Introduction
This Fermion IMU sensor is a high-precision 9-degree-of-freedom (DOF) inertial measurement unit designed around the Bosch BMI323 6-axis MEMS sensor and BMM350 3-axis magnetometer. This multi-DOF sensor integrates a 3-axis accelerometer, 3-axis gyroscope, and 3-axis magnetometer into a compact 24mm × 19mm module, delivering comprehensive spatial attitude detection for advanced motion-sensing applications. The built-in hardware motion engine accurately captures acceleration, angular velocity, orientation, and real-time spatial attitude while effectively addressing the data drift issues that plague pure inertial devices during extended operation.
High Performance, High Accuracy, High Stability
This high-precision IMU sensor leverages the BMI323's low-noise hardware architecture and on-chip temperature compensation to minimize data deviations caused by environmental interference. Accelerometer bias reaches ±35 mg with gyroscope bias of ±1 °/s, delivering reliable and consistent measurements across diverse operating conditions. The integrated 2 KB FIFO buffer ensures continuous and stable data transmission at high sampling rates without data loss. The BMM350 magnetometer utilizes Bosch's 3rd-generation TMR magnetoresistive technology, reducing noise to one-third of previous-generation sensors with magnetic field shock recovery under 10 ms. After calibration, this 9-axis sensor outputs stable orientation data that remains accurate over time.
Built-in Hardware Motion Algorithms – No Extra Development
The integrated intelligent motion processor directly outputs detection results including step counting, tap detection, tilt sensing, free-fall recognition, and activity classification without consuming host controller resources. This hardware-accelerated attitude calculation capability enables quick integration of common motion interaction features, significantly reducing development time for Arduino, Raspberry Pi, and ESP32 projects.
Flexible Configuration, Controllable Power Consumption
This 9-DOF motion sensor offers configurable accelerometer and gyroscope measurement ranges with a maximum output data rate of 6400 Hz, while the magnetometer supports sampling rates up to 400 Hz to accommodate varying accuracy and response speed requirements. Multiple operating modes—Sleep, Low Power, Normal, and High Performance—provide flexibility for different use cases, with Low Power mode consuming only 0.37 mA to extend battery life in portable and wearable devices.
BMI323 Multi-DOF IMU Sensor Series
From 6-axis motion sensing to 10-axis altitude-aware orientation.
6DOF Motion: Acceleration + Gyroscope. For tilt detection, gesture input, vibration sensing, rotation tracking, and basic motion feedback.9DOF Heading: Motion + Magnetometer. For projects that need motion sensing with magnetic heading reference, orientation correction, or electronic compass functionality.10DOF Altitude: Motion + Heading + Barometer. For applications that require acceleration, rotation, magnetic heading, and barometric pressure or altitude-related data.
Choose by Form Factor
Gravity: Easier wiring, I2C/UART, rapid prototyping
Fermion: Compact size, I2C, embedded integration
Features
Designed based on Bosch BMI323 6-axis IMU + BMM350 3-axis magnetometer for 9-axis sensing
High-accuracy, high-stability output with built-in low-noise architecture and on-chip temperature compensation
Built-in hardware motion algorithms including step counting, tap detection, tilt sensing, free-fall, and activity recognition
Integrated 2048-byte FIFO buffer ensures high-speed data transmission without loss
Magnetometer employs 3rd-generation TMR technology with enhanced interference immunity and fast recovery
Supports multiple operating modes including Sleep, Low Power, Normal, and High Performance – Low Power mode consumes only 0.37 mA
Onboard I²C interface supports both soldered and plug-in connection methods for flexible integration
Compatible with mainstream development boards including Arduino, Raspberry Pi, and ESP32 with complete development libraries
Specification
Basic Parameters
Operating Voltage: 3.3 V
Operating Current: 0.92 mA
Low Power Current: 0.37 mA
Communication Interface: I²C
Connector Type: SH1.0-5P connector / 2.54 mm pin header holes
I²C Addresses:
BMI323: 0x69 (default), 0x68
BMM350: 0x15 (default), 0x14
Programmable Interrupt Pins: ×3
BMI323 Parameters
Accelerometer Measurement Ranges: ±2 g, ±4 g, ±8 g, ±16 g
Accelerometer ADC Resolution: 16-bit
Accelerometer Sensitivity:
±2 g range: 16384 LSB/g
±4 g range: 8192 LSB/g
±8 g range: 4096 LSB/g
±16 g range: 2048 LSB/g
Accelerometer Sensitivity Error: ±0.5%
Accelerometer Zero-g Offset: ±50 mg
Accelerometer Output Data Rate (ODR):
High Performance / Normal mode: 12.5 Hz ~ 6400 Hz
Low Power mode: 0.78125 Hz ~ 400 Hz
Gyroscope Angular Rate Ranges: ±125, ±250, ±500, ±1000, ±2000 °/s
Gyroscope ADC Resolution: 16-bit
Gyroscope Sensitivity:
±2000 °/s range: 16.384 LSB/(°/s)
±1000 °/s range: 32.768 LSB/(°/s)
±500 °/s range: 65.536 LSB/(°/s)
±250 °/s range: 131.072 LSB/(°/s)
Gyroscope Sensitivity Error: ±3% (without self-calibration), ±0.7% (after self-calibration)
Gyroscope Zero-Rate Offset: ±1 °/s
Gyroscope Output Data Rate (ODR):
High Performance / Normal mode: 12.5 Hz ~ 6400 Hz
Low Power mode: 0.78125 Hz ~ 400 Hz
BMM350 Parameters
Operating Modes: Normal periodic measurement, triggered forced measurement, low-power sleep standby
Measurement Range: ±2000 µT
Magnetic Field Resolution: approx. 0.1 µT
Zero-Field Offset Drift: ±2 µT (-40 °C ~ +85 °C, after calibration)
X/Y-Axis Gain Error: ±1% (25 °C, after API compensation)
Z-Axis Gain Error: ±3% (25 °C, after API compensation)
Sensitivity Temperature Drift: ±0.010 %/K
Offset Temperature Error: ±200 nT/K
Normal Mode Output Data Rate: 400/200/100/50/25/12.5/6.25/3.125/1.5625 Hz, typical deviation ±2%
Forced Mode Maximum Trigger Frequency: 200 Hz (avg=0 only)
X/Y-Axis Output Noise: 190 nTrms
Z-Axis Output Noise: 450 nTrms
Physical Dimensions
PCB Size: 24 mm × 19 mm
Mounting Hole Spacing: 19 mm
Mounting Hole Diameter: 2 mm
Shipping List
Fermion: BMI323+BMM350 High Precision 9 DOF IMU Sensor ×1
SH1.0-5P Sensor Cable ×1
2.54 mm Black Single Row Pin Header – 10-Pin ×1
Applications
Indoor inertial navigation and positioning systems
Drone heading control and flight stabilization
Robot localization and autonomous navigation
Electronic compass and orientation sensing
Wearable devices and motion tracking
Motion controllers and gesture recognition
Micro-robot attitude monitoring and balance control
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