CLABSI

Handheld C-Line Hub Disinfection Device to Prevent CLABSIs (Central Line Associated Bloodstream Infections)

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Overview

CLABSI is a handheld medical device that disinfects central-line (C-line) hubs using UVC light. The device uses hardware interlocks to ensure safe operation and provides audible and visual feedback throughout the disinfection cycle.

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Repository Structure

CLABSI/
├── CAD/               # Mechanical enclosure (Onshape)
├── Firmware/          # Zephyr RTOS application (nRF54L15)
│   ├── application/   # Main application source
│   └── external/      # nRF Connect SDK, Zephyr, MCUboot submodules
└── KiCad/             # PCB designs
    ├── CLABSI (FINAL)/   # Final rev — schematic, layout, BOM, Gerbers, STEP
    ├── CLABSI (Midterm)/ # Midterm revision
    └── Exports/          # Gerber zips ready for fab (Base, Main, UVc)

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Hardware

PCBs

Three boards make up the device:

Board	Description	Gerbers
Main	Primary controller, power, BMS, RGB LED	KiCad/CLABSI (FINAL)/Individual Gerber/Main/
UVC	UVC LED driver board	KiCad/CLABSI (FINAL)/Individual Gerber/UVc/
Base	Mechanical base / connector board	KiCad/CLABSI (FINAL)/Individual Gerber/Base/

Fab-ready Gerber zips are in KiCad/Exports/.

3D STEP models are in KiCad/CLABSI (FINAL)/3dPCB models/.

Interactive BOM: KiCad/CLABSI (FINAL)/ibom.html

Key Components

• MCU: Seeed Studio XIAO nRF54L15
• BMS: Analog Devices MAX17260 (ModelGauge m5 fuel gauge)
• RGB LED driver: TI LP5815 (I2C)
• UVC LED: PWM-driven, controlled via Main board
• Buzzer: PWM-driven
• Interlocks: 2× mechanical switches for safety abort

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Firmware

Built on Zephyr RTOS with the nRF Connect SDK. The application runs a hierarchical state machine (Zephyr SMF):

INIT → IDLE ──► DISINFECTING ──► IDLE
            └► CHARGING      └► (abort via button or interlock)
            └► ERROR

State	Behavior
INIT	Initialize peripherals (GPIO, PWM, I2C, BMS, safety)
IDLE	Waiting for button press; shows battery SOC via RGB LED
CHARGING	Charging detected; indicates charge status via RGB LED
DISINFECTING	UVC LED on at full PWM; aborts instantly if either interlock opens or button pressed
ERROR	RGB LED error pattern + buzzer; cleared by button press

Safety: both interlocks must remain closed throughout disinfection. Any interlock open triggers an immediate PWM shutoff via an ISR-submitted work item before the state machine transition completes.

Building

Requires nRF Connect SDK and west.

west build -b xiao_nrf54l15 Firmware/application
west flash

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License

TBD

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Last Updated 2026-05-12 by @Nick-Trigger