Heartrate Example

examples/ex5_HeartRate.py
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
#!/usr/bin/env python
#-----------------------------------------------------------------------------
# ex5_HeartRate.py
#
# Simple example for the qwiic MAX3010x device
# This is a demo to show the reading of heart rate or beats per minute (BPM) using
# a Penpheral Beat Amplitude (PBA) algorithm.
#
# It is best to attach the sensor to your finger using a rubber band or other tightening
# device. Humans are generally bad at applying constant pressure to a thing. When you
# press your finger against the sensor it varies enough to cause the blood in your
# finger to flow differently which causes the sensor readings to go wonky.
#
#------------------------------------------------------------------------
#
# Written by Pete Lewis
# SparkFun Electronics, May 2020
#
# Based on code from the SparkFun MAX3010x Sensor Arduino Library
# https://github.com/sparkfun/SparkFun_MAX3010x_Sensor_Library
# By: Nathan Seidle @ SparkFun Electronics, October 2nd, 2016
# 
# This python library supports the SparkFun Electroncis qwiic 
# qwiic sensor/board ecosystem on a Raspberry Pi (and compatable) single
# board computers. 
#
# More information on qwiic is at https://www.sparkfun.com/qwiic
#
# Do you like this library? Help support SparkFun. Buy a board!
#
#==================================================================================
# Copyright (c) 2019 SparkFun Electronics
#
# 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 THE 
# AUTHORS OR COPYRIGHT HOLDERS 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.
#==================================================================================
# Example 5
#

from __future__ import print_function
import qwiic_max3010x
import time
import sys

def millis():
	return int(round(time.time() * 1000))

def runExample():

	print("\nSparkFun MAX3010x Photodetector - Example 5\n")
	sensor = qwiic_max3010x.QwiicMax3010x()

	if sensor.begin() == False:
		print("The Qwiic MAX3010x device isn't connected to the system. Please check your connection", \
			file=sys.stderr)
		return
	else:
		print("The Qwiic MAX3010x is connected.")

	print("Place your index finger on the sensor with steady pressure.")

	if sensor.setup() == False:
		print("Device setup failure. Please check your connection", \
			file=sys.stderr)
		return
	else:
		print("Setup complete.")

	sensor.setPulseAmplitudeRed(0x0A) # Turn Red LED to low to indicate sensor is running
	sensor.setPulseAmplitudeGreen(0) # Turn off Green LED

	RATE_SIZE = 4 # Increase this for more averaging. 4 is good.
	rates = list(range(RATE_SIZE)) # list of heart rates
	rateSpot = 0
	lastBeat = 0 # Time at which the last beat occurred
	beatsPerMinute = 0.00
	beatAvg = 0
	samplesTaken = 0 # Counter for calculating the Hz or read rate
	startTime = millis() # Used to calculate measurement rate
	
	while True:
                
		irValue = sensor.getIR()
		samplesTaken += 1
		if sensor.checkForBeat(irValue) == True:
			# We sensed a beat!
			print('BEAT')
			delta = ( millis() - lastBeat )
			lastBeat = millis()	
	
			beatsPerMinute = 60 / (delta / 1000.0)
			beatsPerMinute = round(beatsPerMinute,1)
	
			if beatsPerMinute < 255 and beatsPerMinute > 20:
				rateSpot += 1
				rateSpot %= RATE_SIZE # Wrap variable
				rates[rateSpot] = beatsPerMinute # Store this reading in the array

				# Take average of readings
				beatAvg = 0
				for x in range(0, RATE_SIZE):
					beatAvg += rates[x]
				beatAvg /= RATE_SIZE
				beatAvg = round(beatAvg)
        
		Hz = round(float(samplesTaken) / ( ( millis() - startTime ) / 1000.0 ) , 2)
		if (samplesTaken % 200 ) == 0:
                        
			print(\
				'IR=', irValue , ' \t',\
            				'BPM=', beatsPerMinute , '\t',\
                                                                                #'DCE', getDCE() , '\t',\
            				'Avg=', beatAvg , '\t',\
				'Hz=', Hz, \
				)

if __name__ == '__main__':
	try:
		runExample()
	except (KeyboardInterrupt, SystemExit) as exErr:
		print("\nEnding Example 5")
		sys.exit(0)