Seán Maher

2024 · Lead Mechanical

Shooter Design & Autonomous

In 2024, my responsibility included the full shooter subsystem, design and manufacturing. I designed the shooter to be easy to manufacture using our sponsors waterjets and off the shelf components. There was little room for revision due to the tight schedule, causing the project to rely heavily on early prototyping and simulations

The shooter used an offset-wheel mechanism I developed to handle two targets with one system. Offsetting the wheels puts spin on the game piece at high RPM to reach the far target, while holding enough control at low RPM to place into the near one. It is not in the CAD above; it appears in the photos of the built robot.

I also helped write the robot's autonomous routines and planned the routes and strategy behind them, contributing to our team's Autonomous Award at the World Championship. The season became the team's most successful, with five event wins, including the Pacific Northwest District Championship, and a fourth-place finish in our Worlds division as an alliance captain.

2025 · Lead Mechanical

Elevator, Pivot & Intake

I led the mechanical design of three interconnected subsystems: a two-stage cascading elevator, an end-effector pivot, and a dual-capability roller intake. The central challenge was packaging the assembly to fit within the robot's starting configuration while providing the reach needed for scoring.

I also co-led the fabrication of components. Another student and I programmed the toolpaths in Fusion CAM and machined all of the robot's CNC parts, and I . Making the parts I designed shaped my approach: I reduced setups and machining operations and sized features around the tooling we owned.

The pivot was the tightest part of the assembly. A single hex shaft runs through six press-fit bearings, so every part in that stack had to hold manufacturing tolerance well under 0.050 in for the shaft to go together at all.

Half way through the season we found that the intake I had originally designed, while usable, was not ideal. It cost us cycle time and broke more often than it should have. I redesigned it mid-season, and the CAD shown here is that second design rather than the one we started with. The pit photo above predates the change.

2025 Off-Season · Independent

Complete Robot Design

I independently designed a complete competition robot in Fusion 360, from chassis through an internally belted custom elevator, with no outside CAD contribution. Taking responsibility for the full robot pushed me beyond the subsystems I had owned during the regular season. Every mechanical decision and every interface between mechanisms was mine to resolve.

The project changed how I approached robot design. Decisions within one subsystem affected the space and geometry available to the next, so I had to consider each mechanism as part of the complete assembly. Owning the entire design exposed integration challenges I had previously relied on teammates to work through and made this my clearest example of independent engineering work.

It came to roughly 200 to 250 hours and between 300 and 500 fully custom parts. Two things I would redraw. I would open up access to the electrical system, and I would change the direction the frame chassis support bar runs so the climber mounts properly into the structure. Climbing was not an original goal and was added after the fact, and the design shows it.

2026 · Lead Mechanical

Full Robot Design & Integration

In my final FRC season, I designed the drivetrain, intake, hopper, and indexer, including the interfaces connecting them to a shooter designed by another teammate. Within a six-week build season, my central challenge was keeping game pieces moving reliably through the robot. Each piece passed through four handoffs before exiting, and every transition was a potential jam point. Those interfaces became a primary focus of my design work. I used transparent polycarbonate guides to minimize friction and optimize for passthrough time and weight.

The original intake and hopper failed at our week one competition. I redesigned both systems entirely in three days, then machined and rebuilt practically the whole robot other than the shooter and turret over five days total. The design that came out of it holds fewer than ten game pieces rather than relying on a large hopper, and we measured a peak of 16 pieces per second moving through it.

Fusion CAM · CNC Router

From CAD to Chips

These are parts from the robots above, cut from 6061 plate on the team's CNC router. I wrote the toolpaths in Fusion CAM and ran the machine, then taught other members to write toolpaths and run it so the team was not dependent on one person to make parts.

2026 · Mechanical Design & Fabrication

EcoStep · Modular Prosthetic Leg

I designed and fabricated a modular pediatric prosthetic leg prototype targeting a parts cost below $100 and approximately 30° of knee flexion. I owned the mechanical design and fabrication, and developed the firmware with a teammate. The project combined replaceable printed components with a mechanical joint and haptic feedback system.

The joint went through three architectures. My first design used a TPU flex pin, but it was too rigid to provide useful motion. A slotted version allowed twisting but fractured under shear. For the third iteration, I replaced the compliant pin with a bronze bushing, aluminum spacer, and return spring. Each prototype answered a specific question, and its failure informed the next design. Across those three architectures I printed more than fifteen versions of the joint, not counting the material tests.

I then compared materials, infill densities, and infill patterns through load testing. The selected CF-ABS configuration, printed at 50% gyroid infill, deflected 2.48 mm at 100 lbf and reached a reported failure load of 205 lbf. Its most meaningful result was how it failed: testing recorded 8.5 mm of deformation before fracture, shifting the behavior from abrupt snapping toward progressive deformation. Stress analysis also guided reinforcement of the bridge between the bushing and housing and a change in print orientation.

A Raspberry Pi Pico W, VL53L0X time-of-flight sensor, and a coin vibration motor in the socket provided step detection and tactile feedback. All testing was on the bench; science fair rules prohibit human testing, so the leg was never fitted to a person.