SensorManager

MicroPythonOS provides a unified sensor framework called SensorManager, inspired by Android's SensorManager API. It provides easy access to motion sensors (accelerometer, gyroscope, magnetometer) and temperature sensors across different hardware platforms.

Overview

SensorManager automatically detects available sensors on your device:

QMI8658 IMU (Waveshare ESP32-S3-Touch-LCD-2)
WSEN_ISDS / LSM6DSO IMU (Fri3d Camp 2024/2026)
MPU6886 IMU (M5Stack Fire)
Linux IIO (Desktop builds with IIO sensors)
ESP32 MCU Temperature (All ESP32 boards)

The framework handles:

Auto-detection - Identifies which IMU is present
Unit normalization - Returns standard SI units (m/s², deg/s, °C, μT)
Persistent calibration - Calibrate once, saved across reboots
Thread-safe - Safe for concurrent access
Hardware-agnostic - Apps work on all platforms without changes

Sensor Types

from mpos import SensorManager

# Motion sensors
SensorManager.TYPE_ACCELEROMETER    # m/s² (meters per second squared)
SensorManager.TYPE_GYROSCOPE        # deg/s (degrees per second)
SensorManager.TYPE_MAGNETIC_FIELD   # μT (micro teslas)

# Temperature sensors
SensorManager.TYPE_SOC_TEMPERATURE  # °C (MCU internal temperature)
SensorManager.TYPE_IMU_TEMPERATURE  # °C (IMU chip temperature)

Quick Start

Basic Usage

from mpos import Activity, SensorManager

class MyActivity(Activity):
    def onCreate(self):
        if not SensorManager.is_available():
            print("No sensors available")
            return

        self.accel = SensorManager.get_default_sensor(SensorManager.TYPE_ACCELEROMETER)
        self.gyro = SensorManager.get_default_sensor(SensorManager.TYPE_GYROSCOPE)

        accel_data = SensorManager.read_sensor(self.accel)
        gyro_data = SensorManager.read_sensor(self.gyro)

Reading Temperature

# Get MCU internal temperature (most stable)
temp_sensor = SensorManager.get_default_sensor(SensorManager.TYPE_SOC_TEMPERATURE)
temperature = SensorManager.read_sensor(temp_sensor)

# Get IMU chip temperature
imu_temp_sensor = SensorManager.get_default_sensor(SensorManager.TYPE_IMU_TEMPERATURE)
imu_temperature = SensorManager.read_sensor(imu_temp_sensor)

Desktop/Linux IIO Support

On desktop builds, SensorManager can use Linux IIO sensors:

from mpos import SensorManager

SensorManager.init_iio()
mag = SensorManager.get_default_sensor(SensorManager.TYPE_MAGNETIC_FIELD)
print(SensorManager.read_sensor(mag))

Calibration

Calibration removes sensor drift and improves accuracy. The device must be stationary on a flat surface during calibration.

Manual Calibration (Programmatic)

accel = SensorManager.get_default_sensor(SensorManager.TYPE_ACCELEROMETER)
gyro = SensorManager.get_default_sensor(SensorManager.TYPE_GYROSCOPE)

accel_offsets = SensorManager.calibrate_sensor(accel, samples=100)
gyro_offsets = SensorManager.calibrate_sensor(gyro, samples=100)

Calibration is saved to imu_calibration.json under com.micropythonos.settings.

List Available Sensors

sensors = SensorManager.get_sensor_list()
for sensor in sensors:
    print(sensor.name, sensor.type, sensor.vendor)

API Reference

Functions

init(i2c_bus, address=0x6B, mounted_position=FACING_SKY)

Initialize SensorManager. Returns True if initialization succeeded.

init_iio()

Initialize Linux IIO sensors (desktop builds).

is_available()

Returns True if sensors are available.

get_sensor_list()

Returns list of all available Sensor objects.

get_default_sensor(sensor_type)

Returns the default Sensor for the given type, or None if not available.

read_sensor(sensor)

Reads sensor data. Returns (x, y, z) tuple for motion sensors, single value for temperature, or None on error.

read_sensor_once(sensor)

One-shot sensor read with automatic initialization (used internally by calibration helpers).

calibrate_sensor(sensor, samples=100)

Calibrates the sensor (device must be stationary). Returns calibration offsets and saves them to disk.

check_calibration_quality(samples=50)

Return a dict containing mean/variance statistics and a quality score.

check_stationarity(samples=30, variance_threshold_accel=0.5, variance_threshold_gyro=5.0)

Return True if the device appears stationary based on variance thresholds.

Sensor Object

Properties:

name - Human-readable sensor name
type - Sensor type constant
vendor - Manufacturer name
version - Driver version
max_range - Maximum measurement range
resolution - Measurement resolution
power - Power consumption in mA