Gravity: 9 DOF IMU Sensor

SKU: SEN0694

The Gravity: 9 DOF IMU Sensor integrates a 3-axis accelerometer, gyroscope, and magnetometer, providing advanced motion detection and accurate spatial orientation. It supports I2C and UART communication, ideal for various projects. With open-source Arduino and Python code, it's perfect for enthusiasts seeking comprehensive motion tracking in their applications. Explore features like step counting, tilt detection, and Euler angle calculations.

Downloadable Resources

  • Docs
  • Tech Specs
  • 1. Example Code for Arduino-Reading Data via I2C

    This tutorial demonstrates how to initialize a 9 DOF IMU sensor and directly read acceleration, angular velocity, and magnetometer data using the polling method.

    2. Example Code for Arduino-Reading Data via UART and Interrupts

    This tutorial demonstrates how to configure a 9 DOF IMU sensor to trigger a hardware interrupt when data is ready, and read acceleration, angular velocity, and magnetometer data in the interrupt service routine to achieve efficient data acquisition.

    3. Usage Example for Host Computer Software

    This guide provides a detailed walkthrough on connecting the 9 DOF IMU sensor to the RainbowLink V2 using host computer software. The process includes hardware and software setup, configuring communication modes, and collecting real-time data such as acceleration and gyroscope values.

    4. Modbus Register Definitions

    This guide details Modbus Register Definitions, covering both input and holding registers. Learn about function codes and how to read 3-axis acceleration data from a 9DOF IMU sensor.

    Reference

    Specification

    Basic Parameters

    Parameter Value
    Operating Voltage DC 3.3–5 V
    Operating Current 3.42 mA
    Communication Interface I2C / UART
    Interface Type PH2.0-4P (Gravity pin order) / 2.54 mm pin header
    I2C Address 0x4A (default) / 0x4B / 0x4C / 0x4D
    Programmable Interrupt Pins BMI323: 2 channelsBMM350: 1 channel

    Accelerometer Parameters

    Parameter Value
    Measurement Range ±2 g, ±4 g, ±8 g, ±16 g
    ADC Resolution 16-bit
    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
    Sensitivity Error ±0.5%
    Zero-g Offset ±50 mg
    Output Data Rate (ODR) High Performance / Normal Mode: 12.5 Hz ~ 6400 HzLow Power Mode: 0.78125 Hz ~ 400 Hz

    Gyroscope Parameters

    Parameter Value
    Angular Velocity Range ±125, ±250, ±500, ±1000, ±2000 °/s
    ADC Resolution 16-bit
    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)
    Sensitivity Error ±3% (without auto‑calibration) / ±0.7% (after auto‑calibration)
    Zero-rate Offset ±1 °/s
    Output Data Rate (ODR) High Performance / Normal Mode: 12.5 Hz ~ 6400 HzLow Power Mode: 0.78125 Hz ~ 400 Hz

    Magnetometer Parameters

    Parameter Value
    Operating Modes Normal mode (periodic measurement), Forced mode (triggered measurement), Sleep mode (low-power standby)
    Measurement Range ±2000 µT
    Magnetic Resolution ~0.1 µT
    Zero-field Offset Drift (after soldering)Zero-field Offset (after calibration) ±2 µT (-40 °C ~ +85 °C, calibrated with Bosch eCompass software)
    X/Y Axis Gain Error ±1% (25 °C, after API compensation)
    Z Axis Gain Error ±3% (25 °C, after API compensation)
    Temperature Coefficient of Sensitivity (TCS) ±0.010 %/K
    Temperature Offset Error (TCOerr) ±200 nT/K
    Normal Mode ODR 400 / 200 / 100 / 50 / 25 / 12.5 / 6.25 / 3.125 / 1.5625 Hz (typical tolerance ±2%)
    Max Trigger Frequency in Forced Mode 200 Hz (only when avg=0)
    X/Y Axis Output Noise (rms) 190 nTrms (ODR=100 Hz, 2 samples averaged, 3 dB bandwidth = ODR/2)
    Z Axis Output Noise (rms) 450 nTrms (ODR=100 Hz, 2 samples averaged, 3 dB bandwidth = ODR/2)

    Physical Dimensions

    Parameter Value
    PCB Size 32 mm × 27 mm
    Mounting Hole Spacing 20 mm
    Mounting Hole Diameter 3 mm

    Pinout

    SEN0694-Pinout

    Interface Pin Description

    Pin Silkscreen Function Description
    + Positive Power Supply (Input: 3.3–5 V)
    - Negative Power Supply (GND)
    C/R Multifunction Pin: SCL in I2C mode, RXD in UART mode
    D/T Multifunction Pin: SDA in I2C mode, TXD in UART mode
    INT1 BMI323 Interrupt Output Pin 1
    INT2 BMI323 Interrupt Output Pin 2
    INT3 BMM350 Interrupt Output Pin

    I2C Address Setting Switch Description

    I2C Address A0 A1
    0x4A 0 0
    0x4B 1 0
    0x4C 0 1
    0x4D 1 1

    Notes

    • The setting of the I2C/UART Switch is saved when powered off. The new mode takes effect after restarting the device.

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