MAX30100 Class Reference

API for the Pulse oximeter and heart-rate sensor. More...

Detailed Description

• ID: max30100
• Name: Pulse Oximeter and Heart-rate Sensor
• Category: medical
• Manufacturer: maxim
• Link: https://www.maximintegrated.com/en/products/analog/sensors-and-sensor-interface/MAX30100.html
• Connection: i2c gpio

The MAX30100 is an integrated pulse oximetry and heartrate monitor sensor solution. It combines two LEDs, a photodetector, optimized optics, and low-noise analog signal processing to detect pulse oximetry and heart-rate signals.

I2C sensor which can be used to read: Heart-rate Peripheral capillary oxygen saturation temperature

    // Instantiate a MAX30100 instance using i2c bus 0
    upm::MAX30100 sensor(0);

    // Create an instance of the Callback class
    mycallback cb;

    // Read the temperature and version
    std::cout << "Temperature: " << sensor.temperature() << " C" << std::endl;
    std::cout << "Version: " << sensor.version() << std::endl;

    // Set high-res (50 Hz, 16-bit)
    sensor.high_res_enable(true);

    // Set to sample SpO2
    sensor.mode(MAX30100_MODE_SPO2_EN);

    // Read continuously, stepping up the LED current every second,
    // us GPIO 0 as the interrupt pin
    sensor.sample_continuous(0, false, &cb);
    for (int i = MAX30100_LED_CURRENT_0_0_MA; i <= MAX30100_LED_CURRENT_50_0_MA && shouldRun; i++) {
        // Toggle the LED current
        std::cout << "Setting LED current = " << i << std::endl;

        sensor.current((MAX30100_LED_CURRENT) i, (MAX30100_LED_CURRENT) i);

        upm_delay(1);
    }

    // Read individual samples
    for (int i = 0; i < 10; i++) {
        max30100_value val = sensor.sample();
        std::cout << "Single value IR: " << val.IR << " R: " << val.R << std::endl;
    }

Public Member Functions
	MAX30100 (int16_t i2c_bus)
virtual	~MAX30100 ()
max30100_value	sample ()
void	sample_continuous (int gpio_pin, bool buffered, Callback *cb=NULL)
void	sample_stop ()
uint8_t	read (MAX30100_REG reg)
void	write (MAX30100_REG reg, uint8_t wr_data)
uint16_t	version ()
float	temperature ()
void	mode (MAX30100_MODE mode)
MAX30100_MODE	mode ()
void	high_res_enable (bool enable)
bool	high_res_enable ()
void	sample_rate (MAX30100_SR sample_rate)
MAX30100_SR	sample_rate ()
void	pulse_width (MAX30100_LED_PW pulse_width)
MAX30100_LED_PW	pulse_width ()
void	current (MAX30100_LED_CURRENT ir, MAX30100_LED_CURRENT r)
MAX30100_LED_CURRENT	current_ir ()
MAX30100_LED_CURRENT	current_r ()
void	reset ()
void	sleep (bool sleep)

Data Fields
Callback *	_callback

Constructor & Destructor Documentation

MAX30100

(

int16_t

i2c_bus

)

Oximeter and heart-rate sensor constructor

Initialize Oximeter and heart-rate sensor. Note, the I2C address is 0x57.

Parameters

i2c_bus

Target I2C bus

Returns

sensor context pointer

Exceptions

std::runtime_error

if sensor initialization fails

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virtual ~MAX30100 ( )

inlinevirtual

MAX30100 destructor

Member Function Documentation

max30100_value sample

(

)

Sample a single set of infrared/red values

Note, all setup (sample rate, LED current, and pulse width must be done prior to calling this sample method.

Returns

One IR/R sample

Exceptions

std::runtime_error

on I2C command failure

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void sample_continuous	(	int	gpio_pin,
		bool	buffered,
		Callback *	cb = NULL
	)

Continuously sample Infrared/Red values.

This method requires a GPIO pin which is used to signal sample/samples ready. The INT * pin is open-drain and requires a pullup resistor. The interrupt pin is not designed to sink large currents, so the pull-up resistor value should be large, such as 4.7k ohm. The RCWL-0530 PCB which this library was designed with had the I2C lines and INT pin pulled up to 1.8v.

Note, all setup (sample rate, mode, LED current, and pulse width must be done prior to calling this sample method.

Parameters

gpio_pin	GPIO pin for interrupt (input from sensor INT pin)
buffered	Enable buffered sampling. In buffered sampling mode, the device reads 16 samples at a time. This can help with I2C read timing. buffered == true, enable buffered sampling buffered == false, single-sample mode
cb	Pointer to instance of Callback class. If parameter is left NULL, a default instance of the Callback class will be used which prints out the IR/R values.

Exceptions

std::runtime_error

on I2C command failure

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void sample_stop

(

)

Stop continuous sampling. Disable interrupts.

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uint8_t read

(

MAX30100_REG

reg

)

Read Oximeter and heart-rate sensor registers

Parameters

reg	Target register to read

Returns

Data returned from sensor

Exceptions

std::runtime_error

if I2C read command fails

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void write	(	MAX30100_REG	reg,
		uint8_t	wr_data
	)

Write Oximeter and heart-rate sensor registers

Parameters

reg	Target register to write
wr_data	Target data to write

Exceptions

std::runtime_error

if I2C write command fails

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uint16_t version

(

)

Get sensor version Sensor version is a 2 byte value: upper byte = PART ID lower byte = REVISION ID

example: version() return 0x1105 0x11 = PART ID 0x05 = REVISION

Returns

Sensor version

Exceptions

std::runtime_error

on I2C command failure

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float temperature

(

)

Get temperature reading from device

Returns

rd_data Temperature in degrees Celsius

Exceptions

std::runtime_error

on I2C command failure

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void mode

(

MAX30100_MODE

mode

)

Set the sampling mode (none vs red only vs SpO2)

Parameters

mode	Target sampling mode

Exceptions

std::runtime_error

on I2C command failure

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MAX30100_MODE mode

(

)

Get the sampling mode

Returns

Current sampling mode

Exceptions

std::runtime_error

on I2C command failure

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void high_res_enable

(

bool

enable

)

Enable or disable high-resolution mode

Parameters

enable

High-resolution enable true == SpO2 ADC resolution of 16 bit with 1.6ms LED pw

Exceptions

std::runtime_error

on I2C command failure

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bool high_res_enable

(

)

Get the high-resolution enable bit

Returns

Current high-resolution bit value

Exceptions

std::runtime_error

on I2C command failure

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void sample_rate

(

MAX30100_SR

sample_rate

)

Set the sample rate

Parameters

sample_rate

Target sample rate

Exceptions

std::runtime_error

on I2C command failure

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MAX30100_SR sample_rate

(

)

Get the sample rate

Returns

Current sample rate

Exceptions

std::runtime_error

on I2C command failure

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void pulse_width

(

MAX30100_LED_PW

pulse_width

)

Set the LED pulse width

Parameters

pulse_width

Target LED pulse width

Exceptions

std::runtime_error

on I2C command failure

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MAX30100_LED_PW pulse_width

(

)

Get the LED pulse width

Returns

Current LED pulse width

Exceptions

std::runtime_error

on I2C command failure

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void current	(	MAX30100_LED_CURRENT	ir,
		MAX30100_LED_CURRENT	r
	)

Set the current for the infrared and red LEDs

Parameters

ir	LED current enum
r	LED current enum

Exceptions

std::runtime_error

on I2C command failure

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MAX30100_LED_CURRENT current_ir

(

)

Get the infrared LED current

Exceptions

std::runtime_error

on I2C command failure

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MAX30100_LED_CURRENT current_r

(

)

Get the red LED current

Exceptions

std::runtime_error

on I2C command failure

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void reset

(

)

Reset sensor

When the RESET bit is set to one, all configuration, threshold, and data registers are reset to their power-on-state. The only exception is writing both RESET and TEMP_EN bits to one at the same time since temperature data registers 0x16 and 0x17 are not cleared. The RESET bit is cleared automatically back to zero after the reset sequence is completed.

Exceptions

std::runtime_error

on I2C command failure

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void sleep

(

bool

sleep

)

Put device into power-save mode. While in power-save mode, all registers retain their values, and write/read operations function as normal. All interrupts are cleared to zero in this mode.

Parameters

sleep

Enter/exit power-save mode

Exceptions

std::runtime_error

on I2C command failure

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Collaboration diagram for MAX30100:

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The documentation for this class was generated from the following files:

• src/max30100/max30100.hpp
• src/max30100/max30100.cxx