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JensDiemer
93c2317a5d
MPU6886 is part of M5Stack FIRE. I compare the values from this device with Waveshare ESP32-S3-Touch-LCD-2: The X-axis values are inverted. Fix this here.
84 lines
2.6 KiB
Python
84 lines
2.6 KiB
Python
"""
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MicroPython driver for MPU6886 3-Axis Accelerometer + 3-Axis Gyroscope.
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Tested with M5Stack FIRE
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https://docs.m5stack.com/en/unit/imu
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https://github.com/m5stack/M5Stack/blob/master/src/utility/MPU6886.h
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"""
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import time
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from machine import I2C
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from micropython import const
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_I2CADDR_DEFAULT = const(0x68)
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# register addresses
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_REG_PWR_MGMT_1 = const(0x6B)
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_REG_ACCEL_XOUT_H = const(0x3B)
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_REG_GYRO_XOUT_H = const(0x43)
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_REG_ACCEL_CONFIG = const(0x1C)
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_REG_GYRO_CONFIG = const(0x1B)
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_REG_TEMPERATURE_OUT_H = const(0x41)
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# Scale factors for converting raw sensor data to physical units:
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_ACCEL_SCALE_8G = 8.0 / 32768.0 # LSB/g for +-8g range
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_GYRO_SCALE_2000DPS = 2000.0 / 32768.0 # LSB/°/s for +-2000dps range
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_TEMPERATURE_SCALE = 326.8 # LSB/°C
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_TEMPERATURE_OFFSET = const(25) # Offset (25°C at 0 LSB)
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def twos_complement(val, bits):
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if val & (1 << (bits - 1)):
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val -= 1 << bits
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return val
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class MPU6886:
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def __init__(
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self,
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i2c_bus: I2C,
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address: int = _I2CADDR_DEFAULT,
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):
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self.i2c = i2c_bus
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self.address = address
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for data in (b"\x00", b"\x80", b"\x01"): # Reset, then wake up
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self._write(_REG_PWR_MGMT_1, data)
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time.sleep(0.01)
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self._write(_REG_ACCEL_CONFIG, b"\x10") # +-8g
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time.sleep(0.001)
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self._write(_REG_GYRO_CONFIG, b"\x18") # +-2000dps
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time.sleep(0.001)
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# Helper functions for register operations
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def _write(self, reg: int, data: bytes):
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self.i2c.writeto_mem(self.address, reg, data)
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def _read_xyz(self, reg: int, scale: float) -> tuple[int, int, int]:
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data = self.i2c.readfrom_mem(self.address, reg, 6)
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x = twos_complement(data[0] << 8 | data[1], 16) * -1
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y = twos_complement(data[2] << 8 | data[3], 16)
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z = twos_complement(data[4] << 8 | data[5], 16)
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return (x * scale, y * scale, z * scale)
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@property
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def temperature(self) -> float:
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buf = self.i2c.readfrom_mem(self.address, _REG_TEMPERATURE_OUT_H, 14)
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temp_raw = (buf[6] << 8) | buf[7]
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if temp_raw & 0x8000: # If MSB is 1, it's negative
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temp_raw -= 0x10000 # Subtract 2^16 to get negative value
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return temp_raw / _TEMPERATURE_SCALE + _TEMPERATURE_OFFSET
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@property
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def acceleration(self) -> tuple[int, int, int]:
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"""Get current acceleration reading."""
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return self._read_xyz(_REG_ACCEL_XOUT_H, scale=_ACCEL_SCALE_8G)
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@property
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def gyro(self) -> tuple[int, int, int]:
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"""Get current gyroscope reading."""
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return self._read_xyz(_REG_GYRO_XOUT_H, scale=_GYRO_SCALE_2000DPS)
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