❤️ Heart Rate and HRV Monitor (Raspberry Pi Pico + Kubios Cloud)

A real-time heart rate (HR) and heart rate variability (HRV) monitor built on the Raspberry Pi Pico, using MicroPython, OLED visualization, and Kubios Cloud for advanced analytics.

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🩺 Features

• Real-time ECG/PPG sampling via ADC (GPIO 26, 250 Hz)
• On-device HRV computation:
  meanHR, meanPPI, SDNN, RMSSD, SD1, SD2
• OLED display with live signal and menu navigation
• Rotary encoder input with push-button control
• LED pulse indicator synchronized with heartbeat
• Wi-Fi integration for Kubios Cloud readiness analysis
• Persistent JSON storage for session history
• Error feedback on OLED for network or sensor faults

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System Overview

        ┌──────────────┐
        │  PPG Sensor  │
        └──────┬───────┘
               │ ADC (26)
        ┌──────┴───────┐
        │ Raspberry Pi │
        │     Pico     │
        └──────┬───────┘
     ┌─────────┴─────────┐
     │ Signal Processing  │ → HR + HRV
     └─────────┬─────────┘
               │
   ┌───────────┴────────────┐
   │ OLED Display / Encoder │
   └───────────┬────────────┘
               │
          Kubios Cloud

Hardware Setup

Component	GPIO	Function
PPG/ECG Sensor	26	Analog input
OLED (SSD1306 I²C)	SDA = 14, SCL = 15	128×64 display
Rotary Encoder A/B	10 / 11	Menu rotation
Encoder Button	12	Selection
PWM LED	21	Pulse feedback
Onboard LED	"LED"	Status indicator
Power: via USB 5 V
Sampling Rate: 250 Hz
Display Refresh: ~25 Hz

Menu Navigation

Use the rotary encoder to scroll and press the button to select.

Mode	Description
Measure HR	60 s sampling, computes HR + HRV metrics
HRV Analysis	Displays results on OLED
History	Shows last saved session
Kubios	Uploads RR data for cloud analysis

Example Outputs

OLED Display

MeanHR: 73 bpm
SDNN: 41 ms
RMSSD: 28 ms
SD1: 20  SD2: 55

Serial Console

--- Kubios HRV Summary ---
Mean HR: 72.6 bpm
SDNN: 41.2 ms
RMSSD: 27.8 ms
PNS Index: 0.65
SNS Index: -0.42
Readiness: 7.9

HRV Metrics

Metric	Description
SDNN	Standard deviation of NN intervals
RMSSD	Root mean square of successive differences
SD1 / SD2	Poincaré plot short/long term variability
PNS / SNS index	Parasympathetic & sympathetic balance

Skills Demonstrated

• Embedded systems design
• Real-time signal acquisition
• HRV time-domain analysis
• OAuth2 + REST API integration
• I²C, ADC, PWM, interrupt-driven input
• MicroPython async and timer programming

License

Distributed under the MIT License. See LICENSE for details.