2024–2025 Competitive Robotics v3 — Current

High Stakes Competition Robot

A sub-18-inch VEX V5 competition robot, designed and built solo for the 2024–2025 High Stakes season — and the power take-off behind its climb.

VEX V5 Mechanism Design Fabrication

Final v3 competition robot, three-quarter view. — The final v3 configuration: integrated wall-stake mechanism, PTO climb, and ring launcher.

01 — Overview

One robot, four unrelated jobs, and a fixed 88-watt budget to split between them.

A sub-18-inch VEX V5 competition robot, designed and built solo for the 2024–2025 High Stakes season. It scores rings on goals and stakes, scores on elevated wall stakes, and climbs a center ladder for endgame elevation, all within an 88-watt total motor budget. Its defining feature is a power take-off (PTO) that reuses the drive motors to power a winch climb, freeing motor budget for scoring instead of spending it on a dedicated climb system.

Power budget

88 W

Drive

450 RPM

Start volume

18³ in

Climb

Tier 3

Skills score

57 10th in region

02 — Problem

High Stakes rewards robots that can do several unrelated jobs well: collect and place rings, score on elevated wall stakes, manipulate mobile goals into scoring corners, and climb a ladder at the buzzer. The core engineering tension is that VEX caps total motor power at 88 W and starting size at 18 in³, so every motor spent on one capability is a motor not available for another.

The design problem was less "can I build a mechanism" and more "how do I allocate a fixed power and space budget across four competing subsystems without compromising any of them."

03 — Requirements

Separating the rules I was given from the targets I chose, and the numbers that fell out of those choices.

Fixed constraints from the game manual

Constraint	Limit
Starting volume	18 × 18 × 18 in
Total motor power	88 W
Brains	1
Custom plastic	Must nest in one 12 × 24 in × 0.070 in non-shattering sheet
Pneumatics	2 tanks, 100 psi max
Possession	2 rings + 1 mobile goal at a time

Chosen design targets my decisions

Choice	Value	Rationale
Drive speed	450 RPM	Balance of top speed vs. acceleration (decision-matrix winner over 350 / 600)
Wheel	3.25" omni	Best speed/torque trade for chassis weight
Climb method	PTO winch	Climb without dedicated motors, keeping power budget for scoring
Wall-stake arm	67 RPM, 1 motor	Fast scoring cadence, minimal power draw

Measured / derived outcomes what the choices produced

Quantity	Result
Driver skills score	41
Autonomous skills score	16
Combined skills	57 (10th in region)
Max theoretical score / attempt	44

Weighted decision matrix from the engineering notebook. — A weighted decision matrix from the notebook: systematic selection, not preference.

04 — Design

I decomposed the build into independent subsystems and selected each with a weighted decision matrix rather than by preference. Chassis configuration, intake, scoring arm, mobile-goal clamp, and elevation were each scored against the criteria before I committed.

Isometric CAD render of the complete robot.

Drivetrain — 450 RPM over 600 / 350

Considered350, 450, and 600 RPM, scored on acceleration and pushing power against gear and wheel ratios.

Chose450 RPM on 3.25" omni wheels.

Because600 RPM was faster but lost the pushing force needed to drive mobile goals into corners; 350 RPM was too slow for cycle time.

PTO climb — the signature decision

ConsideredA dedicated winch driven by its own motors, versus rerouting the drive motors.

ChoseA power take-off shifter (two metal spacers constrained by nylocks, a 12T metal pinion as the shift gear) that reroutes the drive motors to a two-stage winch for the Tier-3 climb.

BecauseIt buys back motor budget for scoring instead of spending it on climb.

Trade-offThe robot can't drive and climb at once, but climbing happens at the buzzer, so that cost is effectively free.

Intake → Lady Brown handoff

ChoseA 600 RPM two-stage hook intake feeding a 67 RPM wall-stake arm that passes off rings for scoring.

BecauseDesigning the geometry so the handoff is reliable, rather than two separate manual operations, was the integration challenge.

Custom plastic for DFM

ChoseAll structural POM/Delrin plates CAD'd to nest within a single 12 × 24 in sheet.

BecauseIt satisfies the inspection rule while keeping the laser-cutter workflow to one cut file.

Close CAD render of the PTO shifter: 12T pinion, nylocks, and washer stack. — The PTO shifter — the signature mechanism — showing the 12T pinion, nylocks, and washer stack.

Honest limitations The PTO adds mechanical complexity and a failure mode at the shifter; the single-motor wall-stake arm trades redundancy for power savings. Both were deliberate calls given the 88 W ceiling.

05 — Fabrication

I laser-cut the structural plates from POM (Delrin) using nested 12 × 24 in drawing files generated from my CAD. The PTO shifter, the most complex assembly, used thin washers between nylocks to eliminate metal-on-metal friction around the 12T pinion.

A mid-season fabrication constraint drove a real material change. With no laser-cutter access over winter break, and with steel rail shafts proving too heavy on the ring launcher, I swapped to rounded aluminum standoffs as carriage rails: a lighter solution that preserved low friction.

Nested laser-cut POM plates on the sheet. — Nested laser-cut POM plates: the whole structure off one cut file.

In-progress assembly of the robot. — Mid-build assembly.

06 — Testing

I validated the robot across four in-season tournaments, with each competition feeding the next iteration.

Driver skills

Auton skills

Combined

57 10th in region

Score ceiling

44 pts / attempt

Match data drove strategy refinement; the "screens" defensive play and corner-control offense were both validated through qualification matches.

What testing surfaced The robot capped at 44 points per attempt, a design-driven ceiling that set the target for the next iteration. The recurring weakness was driver practice and autonomous programming time, not the hardware: the mechanisms outpaced match execution.

The robot scoring during a skills run. — Scoring during a skills run.

07 — Iterations

How it evolved.

Each iteration was a competition-driven rebuild, not a tuning pass.

v3 Current 2025 · 03

Final integrated configuration

Integrated a dedicated wall-stake mechanism, refined the PTO elevation system, and added a single-use ring launcher to score the high stake during autonomous. Steel rails swapped to aluminum standoffs for weight.

Single-use ring launcher: 6-point bonus + autonomous-win-point contribution
Steel rails → rounded aluminum standoffs
Excellence Award (Stauffer, Feb) — top award at the event

Final config with ring launcher and integrated wall-stake mechanism.

v3 — ring launcher + wall stake

v2 Superseded 2024 · 12 – 2025 · 02

Mid-season rebuild

Directly addressed v1's missing wall-stake capability and added endgame elevation without spending extra motors.

Added the 67 RPM "Lady Brown" wall-stake arm
Motor-stacked the 6-motor drive for space
Routed the PTO into a two-stage winch for a fast Tier-3 climb

Robot 2 after the rebuild, showing the Lady Brown arm.

v2 — Lady Brown arm added

v1 Initial 2024 · 07 – 11

Initial competition build

PTO drivetrain, two-stage hook intake, scoring arm, and a pneumatic mobile-goal clamp. The design and notebook were strong, but the robot needed a wall-stake scorer as the metagame evolved.

450 RPM, 3.25" omni, H-frame drive with PTO
Design Award (Downey, Sept), Design Award (Legacy, Oct), Innovate Award (Downey, Nov)
Surfaced the gap: no wall-stake capability

Robot 1 as it competed, September to November.

v1 — initial build

08 — Outcomes

Results

Excellence Award, plus 2× Design and 1× Innovate across the season.
57 combined skills score, 10th regionally.
A reusable PTO architecture that delivered climb capability at zero dedicated-motor cost.

What I'd do differently

Budget driver-practice and autonomous-programming time as deliberately as motor power. The season's recurring bottleneck was execution time, not mechanism design.