility, and client usability.
Key considerations included:
- Compatibility with OBWB’s non-chemical policy and potable water context
- Material and component selection for long-term reliability in wet environments
- Risk management through iterative testing and client feedback
- Clear documentation for future improvement and deployment
Outcome and Next Steps
The final mount met the practical direction set by the client and created a platform for further development. Some long-interval criteria (for example, annual collision reduction targets) require full-season deployment data after project closeout.
Future upgrades discussed with the client included:
- Integrated lens cleaning approach
- Offshore data transmission/recording workflow
- Lighting or infrared-assisted underwater visibility
This capstone reinforced a core lesson: the best engineering outcomes come from iterative design under real constraints, with field feedback guiding each decision.