Open Health Band Firmware
Firmware for Open Health Band
Description
This repository regroups all the firmware and tests which run on Open Health Band.
For hardware plans and schematics see movuino/OpenHealthBand. For the web BLE GUI see movuino/OpenHealthBandVisualization
Getting Started
Dependencies
All OHB firmware make use of Arduino Integrated Development Environment.
Board definition
- Open the Arduino IDE
- Navigate to
Preferences - Add
https://movuino.github.io/movuino-board-index/package_movuino_index.jsonas an ‘Additional Board Manager URL’.
Libraries
The following librairies are required to build the firmware and tests:
- MPU9250 by hideakitai : place the version provided in Arduino Librairies
- Adafruit Bluefruit nRF52 : version 0.21.0
- Max86141 : version 1.0.4
Those libraries are all available in the Arduino Library manager except MPU9250 that we should add in Arduino Librairie.
Services and Characteristics for BLE
The following services and characteristics use Notification properties :
Error Service & characteristic
The Error Characteristic allows to send boolean errors from IMU, PPG. Thus, when error is 0 data is detected else 1.
| ErrorService | ErrorCharacteristic | |
|---|---|---|
| UUID | 0x1200 | 0x1201 |
| 2 bytes | byte 1 | byte 2 |
|---|---|---|
| ErrorCharacteristic | errorIMU | errorPPG86 |
IMU Service & characteristic
With the IMU Service and characteristic, data from accelerometer, gyrometer and magnetometer can be send by BLE.
| IMUService | AccGyrMagCharacteristic | |
|---|---|---|
| UUID | 0x1101 | 0x1102 |
| 22 bytes | 4 bytes (0-3) | 2 bytes (4-5) | 2 bytes (6-7) | 2 bytes (8-9) | 2 bytes (10-11) | 2 bytes (12-13) | 2 bytes (14-15) | 2 bytes (16-17) | 2 bytes (18-19) | 2 bytes (20-21) |
|---|---|---|---|---|---|---|---|---|---|---|
| AccGyrMagCharacteristic | timestamp | AccX | AccY | AccZ | GyrX | GyrY | GyrZ | MagX | MagY | MagZ |
PPG Max 86140 - 86141 Service & Characteristics
With the PPG Service and characteristics, data from PPG can be send by BLE. We can have these type of sensor configuartions :
- 1 PD - 2 LEDS
PDLEDs_PD1_SNR1Characteristic = characteristic for data taken from photo-diode
| PPG86Service | PDLEDs_PD1_SNR1Characteristic | |
|---|---|---|
| UUID | 0x1300 | 0x1301 |
| 24 bytes | 4 bytes (0-3) | 4 bytes (4-7) | 4 bytes (8-11) | 4 bytes (12-15) | 4 bytes (16-19) | 4 bytes (20-23) |
|---|---|---|---|---|---|---|
| PDLEDs_PD1_SNR1Characteristic | timestamp | sample 1 | sample 2 | sample 3 | sample 4 | SNR photo-diode |
- 2 PDs - 1 LED
PDsLED_PD1_PD2_SNR1_SNR2Characteristic = characteristic for data taken from photo-diode 1 and 2
| PPG86Service | PDsLED_PD1_PD2_SNR1_SNR2Characteristic | |
|---|---|---|
| UUID | 0x1300 | 0x1302 |
| 28 bytes | 4 bytes (0-3) | 4 bytes (4-7) | 4 bytes (8-11) | 4 bytes (12-15) | 4 bytes (16-19) | 4 bytes (20-23) | 4 bytes (24-27) |
|---|---|---|---|---|---|---|---|
| PDsLED_PD1_PD2_SNR1_SNR2Characteristic | timestamp | sample 1 photo-diode 1 | sample 2 photo-diode 1 | SNR photo-diode 1 | sample 1 photo-diode 2 | sample 2 photo-diode 2 | SNR photo-diode 2 |
- 2 PDs - 3 LEDs
PDsLEDs_PD1_PD2_SNR1_SNR2Characteristic = characteristic for data taken from photo-diode 1 and 2
| PPG86Service | PDsLEDs_PD1_PD2_SNR1_SNR2Characteristic | |
|---|---|---|
| UUID | 0x1300 | 0x1303 |
| 28 bytes | 4 bytes (0-3) | 4 bytes (4-7) | 4 bytes (8-11) | 4 bytes (12-15) | 4 bytes (16-19) | 4 bytes (20-23) | 4 bytes (24-27) |
|---|---|---|---|---|---|---|---|
| PDsLEDs_PD1_PD2_SNR1_SNR2Characteristic | timestamp | sample 1 photo-diode 1 | sample 2 photo-diode 1 | SNR photo-diode 1 | sample 1 photo-diode 2 | sample 2 photo-diode 2 | SNR photo-diode 2 |
HeartRate Service & characteristics
In order to detect the peripheral in the Bluetooth Settings for iPhone, we added the HeartRate taken from Adafruit Bluefruit nrf52 librairies –> Peripheral. However, it is not sent by BLE.
The following service and characteristics use READ and Write properties :
Start_Stop Service & characteristics
With the Start_Stop Service and characteristics, central BLE can decide when to start or stop data transfert and change leds intensity, sample rate and sample average.
| Start_StopService | StartCharacteristic | intensityLedsCharacteristic | smplRateCharacteristic | smplAvgCharacteristic | |
|---|---|---|---|---|---|
| UUID | 0x1400 | 0x1401 | 0x1402 | 0x1403 | 0x1404 |
| 1 byte | 1 byte (0) |
|---|---|
| StartCharacteristic | 1 (start) or 2 (stop) |
| intensityLedsCharacteristic | leds intensity |
| smplRateCharacteristic | PPG sample rate |
| smplAvgCharacteristic | PPG sample average |
| Values | leds intensity |
|---|---|
| 0 - 255 | leds off (min value) - leds on (max value) |
| Values (integer) | PPG sample rate (Hz) |
|---|---|
| 0 | 25 |
| 1 | 50 |
| 2 | 84 |
| 3 | 100 |
| 4 | 200 |
| 5 | 400 |
| 14 | 128 |
| 15 | 256 |
| 16 | 512 |
| Values (integer) | PPG sample average (Hz) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 16 |
| 5 | 32 |
| 6 | 64 |
Use
- Choose your PPG sensor type (PDLEDs, PDsLED or PDsLEDs) by activating the #define
- To read data from PPG, IMU activated the #define from peripheral and central
- To read data on Serial Monitor or send by BLE activate the #define from peripheral
Documentation
Documentation for the project is available at movuino.github.io/OpenHealthBandFirmware or in the /docs folder.
Integration
OHB firmware can integrate with the Open Health Band Visualization project which provide real time monitoring of the OHB sensors in a web browser.