Question

The OP has setup and successfully detected an I2C MAX30100 Pulse Oximeter and Heart-Rate Sensor module. But when trying to read the sensor, he encounters two problems:

(1) Gets the "Exception remote I/O error [error 121]",

(2) Gets only zero values for the red LED and IR Led outputs.

How to fix it?

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Answer

Part A – Setting up and preliminary testing

(1) Suggest to check I2C wiring and use “i2cdetect” and “i2cget” to find max30100 chip at I2C Bus #1, I2C device address 0x57, and Part ID 0x11 or 0x15 at max30100 register address 0xFF, as show below. (Note: MAX30100 Part ID is 0x11, MAX30102 is 0x15)

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(2) The OP’s Test Results

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(3) Using max30100’s library methods to read PartID register OK.

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Part B – Pulse Oximeter and Heart Rate Measurements

(1) Hardware Setup

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(2) The simplest read sensor program

(3) Minimal program to read registers and sensor

Sample Output

partID = 0x15

revID = 0x3

temperature = 14.9375

ir = 3 red = 1

ir = 3 red = 1

ir = 3 red = 1

ir = 3 red = 1

# max30100test12.py tlfong01 2020may08hkt1941
# Rpi4B buster (2020feb13), linux 4.19.97
# python 3.7.3 (2019dec20) thonny v3.2.7 (2020jan22)

import max30100lib07 as max30100

# *** Test Function ***

sensor1 = max30100.MAX30100()

def setupSensor(sensor):
    sensor.reinit()
    sensor.set_mode(max30100.MODE_SPO2)
    return

def resetSensor(sensor):
    sensor.reset()
    return

def readRegisters(sensor):    
    # *** Read PartId ***
    partId =  sensor.get_part_id()
    print('partID      =', hex(partId))

     # *** Read Rev Id ***
    revId =  sensor.get_rev_id()
    print('revID       =', hex(revId))   

    # *** Read Temperature ***
    temperature =  sensor.get_temperature()
    print('temperature =', temperature)    

    return

def readSensor(sensor):
    totalCount = 4
    for count in range(totalCount):
        sensor.read_sensor()
        print('ir          =', sensor.ir, '          red           =', sensor.red)
    return

# *** Main ***

setupSensor(sensor1)
readRegisters(sensor1)
readSensor(sensor1)
resetSensor(sensor1)

# *** End of program ***

# *** Sample output  tlfong01  2020may08hkt2135 ***
'''
>>> %Run max30100test12.py
partID      = 0x15
revID       = 0x3
temperature = 14.9375
ir          = 3           red           = 1
ir          = 3           red           = 1
ir          = 3           red           = 1
ir          = 3           red           = 1
>>> 
'''

* End of Sample output *

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References

(1) MAX30100 Pulse Oximeter and Heart-Rate Sensor IC for Wearable Health Datasheet – Maxim

(2) MAX30102 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health – Maxim

(3) whilemind/MAX30100u max30100 Library

(4) whilemind/MAX30100u max30100 Class (max30100.py)

(5) whilemind/MAX30100u max30100 Test (test_max30100.py)

(6) mfitzp/max30100 max30100 Library

(7) kontakt/max30100 Library

(8) Amazon MAX30100 Pulse Oximeter Heart Rate Sensor Module – Lysignal

(9) AliEXpress GY-MAX30100 Pulse Oximeter Heart Rate Sensor Module – US$7

(10) TaoBao Risym GY-MAX30100 MAX30102 Pulse Oximeter Heart Rate Sensor Module – ￥35

(11) Amazon MAX30102 Pulse Oximeter Heart Rate Sensor Module

(12) Pulse Oximeter Instructable – MolecularD 2019sep

(13) max30100/102 pulse sensor discussion – ParticleCommunity

(11) TaoBao GY-MAX30100 MAX30102 Pulse Oximeter and Heart-Rate Sensor – ￥35

(12) Pulse Oximeter Instructable – MolecularD 2019sep

(13) Amazon max30102 Pulse Oximeter and Heart-Rate Sensor

(14) Particle.Community max30100 Forum Discussion

(15) Implementing pulse oximeter using MAX30100 Blog – Raivis Strogonovs 2017

(16) Max30100 Heart Rate Monitor Youtube Video – Maxim

(17) AD8232 ECG / Haeart Rate Sensor Rpi.StackExchange Forum Discusson

(18) Oxygen Saturation – Wikipedia

(19) Pull-up Resistors Tutorial – Electronics.Tutorials

(20) Application note AN10441 Level shifting techniques in I2C-bus design R0.1 2007jun18 – NXP

(21) I2C Bus Pullup Resistor Calculation, Application Report SLVA689, TI 2015feb

(22) Setting up multiple I2C buses using dtoverlay [Rpi4B] – rpi.stackexchange forum post 2019sep30

(23) What is Rpi4B I2C Maximum Speed?

(24) A Guide to Voltage Translation With TXS-Type Translators – TI

(25) MAX30100/02 Oximeter – How to fix wrong board – Valeriy Yatsenkov 2018aug22

(26) SC6206B LDO 65K5 (1V5 to 5V0, 250 mA) Datasheet – LCSC

(27) Max30100 pulse Oximeter Arduino Code, circuit, and Programming – Engr Fahad, Electronic Clinic 2020feb23

(28) How pulse oximeters work explained simply – Howeauipmentworks

(29) MAX30100 Pulse Oxmeter and Heart Rate Sensor (Arduino 5V input, use external 4k7 pullup to 5V, instead of 1V8)

(30) MAX30105 Particle and Pulse Oxmeter (Vin 5V, green LED won’t work if Vin is 3V3)

(31) Bash V5.0 User Manual – 2019may

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Appendices

*Appendix A – MAX30100 *

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Figures

Fig 1 – MAX3010x System Diagram

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Fig 2 – MAX3010x Function Diagram

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Fig 3 – MAX3010x Register Map Summary

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Fig 4 – GY-MAX30102 Module Schematic

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Fig 5 – GY-MAX00 ProductSheet

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Fig 6 – GY-MAX30100 PCB Components Layout Diagram

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Fig 7 – Rpi4B to MAX30100 Module Wiring Diagram

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Fig 8 – MAX30102 PCB and Components Layout

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Program Listings

(1) read_max30100.py tlfong01 2020may05hkt1936

# read_max30100.py tlfong01 2020may05hkt1936
# Rpi4B buster (release 2020feb13, linux 4.19.97), thonny v3.2.7 (release 2020jan22)
# Reference: https://github.com/whilemind/MAX30100u/blob/master/test_max30100.py

import max30100

# import max30100lib07 as max30100

# *** Test Functions ***

def readMax30100PartIdRegister():

    sensor = max30100.MAX30100()
    sensor.reinit()
    sensor.set_mode(max30100.MODE_SPO2)

    partIdRegisterContents =  sensor.get_part_id()

    # partIdRegisterContents = 'fakeFakeFake'

    print('max30100 Part ID register contents =', partIdRegisterContents)

    sensor.reset()

    return

# *** Main ***

readMax30100PartIdRegister()

# End of program

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(2) Setting up multiple I2C buses

# fi2c62.py  tlfong01 2019aug28hkt1433

from time          import sleep
import             smbus
import             fprint53    as fprint
import             ftime53     as ftime

# I2c Bus Setup Notes
# pi@raspberrypi:~ $ date Wed 28 Aug 2019 03:26:24 PM HKT
# pi@raspberrypi:~ $ uname -a
# Linux raspberrypi 4.19.58-v7l+ #1245 SMP Fri Jul 12 17:31:45 BST 2019 armv7l GNU/Linux
# pi@raspberrypi:~ $ sudo nano /boot/config.txt
# dtoverlay=i2c1,pins_2_3  (board pins 3, 5)
# dtoverlay=i2c3,pins_4_5  (board pins 7, 29)
# dtoverlay=i2c4,pins_6_7  (board pins 31, 26)
# dtoverlay=i2c5,pins_12_13 (board pins 32, 33)
# dtoverlay=i2c6,pins_22_23 (board pins 15, 16)
# pi@raspberrypi:~ $ ls /dev/i2c*
# /dev/i2c-1  /dev/i2c-3  /dev/i2c-4  /dev/i2c-5  /dev/i2c-6

# ********************************************************************************
# ********************************************************************************

# *** I2c Bus Config ***

i2cBus1 = smbus.SMBus(1) 
i2cBus3 = smbus.SMBus(3)
i2cBus4 = smbus.SMBus(4)
i2cBus5 = smbus.SMBus(5)

i2cBusDict = {'I2cBus1': i2cBus1,
              'I2cBus3': i2cBus3,
              'I2cBus4': i2cBus4,
              'I2cBus5': i2cBus5,
             }

# *** Pca9685 I2c Slave Device Congif ***

pca9685DevAddrDict = {
                'Dev0': 0x40,
                'Dev1': 0x41,
                'Dev2': 0x42,
                'Dev3': 0x43,
                'Dev4': 0x44,
                'Dev5': 0x45,
                'Dev6': 0x46,
                'Dev7': 0x47,
              }

pca9685RegAddrDict = { 'Mode1': 0x00,
                       'Mode2': 0x01,
                     }

pca9685DataByteDict = {
                       'Mode1Reset': 0x11,

    }

# ********************************************************************************
# ********************************************************************************

# *** Read Write Print Device/Register Functions ***

def writeDevTwoBytes(i2cBus, devAddr, writeByte1, writeByte2):
    i2cBus.write_byte_data(devAddr, writeByte1, writeByte2)
    return

def writeRegOneByte(i2cBus, devAddrDict, devName, regAddrDict, regName, writeByte):
    devAddr = devAddrDict[devName]
    regAddr = regAddrDict[regName]
    writeDevTwoBytes(i2cBus, devAddr, regAddr, writeByte)
    return

def readDevOneByte(i2cBus, devAddr, readByteAddr):
    readByte = i2cBus.read_byte_data(devAddr, readByteAddr)
    return readByte

def readRegOneByte(i2cBus, devAddrDict, devName, regAddrDict, regName):
    devAddr = devAddrDict[devName]
    regAddr = regAddrDict[regName]
    readByte = i2cBus.read_byte_data(devAddr, regAddr)
    return readByte

def printRegOneByte(i2cBus, devAddrDict, devName, regAddrDict, regName):
    readByte = readRegOneByte(i2cBusName, devAddrDict, devName, regAddrDict, regName)
    print(printTitle, hex(readByte))
    return

# *** Main Test Function ***

def testWriteReadPca9685Bus1Dev0RegMode1():     
    fprint.printBeginExecFunction()

    i2cBusName = 'I2cBus1'
    devName    = 'Dev0'
    regName    = 'Mode1'

    #i2cBus      = fi2c.i2cBusDict[i2cBusName]
    i2cBus      = i2cBusDict[i2cBusName]
    devAddrDict = pca9685DevAddrDict
    regAddrDict = pca9685RegAddrDict  

    writeByte = 0x77

    writeRegOneByte(i2cBus, devAddrDict, devName, regAddrDict, regName, writeByte)
    readByte = readRegOneByte(i2cBus, devAddrDict, devName, regAddrDict, regName) 

    if readByte == writeByte:
        resultsString = 'Good'
    else:
        resultsString = 'Bad'

    devAddr = devAddrDict[devName]

    fprint.printTitleOneByteNum('PCA9685 I2C Address',             fprint.indentFormat640, devAddr)
    fprint.printTitleOneByteNum('PCA9685 MODE1 Register Written',  fprint.indentFormat640, writeByte) 
    fprint.printTitleOneByteNum('PCA9685 MODE1 Register Read',     fprint.indentFormat640, readByte)    
    fprint.printTitleString('Write/Read Results',                  fprint.indentFormat640, resultsString)

    fprint.printEndExecFunction()
    return

def testPingPca9685Bus1Dev0RegMode1():     
    fprint.printBeginExecFunction()

    i2cBusName = 'I2cBus1'
    devName    = 'Dev0'
    regName    = 'Mode1'

    #i2cBus      = fi2c.i2cBusDict[i2cBusName]
    i2cBus      = i2cBusDict[i2cBusName]
    devAddrDict = pca9685DevAddrDict
    regAddrDict = pca9685RegAddrDict

    devAddr = devAddrDict[devName]

    readByte = readRegOneByte(i2cBus, devAddrDict, devName, regAddrDict, regName)    

    compareByte = pca9685DataByteDict['Mode1Reset'] 

    if readByte == compareByte:
        resultsString = 'Good'
    else:
        resultsString = 'Bad'

    fprint.printTitleString('PCA9685 I2C Address',             fprint.indentFormat640, hex(devAddr))
    fprint.printTitleString('PCA9685 MODE1 Register Written',  fprint.indentFormat640, hex(compareByte)) 
    fprint.printTitleString('PCA9685 MODE1 Register Read',     fprint.indentFormat640, hex(readByte))    
    fprint.printTitleString('Ping Results',                    fprint.indentFormat640, resultsString)

    fprint.printEndExecFunction()
    return

# ********************************************************************************
# ********************************************************************************

# *** Main Tests ***

def mainTests():
    #ftime.testPrintDateTime()
    testPingPca9685Bus1Dev0RegMode1()
    testWriteReadPca9685Bus1Dev0RegMode1()
    return

# ********************************************************************************
# ********************************************************************************

# *** Init/Main Functions ***

# *** Init Function ***

def init():
    pass
    return

#*** Main Function ***

def main():
    init()
    mainTests()    
    return

# ********************************************************************************
# ********************************************************************************

# *** Main ***

if __name__ == '__main__':
    main()

# *** End of Program ***

# ********************************************************************************
# ********************************************************************************