PRESCO SHIELD – WRIST BAND
Monitoring Wristband for Sleep, Heart Rate, and Activity
CATEGORY
- IoT
- Medical Devices
- Patient Monitoring
Bharat Narhari
NeuralBits Private Limited (Mumbai)
SERVICES
- Feasibility & Product Design
- Full-Cycle Product Design
- Hardware & PCB Design
- Mechanical Design
- Firmware Development
- EVT, DVT, PVT
PROJECT TIMELINE
THE CHALLENGE
NeuralBits tasked Axio Electronics to develop the Presco Shield: a wrist-worn 'BLE Beacon' for continuous patient monitoring in hospital settings—no tethered cables or bedside units. Critical requirements included: Compact, durable form factor comfortable for 24/7 wear and frequent disinfecting. Multi-parametric sensing: heart rate & SpO₂ via MAX32664C FDA-certified algorithm, skin temperature, 3-axis IMU activity tracking. External SPO₂ support through AFE4490 for Nelcor-style finger sensors. Seamless connectivity: BLE for local nurse-station updates, Wi-Fi for cloud integration. Extended autonomy: one-month continuous operation on a single charge. Modular expandability: external BP cuff integration, onboard microphone & buzzer for patient prompts, NFC tag for zero-touch device registration. Regulatory compliance: medical-grade materials, IP67 sealing, IEC 60601 electrical safety.
- Form Factor: Compact, durable, comfortable for 24/7 wear and frequent disinfecting.
- Sensing: HR & SpO₂ (MAX32664C), skin temp, 3-axis IMU, external SPO₂ (AFE4490).
- Connectivity: BLE for nurse-station, Wi-Fi for cloud.
- Battery: One-month continuous operation.
- Expandability: BP cuff, microphone, buzzer, NFC tag.
- Compliance: Medical-grade, IP67, IEC 60601.
KEY HURDLES
- •Preventing cross-talk between high-voltage sensing (AFE4490) and low-level sensor channels.
- •Minimizing power draw from high-resolution sensing and dual-radio operation without sacrificing uptime.
- •Designing a strap & enclosure that endures hospital cleaning protocols.
- •Achieving reliable NFC registration through fabric and gown layers.
- •Certifying sensor accuracy to FDA and CE requirements for vital-sign monitoring.
THE OPPORTUNITY
Manual vital checks interrupt patients and consume nursing resources. Presco Shield promised to:
- Free nurses for higher-value tasks by automating routine checks.
- Provide early warning of patient deterioration (e.g., hypoxia, fever spikes).
- Reduce cross-infection risk by minimizing direct patient-staff contact.
- Deliver rich longitudinal data for post-discharge follow-up.
FEATURE SETS
- •MAX32664C HR & SpO₂ – FDA-certified on-chip algorithm
- •Skin Temp Sensor – ±0.1 °C accuracy
- •3-Axis IMU – Activity & fall detection
- •AFE4490 Interface – Support for external Nelcor SPO₂ finger clip
- •BLE 5.2 & Wi-Fi Sync – HIPAA-compliant data upload to cloud portal
- •1-Month Battery – 2,500 mAh with smart power management
- •BP Cuff Integration – Paired Bluetooth cuff for on-demand checks
- •Microphone & Buzzer – Audio prompts & alarm notifications
- •NFC Tag – Automatic asset registration & patient pairing
- •IP67 Sealing – Dust- and water-resistant for cleaning
GALLERY
THE SOLUTION
Axio Electronics delivered a full-stack solution for Presco Shield, integrating FDA-certified sensors, robust wireless connectivity, and hospital-grade durability.
MAX32664C Algorithm
FDA-certified HR & SpO₂ processing on-chip
Temperature Sensing
High-accuracy skin-contact sensor
IMU Activity Tracking
3-axis motion sensing for steps, posture, fall detection
AFE4490 External SPO₂
Support for standard Nelcor finger-clip pulse oximeters
BLE & Wi-Fi Connectivity
Nurse-station BLE updates & hospital-Wi-Fi/cloud sync
30-Day Battery Life
2,500 mAh Li-ion with power-save modes
BP Cuff Integration
Paired Bluetooth cuff for intermittent blood-pressure checks
Microphone & Buzzer
Patient prompts, audio alarms, two-way clinician-patient cues
NFC Auto-Registration
Tap-to-pair with hospital asset and patient records
Medical-Grade Sealing
IP67-rated polycarbonate + silicone overmold
OUR APPROACH
Mechanical Engineering Strategy
Ergonomic Strap & Housing: Soft silicone overmold, quick-release clasp for cleaning.
Disinfecting Durability: Polycarbonate shell engineered for hospital-grade wipes.
Thermal Management: Internal graphite spreader for even heat dissipation.
Modular Ports: Sealed connectors for optional BP cuff cable.
Mechanical Engineering Process
CAD ergonomic studies with nursing-staff feedback
SLA prototypes for fit and comfort trials
Tensile and IP54 ingress trials on final overmolded samples
Final mold tooling for ABS and TPU parts
PCB & Hardware Design
Sensor Integration: MAX32664C, digital temperature die, MPU-6050 IMU
AFE4490 Front-End: High-precision analog path for external SPO₂
Power Management: TI PMIC with buck-boost regulators and fuel gauge
Radios: Nordic nRF52840 (BLE) & ESP32-C3 (Wi-Fi)
Audio: MEMS microphone, piezo buzzer driver
NFC: NXP NTAG for secure pairing
Safety Features: Medical-grade isolation, reverse-polarity protection, EMI filters
Firmware Design
Multi-Sensor Fusion: Synchronized HR, SpO₂, temp, IMU data at 1 Hz for cloud analytics
Power-Save Scheduler: Adaptive sampling rates based on activity levels
FDA Algorithm Calibration: Real-time quality indices and data-flagging
BP-Cuff Driver: BLE pairing & cuff-on-demand workflow
Audio Workflow: Stored prompts & alarm tones in flash
NFC Provisioning: One-tap asset & patient registration in hospital EHR
Secure OTA: Signed firmware and encrypted rollback protection
In-House Prototyping & Validation
Fit & Finish: Five SLA units worn by clinicians for 48 hr trials
Bench Testing: Sensor accuracy vs. gold-standard devices; Wi-Fi range in ward layout
EVT: Verified IEC 60601-1 safety, IP67 sealing, sensor specs
DVT: Two-week pilot on 20 patients—refined strap tension and UI prompts
PVT: 100-unit pre-production run with full factory QC
Key Challenges & Resolutions
- Motion Artifact in SpO₂— Enhanced signal-processing filter on MAX32664C
- Radio Coexistence— Time-division scheduler between BLE & Wi-Fi tasks
- NFC Read Failures— Increased antenna gain and firmware-driven retry logic
- Battery Leakage— Added secondary protection diode and cell balancing
PILOT & PRODUCTION
PILOT & PRODUCTION
Hospital Pilot: 50 beds across two wards for 30 days—100% uptime, zero adverse events. Workflow Impact: 75% reduction in manual vital checks, 20% faster response to alarms. BOM Optimization: 18% cost savings via alternate PMIC supplier. Regulatory: CE-Marked; FDA 510(k) submission in progress. Manufacturing Test Fixture: Automated checks for sensor calibration, radio power, battery capacity.
Hospital Pilot: 50 beds, 30 days, 100% uptime, zero adverse events
Workflow Impact: 75% reduction in manual vital checks, 20% faster response to alarms
BOM Optimization: 18% cost savings via alternate PMIC supplier
Regulatory: CE-Marked; FDA 510(k) submission in progress
Manufacturing Test Fixture: Automated checks for sensor calibration, radio power, battery capacity
How It Works
Wear the Presco Shield and secure the strap
Tap NFC on hospital tablet to pair with patient record
Continuous Monitoring of vitals & activity
Automatic Alerts via BLE to nurse station and Wi-Fi to cloud
Optional BP Cuff for on-demand checks, synced instantly
WHAT CAN
WE CREATE
TOGETHER
DOWNLOAD THE PRESCO SHIELD CASE STUDY (PDF)
Client Testimonial
Bharat Narhari
NeuralBits Private Limited
Axio Electronics delivered a flawless wearable solution—sensor accuracy met clinical standards, battery life exceeded expectations, and deployment in our Mumbai hospital was seamless.
Axio Electronics