CurlRing

> Overview

CurlRing translates the skip's curling commands into visual cues for sweepers using a handheld ESP32-C6 transmitter and a broom-mounted ESP32-C6 receiver. Instead of relying on spoken commands, the receiver displays immediate RGB LED patterns that can stay within a sweeper's natural field of view during play.

> Accessibility problem

Curling depends on fast communication between the skip and sweepers, but deaf and hard-of-hearing athletes may need alternatives that do not force them to stop sweeping or look away from the stone. CurlRing was designed around real-time visual recognition so commands can be received while the athlete stays engaged in the motion of play.

> System architecture

• The skip transmitter reads five physical command buttons, debounces and validates input, then sends encoded commands over ESP-NOW.
• The sweeper receiver listens for ESP-NOW packets and maps each command to a color and geometry pattern on a 12-segment RGB LED ring.
• Full-ring patterns represent commands for both sweepers, while partial-ring patterns communicate directional instructions.
• The end-to-end workflow is button input to wireless packet to receiver interpretation to visual sweeping instruction.

> Hardware and enclosure work

• Integrated two ESP32-C6 Supermini boards, tactile buttons, addressable RGB LEDs, battery power, and custom physical enclosures.
• Supported soldering and assembly for the transmitter and receiver electronics.
• Fabricated and assembled the broom-mounted receiver enclosure, including the clamping/mounting approach used to keep the display visible during sweeping.
• Helped validate practical details such as wrist retention, transmitter usability, and receiver stability during broom movement.

> Low-power design

Power optimization was part of the embedded design rather than a final polish step. The transmitter uses light-sleep behavior and short active transmission periods, while the receiver reduces CPU frequency, limits LED brightness, and turns LEDs off after inactivity so the system remains practical across multiple games.

> Testing and validation

• Measured transmitter current and estimated approximately 116.5 hours of runtime from a conservatively derated 800 mAh battery.
• Measured receiver current after optimization and estimated approximately 15.63 hours of runtime, or about six 2.5-hour curling games per charge.
• Validated ESP-NOW communication across the University of Manitoba atrium, from the sixth floor to the main floor.
• Performed ergonomic, drop/safety, shake, and end-to-end tests covering button input, wireless transmission, receiver updates, and LED command display.

> My contribution

• Contributed to hardware integration and electronics assembly for the transmitter and receiver.
• Worked on embedded power optimization and power-management behavior for the devices.
• Handled receiver enclosure fabrication, receiver assembly, transmitter testing, and end-to-end validation.
• Performed power-consumption testing and helped present the final system.

> Things learned

• Accessibility-focused embedded systems need to account for the user environment, not just the electronics.
• Low-power behavior has to be measured and validated because small firmware decisions can strongly affect battery-life estimates.
• Physical reliability matters as much as wireless reliability when hardware is mounted to equipment that is actively moving.