GY-91 10DOF MPU9250 and BMP280 IMU Accelerometer Gyro Barometer Sensor Module

Specifications

• Sensor Suite: MPU-9250 (9-Axis) + BMP280 (Pressure/Altimeter)
• Degrees of Freedom (DOF): 10 Total
• Operating Voltage: 3.0V - 5.0V (On-board Ultra-low noise regulator)
• Communication Interface: Standard I2C and High-Speed SPI (up to 20MHz)
• AD Converter: Internal 16-bit ADC for all channels
• Gyroscope Range: Programmable $\pm 250, \pm 500, \pm 1000, \pm 2000$ °/s
• Accelerometer Range: Programmable $\pm 2g, \pm 4g, \pm 8g, \pm 16g$
• Magnetometer Range: $\pm 4800 \mu T$ (Full scale)
• Pressure Range: 300 to 1100 hPa (equiv. to +9000m to -500m above/below sea level)
• Dimensions:14.3mm \times 20.5mm
• Pin Pitch: 2.54mm (Breadboard Friendly)

Applications

• Drones & UAVs: The core IMU for flight controllers (Betaflight/iNav) requiring altitude hold.
• Robotic Navigation: Simultaneous Localization and Mapping (SLAM) and dead reckoning.
• Wearable Tech: High-fidelity gesture recognition and motion capture suits.
• IoT Weather Stations: Combining altitude data with temperature and pressure for localized forecasting.
• Rocketry: High-G acceleration tracking and apogee detection via pressure sensing.

Unlock New Capabilities

• The Starting Point: If you have used the basic MPU-6050, you know it lacks a compass (magnetometer) and barometer, leading to "heading drift" and "altitude wandering."
• The GY-91 Upgrade: Moving to the GY-91 unlocks True North alignment and sub-meter altitude precision. You can now build stabilized drones that don't just know they are level, but know exactly where they are pointing and how high they are.
• Effort Level: Intermediate. Requires knowledge of I2C/SPI bus addressing and sensor fusion libraries (like Madgwick or Mahony filters).

Virtual Technician & Wiring

• ⚠️ Safety Warning: While the module supports 5V input for power, the logic pins on many GY-91 modules are not strictly 5V tolerant for SPI high-speed communication. We recommend using a logic level converter when interfacing with 5V boards like the Arduino Uno to prevent long-term degradation.

Pin Mapping (I2C Mode):

• VIN: 3.3V - 5V DC
• GND: Ground
• SCL: I2C Clock / SPI Clock
• SDA: I2C Data / SPI MOSI
• SDO/AD0: SPI MISO / I2C Address Select
• CS: Chip Select (Pull High for I2C)

Package Includes :

• 1 x GY-91 10DOF MPU9250 and BMP280 IMU Accelerometer Gyro Barometer Sensor Module

Frequently Asked Questions (FAQ)

• What is the default I2C address for the GY-91?
  Typically $0x68$ for the MPU-9250 and $0x76$ for the BMP280.
• Can I use SPI and I2C at the same time?
  No, you must choose one protocol based on the wiring of the CS and AD0 pins.
• Does the GY-91 work with 5V Arduino boards?
  Yes, but use the VIN pin for power and a level shifter for data lines for best reliability.
• How do I calibrate the magnetometer?
  You must perform a "figure-8" motion in a space free of local magnetic interference using calibration software.
• What is the difference between MPU-9250 and MPU-9255?
  The 9250 is the standard version used in the GY-91; the 9255 has minor internal register differences but is mostly compatible.
• Why is my altitude reading fluctuating?
  Airflow over the BMP280 can cause noise; cover the sensor with a small piece of open-cell foam for stability.
• Is the GY-91 compatible with Raspberry Pi?
  Yes, it works perfectly via the I2C bus using Python libraries.
• What library should I use for Arduino?
  The "MPU9250_WE" or the Kris Winer library are highly recommended.
• Does it include a temperature sensor?
  Yes, both the MPU-9250 and the BMP280 have internal temperature sensors.
• What is the sampling rate of the Gyro?
  Up to 8kHz, though I2C limitations usually cap practical usage lower.
• How many wires are needed for I2C?
  Four: VIN, GND, SDA, and SCL.
• Can this be used for a self-balancing robot?
  Absolutely, it is ideal for balancing applications due to the high-speed gyro.
• Is the header pre-soldered?
  Usually, it comes with an unsoldered header to allow for custom mounting.
• What is the pressure resolution of the BMP280?
  0.16 Pa, which equates to roughly 13cm of altitude change.
• Does the module have an interrupt pin?
  Yes, the INT pin can signal data ready or motion detection.
• How do I reduce noise in my orientation data?
  Implement a Madgwick or Kalman filter in your code.
• Can I use this module for high-altitude balloons?
  Yes, it is rated up to 1100hPa to 300hPa (approx 9,000m).
• What is the current consumption?
  Very low, typically under 5mA in full operation.
• Can I connect multiple GY-91s to one I2C bus?
  Yes, by toggling the AD0 pin to change the I2C address.
• Is this sensor fusion done on-chip?
  The MPU-9250 has a Digital Motion Processor (DMP), but most users perform fusion on the host MCU for better control.