Analog Devices Inc./Maxim Integrated 的 MAXREFDES117# 规格书

maxim Integrated m um WIN mourn/MILD mum ® Mm many so. Sm
System Board 6300
MAXREFDES117#: Heart-Rate and Pulse-Oximetry Monitor
The MAXREFDES117# reference design is a low power, optical heart-rate module
complete with integrated red and IR LEDs, and a power supply. This tiny board, perfect
for wearable projects, may be placed on a finger or earlobe to accurately detect heart
rate. This versatile module works with both Arduino and mbed platforms for quick
testing, development and system integration. A basic, open-source heart-rate and SpO
2
algorithm is included in the example firmware.
The board features 8 sewing tap pads for attachment and quick electrical connection to
a development platform.
MAXREFDES117# System Board MAXREFDES117# Reference Design Block Diagram
Features
Optical Heart-Rate Monitor and Pulse Oximetry Solution
Tiny 12.7mm x 12.7mm (0.5in x 0.5in) Board Size
Low Power
Device Drivers
Free Algorithm
Example C Source Code For Arduino And mbed Platforms
Test Data
Competitive Advantages
Highly-integrated, small-size sensor
Non-chest based heart-rate/SpO2 detection
Ultra-low power consumption
em Diagram ® MAX‘I4595 LEVEL TRANSLATOR ARDUINO/M BED PLATFORM ® MAxamuz HEARFRATE/ SPO: SENSOR 15v ® MAX192| STEP-DOWN UDNVEKTER
Applications
Wearables
Heart-rate monitor
Pulse oximeter
Introduction
Wearable devices hold the potential to transform health and medical monitoring. Heart
rate, specifically, provides tremendous insight into heart function and health, during
both activity and rest. Innovation and development of both optical semiconductors and
lower-power integrated circuits makes the transition to wearables possible. Until now,
only large organizations, with deep development budgets, could deliver such advanced
products.
MAXREFDES117# delivers the promise of wearable devices to all developers. This
unique design measures both heart rate and pulse oximetry. MAXREFDES117#
features the MAX30102 with integrated red and IR LEDs for heart-rate and SpO2
detection. This configuration ideally detects heart rate and pulse ox on a person’s
fingertip, earlobe, or other fleshy extremity. The small board size of 12.7mm x 12.7mm
(0.5in x 0.5in) is ideal for wearable applications and may be stitched into fabric for
immediate prototyping. Firmware is available for both Arduino and mbed platforms,
enabling users to develop with virtually any platform. User needs to provide a 2V to
5.5V supply at the power input, perfect for virtually any battery or Arduino and mbed
form-factor board.
The MAXREFDES117# design utilizes the heart-rate/SpO
2
sensor (MAX30102), an
efficient, low-power step-down converter (MAX1921), and an accurate level translator
(MAX14595). The entire design typically operates at less than 5.5mW when using with
the example firmware. A block diagram of the system is shown in Figure 1.
System Diagram
Figure 1. MAXREFDES98# reference design block diagram.
The power requirement is shown in Table 1.
Table 1. Power Requirement for the MAXREFDES117# Reference Design
Input Voltage (V) 2V to 5.5V
Input Current (mA, typ) 1.5mA (3.3V input)
Note: Controller board is powered separately
The MAXREFDES117# reference design is a PPG-based heart-rate and SpO2 monitor
subsystem. The circuit utilizes the MAX30102 heart-rate/SpO2 sensor with integrated
red and IR LEDs. The step-down converter MAX1921 converts the 2V to 5.5V supply
input and generates the 1.8V rail for the heart-rate sensor. The MAX14595 level
translator provides an interface between the heart-rate/SpO2 sensor and the controller
board, which generally use a different logic level.
Detailed Description of Firmware
The MAXREFDES117# can be used with virtually any microcontroller that has I2C
interface. The Arduino and mbed example firmware have been tested on the following
development platforms:
mbed:
Maxim Integrated MAX32600MBED#
Freescale FRDM-K64F
Freescale FRDM-KL25Z
Arduino:
Adafruit Flora
Lilypad USB
Arduino UNO
Users may read sampled data, calculated heart rate and SpO
2
through a terminal
program, allowing analysis on excel or any third-party software. The simple process
flow is shown in Figure 2.
sun COLLECT ‘ szcouo or mu AND CASCADE Y0 THE PREVIousLV sAMPLw BLOCK or mu puss A KEY To sum SAMPLING mmALIzE MAXW‘OZ sEnINGs nwovz m: FIRSY SECOND or DATA mm In: sum, Jr coma 3 secon or DAYA roux Amuwo. on comm 5 sscouns or DATA FOR MEED —l nunsmr "m2 mu 10 pc RUN run/3P0: ALGORIYNM
Figure 2. The MAXREFDES117# firmware flowchart.
Figure 2. The MAXREFDES117# firmware flowchart.
The complete source code, including the heart rateheart-rate/SpO
2
algorithm, is
provided to accelerate development. Code documentation can be found in the
corresponding firmware platform files.
Heart rateHeart-rate accuracy varies depending on the chosen platform. The tested
mbed platforms give more accurate heart-rate/SpO2 calculations than the tested
Arduino platforms because the mbed platform controllers have more SRAM than the
Arduino platform controllers. For the example firmware, mbed platforms store 5
seconds of samples collected at 100sps, while the Arduino platforms store 4 seconds of
samples collected at 25sps.
SpO
2
calculation is based on the equation shown below. However, determining the
constants (C1, C2, and C3) requires a comprehensive clinical study of pulse pulse-
oximetry data from a statistically significant population set using this hardware. Such a
clinical study is beyond scope of this design. Therefore, the calculated SpO2 value may
havecan have an error.
SpO
2
= C
1
× AverageRatio
2
+ C
2
× AverageRation + C
3
Where AverageRatio is the average ratio of IR and red LED readings. C
1
, C
2
, and C
3
are constants.
AM
Quick Start
Required equipment:
• Windows PC with a USB port
• MAXREFDES117# board
• 5 cables that can be used to connect the MAXREFDES117# with the controller board
• One of the supported mbed or Arduino controller boards listed above
• One USB cable that is compatible with the selected controller board
Download, read, and carefully follow each step in the appropriate MAXREFDES117# quick
Start Guide:
MAXREFDES117# mbed Quick Start Guide
Quick Start
Required equipment:
• Windows PC with a USB port
• MAXREFDES117# board
• 5 cables with grabber clips on both ends.
• One of the three supported controller boards (Adafruit Flora, Lilypad USB, or Arduino
UNO board)
• One micro USB cable (for Lilipad or Flora)
• One A to B USB cable (for Arduino UNO) Procedure
The reference design is fully assembled and tested. Follow the steps below to verify board
operation:
1. If Arduino IDE is not installed on the PC follow the getting started guide to install the
Arduino IDE on the PC.
2. If Adafruit Flora board is selected as the controller board:
◦Follow the Adafruit Windows Driver installation guide to install the driver.
◦Follow the "Adafruit Arduino IDE setup guide" to install the Arduino IDE and
support files for Adafruit Flora board.
3. Download the source code RD117_ARDUINO.zip file and unzip it in a desired
location.
4. Double click the RD117_ARDUINO.ino to open the project in Arduino IDE.
5. Connect the MAXREFDES117 to the controller board: For Flora
Flora port MAXREFDES117 port
SDA SDA
SCL SCL
D10 INT
3.3V VIN
GND GND
For Lilypad USB
Lilypad USB port MAXREFDES117 port
2SDA
3SCL
10 VIN
+VIN
-GND
For Arduino UNO
Arduino UNO port MAXREFDES117 port
SDA SDA
SCL SCL
10 INT
3.3V VIN
GND GND
6. Connect the controller board to the PC with a USB cable.
7. In the Arduino IDE, click on the Tools menu and make sure the appropriate board is
selected.
8. Select the proper communication port in the Tools menu.
9. Press the Upload menu item in the Sketch menu to upload the firmware to the Flora
board.
AM u—noou. k-ussu. mucus. n-nuoi. k-“fl”. unuwu. nun-111:. ”-11.7911. u-uuoo. u-uulo. mum. u-anzu. n—unu. u-‘ulm. 2-: u. u-uuszl. n—unna. manna-1 smug-a. mt: mmwx
10. Open Hyperterminal or a similar terminal program on the PC. Find the appropriate
COM port and configure the connection for 115200, 8-N-1 with no flow control.
11. Put a finger on top of the U1 on the MAXREFDES117#, contact with an earlobe is
also sufficient. Constant pressure yields the best result.
12. Press any key on the terminal program and the system will start the conversion.
13. From left to right, the first two column shows the data for red and IR LED receiver.
Third and fifth columns show the calculated heart rate and SpO2 values. And the
fourth and sixth columns show the validities of the heart rate and SpO2 calculations.
MAXREFDES117# Arduino Quick Start Guide
Quick Start: Required equipment:
• Windows PC with a USB port
• MAXREFDES117# board
• 5 pieces of wires to connect the MAXREFDES117# to the controller board
• One of the three supported controller boards (Maxim Integrated MAX32600MBED#,
Freescale FRDM-KL25Z, or Freescale FRDM-K64F)
• One micro USB cable (for MAX32600MBED# and FRDM-K64F)
• One mini USB cable (for FRDM-KL25Z) Procedure
The reference design is fully assembled and tested. Follow the steps below to verify board
operation:
1. Create an account on http://developer.mbed.org to use their online compiler.
2. Import the demo program from https://developer.mbed.org/teams/Maxim-
Integrated/code/RD117_MBED/
3. Connect the MAXREFDES117 to the controller board: For MAX32600MBED#
MAX32600MBED# port MAXREFDES117 port
P26 SDL SDA
P27 SCL SCL
P20 SCK RX INT
3.3V VIN
GND GND
For FRDM-K64F
FRDM-K64F port MAXREFDES117 port
E25 SDA
E24 SCL
D1 INT
P3V3 VIN
GND GND
For FRDM-KL25Z
FRDM-KL25Z port MAXREFDES117 port
E0 SDA
E1 SCL
D1 INT
3.3V VIN
GND GND
4. Connect the controller board to the PC with a USB cable.
5. In the MBED compiler, click the button at the upper right hand corner to select the
appropriate controller board.
6. Compile and download the resulting binary to your mbed platform.
7. Press the Upload menu item in the Sketch menu to upload the firmware to the Flora
board.
HEART EAT (BEATS/MIN) 180 160 140 120 3 § :- :3 MAXREFDES'I‘W” VS CHEST STRAP — MAXREFDESHN — POLAR H7 200 400 600 800 TIME (S) W 1000 1200
8. Open Hyperterminal or a similar terminal program on the PC. Find the appropriate
COM port and configure the connection for 115200, 8-N-1 with no flow control.
9. Put a finger on top of the U1 on the MAXREFDES117#, contact with an earlobe is
also sufficient. Constant pressure yields the best result.
10. Press any key on the terminal program and the system will start the conversion.
11. From left to right, the first two column shows the data for red and IR LED receiver.
Third and fifth columns show the calculated heart rate and SpO2 values. And the
fourth and sixth columns show the validities of the heart rate and SpO2 calculations.
Lab Measurements
Equipment used:
• MAX32600MBED#
• Adafruit Flora
• Adafruit BlueFruit
• Polar H7 Bluetooth Smart Heart RateHeart-Rate Sensor
• Android tablet
Figure 3 and Figure 4 show how the MAXREFDES117 calculated heart rate compared to
the Polar H7 chest strap. The data in Figure 3 were taken while the person was sitting still
for 20 minutes. And the data in Figure 4 were taken while the person was walking at a
normal speed for 20 minutes.
Figure 3. For sedentary test, over 99% of the mbed + MAXREFDES117# heart heart-rate
data are less than 5 beats/min delta from the Polar H7 chest strap.
MAXREFDESTIWI VS POLAR H7 — MAXREF DESI17# —POLAR H7 =fia'. coo HEART BEAT (HEATS/MIN) 8 8 8 u 3 0 200 400 600 800 1000 1200 TIME (5) ated.com/en/design/reference n mb 8/ /
Figure 4. For moving test, over 92% of the Arduino + MAXREFDES117# heart- rate data
are less than 10 beats/min delta from the Polar H7 chest strap.
8
/
17
/
201
6
https://www.maximintegrated.com/en/design/referenc
e
-desig
n
-center/syste
m
-
b
oard/6300.
h
...