The Pololu MinIMU-9 v5 is an inertial measurement unit (IMU) that packs an LSM6DS33 3-axis gyro and 3-axis accelerometer and an LIS3MDL 3-axis magnetometer onto a tiny 0.8" × 0.5" board. An I²C interface accesses nine independent rotation, acceleration, and magnetic measurements that can be used to calculate the sensor’s absolute orientation. The MinIMU-9 v5 board includes a voltage regulator and a level-shifting circuit that allow operation from 2.5 to 5.5 V, and the 0.1" pin spacing makes it easy to use with standard solderless breadboards and 0.1" perfboards.
Compared to the previous MinIMU-9 v3, the v5 version uses newer MEMS sensors that provide some increases in accuracy (lower noise and zero-rate offsets).
The MinIMU-9 v5 is pin-compatible with the MinIMU-9 v3, but because it uses different sensor chips, software written for older IMU versions will need to be changed to work with the v5.
The MinIMU-9 v5 is also pin-compatible with the AltIMU-10 v5, which offers the same functionality augmented by a digital barometer that can be used to obtain pressure and altitude measurements. The AltIMU includes a second mounting hole and is 0.2" longer than the MinIMU. Any code written for the MinIMU-9 v5 should also work with the AltIMU-10 v5.
The LSM6DS33 and LIS3MDL have many configurable options, including dynamically selectable sensitivities for the gyro, accelerometer, and magnetometer. Each sensor also has a choice of output data rates. The two ICs can be accessed through a shared I²C/TWI interface, allowing the sensors to be addressed individually via a single clock line and a single data line. Additionally, a slave address configuration pin allows users to change the sensors’ I²C addresses and have two MinIMUs connected on the same I²C bus.
The nine independent rotation, acceleration, and magnetic readings (sometimes called 9DOF) provide all the data needed to make an attitude and heading reference system (AHRS). With an appropriate algorithm, a microcontroller or computer can use the data to calculate the orientation of the MinIMU board. The gyro can be used to very accurately track rotation on a short timescale, while the accelerometer and compass can help compensate for gyro drift over time by providing an absolute frame of reference. The respective axes of the two chips are aligned on the board to facilitate these sensor fusion calculations.
Dimensions: 0.8" × 0.5" × 0.1" (20 mm × 13 mm × 3 mm)
Weight without header pins: 0.7 g (0.02 oz)
Operating voltage: 2.5 V to 5.5 V
Supply Current: 5 mA
Output format (I²C):
Gyro: one 16-bit reading per axis
Accelerometer: one 16-bit reading per axis
Magnetometer: one 16-bit reading per axis
Sensitivity range:
Gyro: ±125, ±245, ±500, ±1000, or ±2000°/s
Accelerometer: ±2, ±4, ±8, or ±16 g
Magnetometer: ±4, ±8, ±12, or ±16 gauss