https://github.com/parikshitsah/pulse_oximeter
A pulse oximeter for Raspberry Pi Pico W using MAX30103 and BLE
https://github.com/parikshitsah/pulse_oximeter
ble bluetooth-low-energy micropython micropython-rpi-pico pico-w raspberry-pi raspberry-pi-pico rp2040
Last synced: about 15 hours ago
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A pulse oximeter for Raspberry Pi Pico W using MAX30103 and BLE
- Host: GitHub
- URL: https://github.com/parikshitsah/pulse_oximeter
- Owner: ParikshitSah
- Created: 2025-04-17T21:50:23.000Z (2 months ago)
- Default Branch: main
- Last Pushed: 2025-05-12T16:04:32.000Z (about 2 months ago)
- Last Synced: 2025-05-12T17:25:27.381Z (about 2 months ago)
- Topics: ble, bluetooth-low-energy, micropython, micropython-rpi-pico, pico-w, raspberry-pi, raspberry-pi-pico, rp2040
- Language: Python
- Homepage:
- Size: 245 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Pulse Oximeter with BLE for Raspberry Pi Pico W
**Author:** Parikshit Sah
**Date:** May 5th, 2025
---
## Overview
This project implements a wireless pulse oximeter using the MAX30101 sensor and a Raspberry Pi Pico W. It reads SpO2 (blood oxygen saturation) and pulse data, processes the signals, and transmits the results over Bluetooth Low Energy (BLE) to a mobile device or computer.
- **SpO2 and BPM Calculation:** Signal processing and peak detection are used to compute SpO2 and heart rate (BPM).
- **BLE Transmission:** Results are sent wirelessly using a custom BLE health service.
- **MicroPython:** All code is written for MicroPython running on the Pico W.
### Developed Pulse Oximeter
### Sample IR readings
)](https://github.com/ParikshitSah/pulse_oximeter/blob/979a6c61def44bd23dcdfe8769e3357dd3f3bac2/sample%20readings/steph%20white%20finger.png)
---
## Directory Structure
```
├── ble_test.py
├── lib
│ ├── ble_advertising.py
│ ├── ble_health.py
│ └── oximeter.py
├── main.py
├── README.md
├── Steph finger white.png
└── steph white finger.png
```
---
## File Descriptions
### main.py
- Runs the main oximeter routine.
- Reads data from the MAX30101 sensor, processes it, and calculates SpO2 and BPM.
- Sends average SpO2 and BPM over BLE after every 4 readings using the BLEHealthService.
> **Note: The program currently uses custom (non-standard) BLE Service and Characteristic UUIDs, not the official Bluetooth SIG Pulse Oximeter UUIDs.**
### ble_test.py
- Example script to demonstrate the BLE health service.
- Sends random SpO2 and BPM values over BLE for testing.
### lib/oximeter.py
- Handles I2C communication with the MAX30101 sensor.
- Implements signal processing: DC removal, moving average, peak detection, SpO2 and BPM calculation.
### lib/ble_health.py
- Implements a BLE service with custom characteristics for SpO2 and BPM.
- Handles BLE advertising, connections, and notifications.
### lib/ble_advertising.py
- Helper functions for building BLE advertising payloads.
---
## Hardware Requirements
- Raspberry Pi Pico W
- MAX30101 Pulse Oximeter Sensor
---
## Usage
1. **Flash MicroPython** onto your Pico W if not already done.
2. **Copy the repository files** to your Pico W (using Thonny, rshell, or similar).
3. **Connect the MAX30101 sensor** to the Pico W via I2C (default: SDA=16, SCL=17).
4. **Run `main.py`** to start reading and broadcasting SpO2/BPM.
5. **Use a BLE app** (e.g., nRF Connect) to scan and connect to the device. Look for `PicoW_Oximeter`.
6. **Optionally, run `ble_test.py`** to test BLE functionality with random data.
---
## Signal Processing & Calculation
- **Moving Average Filter:** Smooths the raw IR/RED signals.
- **Peak Detection:** Identifies heartbeats in the filtered signal.
- **SpO2 Calculation:** Uses the ratio of ratios method from [DOI 10.1088/0967-3334/27/1/R01](https://iopscience.iop.org/article/10.1088/0967-3334/27/1/R01)
- **BPM Calculation:** Based on the average interval between detected peaks.
---
## Customization
- Adjust sample window, filter size, and thresholds in `main.py` and `oximeter.py` for your use case.
- BLE device name and advertising interval can be set in `main.py` and `ble_health.py`.