/ \file RD117_LILYPAD.ino ************

• Project: MAXREFDES117#
• Filename: RD117_LILYPAD.ino
• Description: This module contains the Main application for the MAXREFDES117 example program.
• Revision History:
• \n 1-18-2016 Rev 01.00 GL Initial release.
• \n
• --------------
• This code follows the following naming conventions:
• char ch_pmod_value
• char (array) s_pmod_s_string[16]
• float f_pmod_value
• int32_t n_pmod_value
• int32_t (array) an_pmod_value[16]
• int16_t w_pmod_value
• int16_t (array) aw_pmod_value[16]
• uint16_t uw_pmod_value
• uint16_t (array) auw_pmod_value[16]
• uint8_t uch_pmod_value
• uint8_t (array) auch_pmod_buffer[16]
• uint32_t un_pmod_value
• int32_t * pn_pmod_value
• --------------- */ /*****************
• Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
• Permission is hereby granted, free of charge, to any person obtaining a
• copy of this software and associated documentation files (the "Software"),
• to deal in the Software without restriction, including without limitation
• the rights to use, copy, modify, merge, publish, distribute, sublicense,
• and/or sell copies of the Software, and to permit persons to whom the
• Software is furnished to do so, subject to the following conditions:
• The above copyright notice and this permission notice shall be included
• in all copies or substantial portions of the Software.
• THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
• OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
• MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
• IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
• OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
• ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
• OTHER DEALINGS IN THE SOFTWARE.
• Except as contained in this notice, the name of Maxim Integrated
• Products, Inc. shall not be used except as stated in the Maxim Integrated
• Products, Inc. Branding Policy.
• The mere transfer of this software does not imply any licenses
• of trade secrets, proprietary technology, copyrights, patents,
• trademarks, maskwork rights, or any other form of intellectual
• property whatsoever. Maxim Integrated Products, Inc. retains all
• ownership rights.
• / /*!\mainpage Main Page
• \section intro_sec Introduction
• This is the code documentation for the MAXREFDES117# subsystem reference design.
• The Files page contains the File List page and the Globals page.
• The Globals page contains the Functions, Variables, and Macros sub-pages.
• \image html MAXREFDES117_Block_Diagram.png "MAXREFDES117# System Block Diagram"
• \image html MAXREFDES117_firmware_Flowchart.png "MAXREFDES117# Firmware Flowchart"
• /

1. include <Arduino.h>
2. include "algorithm.h"
3. include "max30102.h"

if Adafruit Flora development board is chosen, include NeoPixel library and define an NeoPixel object

1. if defined(ARDUINO_AVR_FLORA8)
2. include "adafruit_neopixel.h"
3. define BRIGHTNESS_DIVISOR 8 to lower the max brightness of the neopixel LED Adafruit_NeoPixel LED = Adafruit_NeoPixel(1, 8, NEO_GRB + NEO_KHZ800);
4. endif

1. define MAX_BRIGHTNESS 255

1. if defined(ARDUINO_AVR_UNO) Arduino Uno doesn't have enough SRAM to store 100 samples of IR led data and red led data in 32-bit format To solve this problem, 16-bit MSB of the sampled data will be truncated. Samples become 16-bit data. uint16_t aun_ir_buffer[100]; infrared LED sensor data uint16_t aun_red_buffer[100]; red LED sensor data
2. else uint32_t aun_ir_buffer[100]; infrared LED sensor data uint32_t aun_red_buffer[100]; red LED sensor data
3. endif int32_t n_ir_buffer_length; data length int32_t n_spo2; SPO2 value int8_t ch_spo2_valid; indicator to show if the SPO2 calculation is valid int32_t n_heart_rate; heart rate value int8_t ch_hr_valid; indicator to show if the heart rate calculation is valid uint8_t uch_dummy;

the setup routine runs once when you press reset: void setup() {

1. if defined(ARDUINO_AVR_LILYPAD_USB) pinMode(13, OUTPUT); LED output pin on Lilypad
2. endif

1. if defined(ARDUINO_AVR_FLORA8) Initialize the LED LED.begin(); LED.show();
2. endif

maxim_max30102_reset(); resets the MAX30102 initialize serial communication at 115200 bits per second: Serial.begin(115200); pinMode(10, INPUT); pin D10 connects to the interrupt output pin of the MAX30102 delay(1000); maxim_max30102_read_reg(REG_INTR_STATUS_1,&uch_dummy); Reads/clears the interrupt status register while(Serial.available()==0) wait until user presses a key { Serial.write(27); ESC command Serial.print(F("[2J")); clear screen command

1. if defined(ARDUINO_AVR_LILYPAD_USB) Serial.println(F("Lilypad"));
2. endif
3. if defined(ARDUINO_AVR_FLORA8) Serial.println(F("Adafruit Flora"));
4. endif Serial.println(F("Press any key to start conversion")); delay(1000); } uch_dummy=Serial.read(); maxim_max30102_init(); initialize the MAX30102 }

the loop routine runs over and over again forever: void loop() { uint32_t un_min, un_max, un_prev_data, un_brightness; variables to calculate the on-board LED brightness that reflects the heartbeats int32_t i; float f_temp;

un_brightness=0; un_min=0x3FFFF; un_max=0;

n_ir_buffer_length=100; buffer length of 100 stores 4 seconds of samples running at 25sps

read the first 100 samples, and determine the signal range for(i=0;i<n_ir_buffer_length;i++) { while(digitalRead(10)==1); wait until the interrupt pin asserts maxim_max30102_read_fifo((aun_red_buffer+i), (aun_ir_buffer+i)); read from MAX30102 FIFO

if(un_min>aun_red_buffer[i]) un_min=aun_red_buffer[i]; update signal min if(un_max<aun_red_buffer[i]) un_max=aun_red_buffer[i]; update signal max Serial.print(F("red=")); Serial.print(aun_red_buffer[i], DEC); Serial.print(F(", ir=")); Serial.println(aun_ir_buffer[i], DEC); } un_prev_data=aun_red_buffer[i]; calculate heart rate and SpO2 after first 100 samples (first 4 seconds of samples) maxim_heart_rate_and_oxygen_saturation(aun_ir_buffer, n_ir_buffer_length, aun_red_buffer, &n_spo2, &ch_spo2_valid, &n_heart_rate, &ch_hr_valid);

Continuously taking samples from MAX30102. Heart rate and SpO2 are calculated every 1 second while(1) { i=0; un_min=0x3FFFF; un_max=0;

dumping the first 25 sets of samples in the memory and shift the last 75 sets of samples to the top for(i=25;i<100;i++) { aun_red_buffer[i-25]=aun_red_buffer[i]; aun_ir_buffer[i-25]=aun_ir_buffer[i];

update the signal min and max if(un_min>aun_red_buffer[i]) un_min=aun_red_buffer[i]; if(un_max<aun_red_buffer[i]) un_max=aun_red_buffer[i]; }

take 25 sets of samples before calculating the heart rate. for(i=75;i<100;i++) { un_prev_data=aun_red_buffer[i-1]; while(digitalRead(10)==1); digitalWrite(9, !digitalRead(9)); maxim_max30102_read_fifo((aun_red_buffer+i), (aun_ir_buffer+i));

calculate the brightness of the LED if(aun_red_buffer[i]>un_prev_data) { f_temp=aun_red_buffer[i]-un_prev_data; f_temp/=(un_max-un_min); f_temp*=MAX_BRIGHTNESS; f_temp=un_brightness-f_temp; if(f_temp<0) un_brightness=0; else un_brightness=(int)f_temp; } else { f_temp=un_prev_data-aun_red_buffer[i]; f_temp/=(un_max-un_min); f_temp*=MAX_BRIGHTNESS; un_brightness+=(int)f_temp; if(un_brightness>MAX_BRIGHTNESS) un_brightness=MAX_BRIGHTNESS; }

1. if defined(ARDUINO_AVR_LILYPAD_USB) analogWrite(13, un_brightness);
2. endif

1. if defined(ARDUINO_AVR_FLORA8) LED.setPixelColor(0, un_brightness/BRIGHTNESS_DIVISOR, 0, 0); LED.show();
2. endif

send samples and calculation result to terminal program through UART Serial.print(F("red=")); Serial.print(aun_red_buffer[i], DEC); Serial.print(F(", ir=")); Serial.print(aun_ir_buffer[i], DEC);

Serial.print(F(", HR=")); Serial.print(n_heart_rate, DEC);

Serial.print(F(", HRvalid=")); Serial.print(ch_hr_valid, DEC);

Serial.print(F(", SPO2=")); Serial.print(n_spo2, DEC);

Serial.print(F(", SPO2Valid=")); Serial.println(ch_spo2_valid, DEC); } maxim_heart_rate_and_oxygen_saturation(aun_ir_buffer, n_ir_buffer_length, aun_red_buffer, &n_spo2, &ch_spo2_valid, &n_heart_rate, &ch_hr_valid); } }