Product Design / Hardware / HCI

OPENGYM

Making invisible patterns of movement visible.

Year: 2026 / Ongoing
Role: Product Designer / Hardware
Team: Business Technology Group
Context: CMU campus fitness facilities

At CMU, finding time to exercise shouldn’t mean finding time to wait.

78% of surveyed students experience moderate-to-heavy crowding, while over 90% of gym traffic converges on the Cohon University Center Fitness Center.

OpenGym counts and predicts occupancy across campus gyms in real time. I contributed to user research, enclosure prototyping, deployment, and performance analysis.

Problem→Research→System→Prototype→Deploy→Learn→Redesign

01.1 / System

A PHYSICAL TRIPWIRE.
A DIGITAL SIGNAL.

A laser and receiver positioned across an entrance detect directional movement, sending occupancy data through back-end servers to OpenGym’s interface.

Yellow-to-blue entry and blue-to-yellow exit detection diagram

01.2 / Iterative Prototyping

FIVE BUILDS.
ONE CONTINUOUS TEST.

Five hardware builds moved the sensor from a Lego proof of concept to a compact enclosure. Each version tested accuracy, stability, concealment, and maintenance.

V1 OpenGym occupancy sensor prototype — Lego-based proof of concept testing the core laser and receiver system.

V2 OpenGym occupancy sensor prototype — Compact enclosure integrating a functional laser and receiver.

V3 OpenGym occupancy sensor prototype — Refined receiver geometry increased sensitivity and reduced detection errors.

V4 OpenGym occupancy sensor prototype — Concealment strategies tested how the device could remain unobtrusive during everyday gym use.

V5 OpenGym occupancy sensor prototype — A 3D-printed enclosure reduced unintended laser movement.

01.3 / Deployment

THE GYM
BECAME THE LAB.

The final prototype was deployed at the Cohon University Center Fitness Center. Physical placement, alignment, and everyday student activity became part of the research.

Cohon University Center fitness facility entrance used for deployment — Deployment site / Cohon University Center

OpenGym laser unit mounted beside a gym entrance — Laser unit

OpenGym receiver mounted opposite the laser — Receiver unit

01.4 / Real-world Learning

BUILD → DEPLOY
OBSERVE → LEARN

Controlled tests could not reveal every way the enclosure would be touched, shifted, opened, or maintained.

Laser movement

Small shifts disrupted alignment.

Enclosure size

The receiver needed to occupy less visual and physical space.

Maintenance

Hardware had to detach and reassemble without disturbing the setup.

Accidental interaction

The enclosure needed to protect the device during everyday use.

01.5 / Designing V6

DESIGNING
V6.

V6 addresses three problems found during deployment: an oversized receiver, lids that were difficult to service, and a laser that shifted out of alignment. The redesign reduces receiver volume by 40%, uses slide-lock lids, and adds a snug-fit stabilizer.