IIS2DULPX – Measuring acceleration (MicroPython)

This page contains examples with function documentation on how to use the IIS2DULPX Accelerometer breakout with MicroPython.

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Initialization

Copy iis2dulpx.py to your board's filesystem, then import it and create the sensor object. Call begin() to verify the sensor is connected and configure it:

from iis2dulpx import IIS2DULPX, IIS2DULPX_OK

# Uses default I2C pins (SCL=22, SDA=21) and address 0x18
sensor = IIS2DULPX()

if sensor.begin() != IIS2DULPX_OK:
    raise Exception("Failed to initialize IIS2DULPX sensor")

if sensor.Enable_X() != IIS2DULPX_OK:
    raise Exception("Failed to enable accelerometer")

print("IIS2DULPX initialized successfully.")

If you are wiring manually or using different I2C pins, pass the I2C object explicitly:

from machine import I2C, Pin
from iis2dulpx import IIS2DULPX, IIS2DULPX_OK

i2c = I2C(0, scl=Pin(22), sda=Pin(21))
sensor = IIS2DULPX(i2c)

sensor.begin()

Reads the WHO_AM_I register to verify the sensor, then configures BDU, disables I3C, sets FIFO to bypass mode, and powers the accelerometer down. Must be called before any other method.

Returns value: Returns `IIS2DULPX_OK` (0) on success, `IIS2DULPX_ERROR` (-1) if the sensor is not found or cannot be configured.

sensor.Enable_X()

Powers on the accelerometer and begins acquiring data at the configured ODR and full scale.

Returns value: Returns `IIS2DULPX_OK` (0) on success, `IIS2DULPX_ERROR` (-1) on failure.

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Reading acceleration data

Once the accelerometer is enabled, call Get_X_Axes() to get the current acceleration for all three axes in mg (milli-g):

import time

while True:
    x, y, z = sensor.Get_X_Axes()
    print("Accel-X [mg]:{},Accel-Y[mg]:{},Accel-Z[mg]:{}".format(x, y, z))
    time.sleep_ms(50)

sensor.Get_X_Axes()

Reads the raw 16-bit acceleration output registers and converts the values to mg using the currently configured full-scale sensitivity.

Returns value: Returns a tuple `(x, y, z)` where each value is an integer in mg (milli-g).

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Configuring full scale and ODR

You can change the measurement range and output data rate to suit your application:

from iis2dulpx import IIS2DULPX, IIS2DULPX_OK, IIS2DULPX_HIGH_PERFORMANCE

# Set full scale to ±8g
sensor.Set_X_FullScale(8)

# Set ODR to 200 Hz in High Performance mode
sensor.Set_X_OutputDataRate_With_Mode(200.0, IIS2DULPX_HIGH_PERFORMANCE)

sensor.Set_X_FullScale(full_scale)

Configures the accelerometer full-scale range. Automatically selects the nearest supported range.

Returns value: Returns `IIS2DULPX_OK` (0) on success, `IIS2DULPX_ERROR` (-1) on failure.

Function parameters:

Type	Name	Description
int	full_scale	Desired range in g. Accepted values: 2, 4, 8, 16.

sensor.Set_X_OutputDataRate_With_Mode(odr, power_mode)

Sets the output data rate and power mode simultaneously. The ODR is rounded up to the nearest supported rate for the selected mode.

Returns value: Returns `IIS2DULPX_OK` (0) on success, `IIS2DULPX_ERROR` (-1) on failure.

Function parameters:

Type	Name	Description
float	odr	Desired output data rate in Hz (e.g. 1.6, 6.0, 12.5, 25.0, 50.0, 100.0, 200.0, 400.0, 800.0).
int	power_mode	Power mode constant: IIS2DULPX_ULTRA_LOW_POWER, IIS2DULPX_LOW_POWER, or IIS2DULPX_HIGH_PERFORMANCE.

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Full example — Serial Plotter

This example continuously reads X/Y/Z acceleration and prints values in a format compatible with serial plotters:

# FILE: iis2dulpx-serialPlotter.py
# AUTHOR: Josip Simun Kuci @ Soldered
# BRIEF: Poll IIS2DULPX acceleration values for serial plotting
# WORKS WITH: IIS2DULPX Accelerometer breakout: www.solde.red/333363

from machine import I2C, Pin
from iis2dulpx import IIS2DULPX, IIS2DULPX_OK
import time

# If you are not using the Qwiic connector, manually enter your I2C pins
# i2c = I2C(0, scl=Pin(22), sda=Pin(21))
# sensor = IIS2DULPX(i2c)

sensor = IIS2DULPX()

if sensor.begin() != IIS2DULPX_OK:
    raise Exception("Failed to initialize IIS2DULPX sensor")

if sensor.Enable_X() != IIS2DULPX_OK:
    raise Exception("Failed to enable accelerometer")

print("IIS2DULPX sensor initialized and accelerometer enabled.")

while True:
    x, y, z = sensor.Get_X_Axes()
    print("Accel-X [mg]:{},Accel-Y[mg]:{},Accel-Z[mg]:{}".format(x, y, z))
    time.sleep_ms(50)

iis2dulpx-serialPlotter.py

Continuously polls X/Y/Z acceleration and outputs it for serial plotting.

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Interrupt-based wake-up detection

The IIS2DULPX can generate an interrupt on INT1 or INT2 when motion above a threshold is detected. In MicroPython, use Pin.irq() to attach a callback:

# FILE: iis2dulpx-interruptWakeup.py
# AUTHOR: Josip Simun Kuci @ Soldered
# BRIEF: Use IIS2DULPX wake-up interrupt to detect movement
# WORKS WITH: IIS2DULPX Accelerometer breakout: www.solde.red/333363

from machine import Pin, I2C
from iis2dulpx import IIS2DULPX, IIS2DULPX_OK, IIS2DULPX_INT1_PIN
import time

# Hardware setup:
# - Connect breakout INT1 pin to INT1_PIN below
# - Optional: connect a buzzer or LED to ALERT_PIN
INT1_PIN = 5
ALERT_PIN = 23

mems_event = False


def int1_callback(pin):
    global mems_event
    mems_event = True


# If you are not using the Qwiic connector, manually enter your I2C pins
# i2c = I2C(0, scl=Pin(22), sda=Pin(21))
# sensor = IIS2DULPX(i2c)

sensor = IIS2DULPX()
alert = Pin(ALERT_PIN, Pin.OUT)
int1 = Pin(INT1_PIN, Pin.IN)
int1.irq(trigger=Pin.IRQ_RISING, handler=int1_callback)

if sensor.begin() != IIS2DULPX_OK:
    raise Exception("Failed to initialize IIS2DULPX sensor")

if sensor.Enable_X() != IIS2DULPX_OK:
    raise Exception("Failed to enable accelerometer")

if sensor.Enable_Wake_Up_Detection(IIS2DULPX_INT1_PIN) != IIS2DULPX_OK:
    raise Exception("Failed to enable wake-up detection")

print("Wake-up detection enabled")

while True:
    if mems_event:
        mems_event = False
        status = sensor.Get_X_Event_Status()
        if status["WakeUpStatus"]:
            print("Wake up Detected!")
            alert.on()
            time.sleep_ms(200)
            alert.off()

    time.sleep_ms(10)

sensor.Enable_Wake_Up_Detection(int_pin)

Enables wake-up detection. Configures the sensor to generate an interrupt on the specified pin when acceleration exceeds the default wake-up threshold. Also sets ODR to 200 Hz and full scale to ±2g.

Returns value: Returns `IIS2DULPX_OK` (0) on success, `IIS2DULPX_ERROR` (-1) on failure.

Function parameters:

Type	Name	Description
int	int_pin	Interrupt pin to route the event to: `IIS2DULPX_INT1_PIN` or `IIS2DULPX_INT2_PIN`.

sensor.Get_X_Event_Status()

Reads the interrupt source registers and returns a dictionary of event flags.

Returns value: Returns a dict with keys `"WakeUpStatus"`, `"FreeFallStatus"`, `"TapStatus"`, `"DoubleTapStatus"`, `"D6DOrientationStatus"`, `"StepStatus"`, `"TiltStatus"`, `"SleepStatus"`. Each value is `1` if the event is active, `0` otherwise.

sensor.Set_Wake_Up_Threshold(threshold_mg)

Sets the wake-up detection threshold in mg. Automatically selects the appropriate resolution based on the current full-scale setting.

Returns value: Returns `IIS2DULPX_OK` (0) on success, `IIS2DULPX_ERROR` (-1) on failure.

Function parameters:

Type	Name	Description
float	threshold_mg	Wake-up threshold in mg.

iis2dulpx-interruptWakeup.py

Uses INT1 to detect motion and toggle an output pin on wake-up.