Important NoteThis entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!
Pololu MinIMU-9 v3
9-DOF inertial measurement unit (IMU) combining L3GD20H 3-axis gyroscope and LSM303D 3-axis accelerometer and 3-axis magnetometer on a compact 0.8″ × 0.5″ board.
Overview
The Pololu MinIMU-9 v3 is a compact inertial measurement unit that combines ST’s L3GD20H 3-axis gyroscope and LSM303D 3-axis accelerometer and 3-axis magnetometer to provide 9 degrees of freedom (9DOF) motion sensing. The board includes voltage regulation and level shifting to make it easy to interface with microcontrollers operating from 2.5V to 5.5V.
Note: This product has been discontinued and replaced by the MinIMU-9 v5, but is still available by special order.
Key Features
9-DOF Motion Sensing
- 3-axis gyroscope (L3GD20H) for rotation rate measurement
- 3-axis accelerometer (LSM303D) for linear acceleration measurement
- 3-axis magnetometer (LSM303D) for magnetic field measurement
- Sensor fusion capability for attitude and heading reference system (AHRS)
- Aligned axes for simplified sensor fusion calculations
Easy Integration
- Voltage regulation allows 2.5V to 5.5V operation
- Level shifting for I²C communication at VIN voltage level
- I²C interface with configurable slave addresses
- 0.1″ pin spacing compatible with breadboards and perfboards
- Compact size at only 0.8″ × 0.5″
Technical Specifications
Electrical Characteristics
- Operating Voltage: 2.5V to 5.5V
- Supply Current: 6mA typical
- Logic Levels: VIN voltage level (2.5V to 5.5V)
- Interface: I²C (up to 400kHz fast mode)
- Regulated Output: 3.3V at up to 150mA (VDD pin)
Physical Specifications
- Dimensions: 0.8″ × 0.5″ × 0.1″ (20mm × 13mm × 3mm)
- Weight: 0.7g (0.02oz) without header pins
- Mounting: Two mounting holes for #2 or M2 screws
- Headers: 0.1″ pin spacing, includes straight and right-angle headers
Sensor Specifications
L3GD20H Gyroscope
- Measurement Range: ±245, ±500, or ±2000°/s (selectable)
- Output Resolution: 16-bit per axis
- Operating Temperature: -40°C to +85°C
- Zero-rate level: ±10°/s
- Sensitivity: Up to 8.75 mdps/LSB
LSM303D Accelerometer
- Measurement Range: ±2, ±4, ±6, ±8, or ±16g (selectable)
- Output Resolution: 16-bit per axis
- Operating Temperature: -40°C to +85°C
- Zero-g level: ±40mg
- Sensitivity: Up to 0.061 mg/LSB
LSM303D Magnetometer
- Measurement Range: ±2, ±4, ±8, or ±12 gauss (selectable)
- Output Resolution: 16-bit per axis
- Operating Temperature: -40°C to +85°C
- Sensitivity: Up to 0.080 mgauss/LSB
Pinout and Connections
Pin Configuration
| Pin | Description |
|---|---|
| SCL | I²C clock line (level-shifted to VIN) |
| SDA | I²C data line (level-shifted to VIN) |
| GND | Ground connection |
| VIN | Main power supply (2.5V to 5.5V) |
| VDD | 3.3V regulated output (up to 150mA) |
| SA0 | I²C address selection (3.3V logic level) |
Connection Notes
- VIN: Connect to main power supply (2.5V to 5.5V)
- GND: Connect to system ground
- SCL/SDA: Connect to I²C bus at VIN voltage level
- VDD: 3.3V output for external components (optional)
- SA0: Pull low to change I²C slave addresses (default high)
I²C Addresses
| Sensor | Default Address | SA0 Low Address |
|---|---|---|
| L3GD20H (Gyro) | 0x6B (1101011b) | 0x6A (1101010b) |
| LSM303D (Accel/Mag) | 0x1D (0011101b) | 0x1E (0011110b) |
Applications
Robotics and Automation
- Robot orientation sensing for balance and navigation
- Drone flight control and stabilization systems
- Autonomous vehicle attitude determination
- Robotic arm position and movement tracking
- Mobile robot dead reckoning and localization
Motion Tracking
- Human motion capture for sports and rehabilitation
- Gaming controllers with motion input
- Virtual reality head tracking systems
- Gesture recognition interfaces
- Activity monitoring devices
Navigation Systems
- Attitude and heading reference systems (AHRS)
- Inertial navigation systems (INS)
- GPS-aided navigation with inertial backup
- Marine navigation for boats and ships
- Aircraft attitude indicators
Industrial Applications
- Machine vibration monitoring and analysis
- Platform stabilization systems
- Tilt and orientation monitoring
- Equipment positioning feedback
- Safety systems for machinery
Programming and Integration
Arduino Library Support
Pololu provides Arduino libraries for easy integration:
- L3G Arduino Library: For L3GD20H gyroscope
- LSM303 Arduino Library: For LSM303D accelerometer/magnetometer
- MinIMU-9 AHRS: Complete attitude estimation system
Basic Arduino Example
#include <Wire.h>
#include <L3G.h>
#include <LSM303.h>
L3G gyro;
LSM303 compass;
void setup() {
Serial.begin(9600);
Wire.begin();
if (!gyro.init()) {
Serial.println("Failed to detect gyro");
while (1);
}
if (!compass.init()) {
Serial.println("Failed to detect compass");
while (1);
}
gyro.enableDefault();
compass.enableDefault();
}
void loop() {
gyro.read();
compass.read();
Serial.print("G: ");
Serial.print(gyro.g.x); Serial.print(" ");
Serial.print(gyro.g.y); Serial.print(" ");
Serial.print(gyro.g.z); Serial.print(" ");
Serial.print("A: ");
Serial.print(compass.a.x); Serial.print(" ");
Serial.print(compass.a.y); Serial.print(" ");
Serial.print(compass.a.z); Serial.print(" ");
Serial.print("M: ");
Serial.print(compass.m.x); Serial.print(" ");
Serial.print(compass.m.y); Serial.print(" ");
Serial.print(compass.m.z);
Serial.println();
delay(100);
}AHRS Implementation
The MinIMU-9 v3 can be used to create a complete attitude and heading reference system:
- Roll, pitch, yaw angle calculation
- Quaternion representation for smooth rotation
- Sensor fusion algorithms (Kalman filter, complementary filter)
- Calibration procedures for accurate measurements
Calibration and Setup
Gyroscope Calibration
- Zero-rate calibration: Measure gyro output when stationary
- Temperature compensation: Account for temperature drift
- Scale factor calibration: Verify sensitivity settings
- Bias stability: Monitor long-term drift characteristics
Accelerometer Calibration
- Six-position calibration: Measure in all orientations
- Offset correction: Remove zero-g bias errors
- Scale factor correction: Normalize sensitivity
- Cross-axis sensitivity: Compensate for coupling effects
Magnetometer Calibration
- Hard iron calibration: Remove constant magnetic offsets
- Soft iron calibration: Correct for magnetic distortion
- Magnetic declination: Account for local magnetic variation
- Environmental mapping: Identify magnetic interference sources
Design Considerations
Power Supply Design
- Stable voltage: Use regulated power supply for best performance
- Decoupling: Add capacitors near power pins
- Current capability: Ensure supply can provide 6mA minimum
- Noise filtering: Filter switching noise from power supplies
Mechanical Mounting
- Rigid mounting: Minimize vibration and mechanical stress
- Axis alignment: Align sensor axes with vehicle/robot axes
- Thermal isolation: Protect from temperature extremes
- Shock protection: Use damping for high-shock environments
Signal Processing
- Digital filtering: Apply low-pass filters to reduce noise
- Sensor fusion: Combine multiple sensors for best accuracy
- Coordinate transforms: Convert between sensor and body frames
- Real-time processing: Implement efficient algorithms for real-time use
Troubleshooting
Common Issues
- No I²C communication: Check wiring and pull-up resistors
- Incorrect readings: Verify sensor orientation and calibration
- Drift problems: Implement proper calibration and filtering
- Power issues: Check voltage levels and current consumption
Performance Optimization
- Proper calibration: Follow calibration procedures carefully
- Environmental control: Minimize temperature and vibration
- Software filtering: Implement appropriate digital filters
- Regular recalibration: Update calibration parameters periodically
Included Components
- MinIMU-9 v3 board with sensors and electronics
- 1×6 straight header pins (0.1″ spacing)
- 1×5 right-angle header pins (0.1″ spacing)
- Documentation and example code links
Storage Information
- Location: Cabinet 3, Bin 28
- Quantity: 1 unit
- Condition: New, unused
- Packaging: Anti-static packaging with headers
- Status: Discontinued product, special order only