MicroPython BMA220 Library¶

bma220¶

MicroPython Driver for the Bosch BMA220 Accelerometer

• Author(s): Jose D. Montoya

class micropython_bma220.bma220.BMA220(i2c, address: int = 0x0A)[source]¶

Driver for the BMA220 Sensor connected over I2C.

Parameters:¶

i2c : I2C¶

The I2C bus the BMA220 is connected to.

address : int¶

The I2C device address. Defaults to 0x0A

Raises:¶

RuntimeError – if the sensor is not found

Quickstart: Importing and using the device

Here is an example of using the BMA220 class. First you will need to import the libraries to use the sensor

from machine import Pin, I2C
from micropython_bma220 import bma220

Once this is done you can define your machine.I2C object and define your sensor object

i2c = I2C(1, sda=Pin(2), scl=Pin(3))
bma220 = bma220.BMA220(i2c)

Now you have access to the attributes

accx, accy, accz = bma220.acceleration

property acc_range : str¶

The BMA220 has four different range settings for the full scale acceleration range. In dependence of the use case always the lowest full scale range with the maximum resolution should be selected. Please refer to literature to find out, which full scale acceleration range, which sensitivity or which resolution is the ideal one.

Mode	Value
bma220.ACC_RANGE_2	0b00
bma220.ACC_RANGE_4	0b01
bma220.ACC_RANGE_8	0b10
bma220.ACC_RANGE_16	0b11

property acceleration : tuple[float, float, float]¶

Acceleration :return: acceleration x, y, z in m/s²

property filter_bandwidth : str¶

The BMA220 has a digital filter that can be configured. To always ensure

an ideal cut off frequency of the filter the BMA220 is adjusting the sample rate automatically.

Mode	Value
bma220.ACCEL_32HZ	0x05
bma220.ACCEL_64HZ	0x04
bma220.ACCEL_125HZ	0x03
bma220.ACCEL_250HZ	0x02
bma220.ACCEL_500HZ	0x01
bma220.ACCEL_1000HZ	0x00

property latched_mode : str¶

Sensor latched_mode

The interrupt controller can be used in two modes

• Latched mode: Once one of the configured interrupt conditions applies, the INT pin is asserted and must be reset by the external master through the digital interface.

• Non-Latched mode: The interrupt controller clears the INT signal once the interrupt condition no longer applies.

The interrupt output can be programmed by latched_mode to be either unlatched (‘000’) or latched permanently (‘111’) or have different latching times.

Mode	Value
bma220.UNLATCHED	0b000
bma220.LATCH_FOR_025S	0b001 0.25 seconds
bma220.LATCH_FOR_050S	0b010 0.5 seconds
bma220.LATCH_FOR_1S	0b011 1 second
bma220.LATCH_FOR_2S	0b100 2 seconds
bma220.LATCH_FOR_4S	0b101 4 seconds
bma220.LATCH_FOR_8S	0b110 8 seconds
bma220.LATCHED	0b111

property sleep_duration : str¶

Sensor sleep_duration.

Mode	Value
bma220.SLEEP_2MS	0b000
bma220.SLEEP_10MS	0b001
bma220.SLEEP_25MS	0b010
bma220.SLEEP_50MS	0b011
bma220.SLEEP_100MS	0b100
bma220.SLEEP_500MS	0b101
bma220.SLEEP_1S	0b110
bma220.SLEEP_2S	0b111

property sleep_enabled : str¶

The BMA220 supports a low-power mode. In this low-power mode, the chip wakes up periodically, enables the interrupt controller and goes back to sleep if no interrupt has occurred. The low-power mode can be enabled by setting sleep_enabled and by enabling the data ready interrupt (or any other interrupt, see chapter 5 in the datasheet)

Mode	Value
bma220.SLEEP_DISABLED	0b0
bma220.SLEEP_ENABLED	0b1

property x_enabled : str¶

Sensor x_enabled In order to optimize further power consumption of the BMA220, data evaluation of individual axes can be deactivated. Per default, all three axes are active.

Mode	Value
bma220.X_DISABLED	0b0
bma220.X_ENABLED	0b1

property y_enabled : str¶

Sensor y_enabled In order to optimize further power consumption of the BMA220, data evaluation of individual axes can be deactivated. Per default, all three axes are active.

Mode	Value
bma220.Y_DISABLED	0b0
bma220.Y_ENABLED	0b1

property z_enabled : str¶

Sensor z_enabled In order to optimize further power consumption of the BMA220, data evaluation of individual axes can be deactivated. Per default, all three axes are active.

Mode	Value
bma220.Z_DISABLED	0b0
bma220.Z_ENABLED	0b1