The AltIMU-10 v4 is an inertial measurement unit (IMU) and altimeter that features the same L3GD20H gyro and LSM303D accelerometer and magnetometer as the MinIMU-9 v3, and adds an LPS25H digital barometer. An I²C interface accesses ten independent pressure, rotation, acceleration, and magnetic measurements that can be used to calculate the sensor’s altitude and absolute orientation. The board operates from 2.5 to 5.5 V and has a 0.1″ pin spacing.
The AltIMU-10 v4 features a newer pressure sensor than its predecessor, the AltIMU-10 v3, enabling pressure and altitude measurements with higher accuracy and lower noise, but the two boards are otherwise identical. Compared to the original AltIMU-10, the v4 version offers a number of improvements arising from the use of newer MEMS sensors, including a wider maximum magnetic sensing range and better gyroscopic accuracy and stability. This version also adds a pin for changing the sensor slave addresses, allowing two AltIMUs to be on the same I²C bus.
The AltIMU-10 v4 is pin-compatible with both the v3 version and the original AltIMU-10, but changes in I²C addresses and configuration registers might require some changes to software written for the older version (this should not be an issue if you are using our Arduino libraries). It is also pin-compatible with the MinIMU-9 v3 and offers the same functionality augmented by a digital barometer that can be used to obtain pressure and altitude measurements. It includes a second mounting hole and is only 0.2″ longer than the MinIMU-9 v3. Any code written for the MinIMU-9 v3 should also work with the AltIMU-10 v4.
The LPS25H, L3GD20H, and LSM303D have many configurable options, including selectable resolutions for the barometer and dynamically selectable sensitivities for the gyro, accelerometer, and magnetometer. Each sensor also has a choice of output data rates. The three 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, the SA0 pin is accessible, allowing users to change the slave addresses and have two AltIMUs connected on the same I²C bus.
The nine independent rotation, acceleration, and magnetic readings provide all the data needed to make an attitude and heading reference system (AHRS), and readings from the absolute pressure sensor can be easily converted to altitudes, giving you a total of ten independent measurements (sometimes called 10DOF). With an appropriate algorithm, a microcontroller or computer can use the data to calculate the orientation and height of the AltIMU 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.
The carrier board includes a low-dropout linear voltage regulator that provides the 3.3 V required by the LPS25H, L3GD20H, and LSM303D, allowing the module to be powered from a single 2.5 V to 5.5 V supply. The regulator output is available on the VDD pin and can supply almost 150 mA to external devices. The breakout board also includes a circuit that shifts the I²C clock and data lines to the same logic voltage level as the supplied VIN, making it simple to interface the board with 5 V systems. The board’s 0.1″ pin spacing makes it easy to use with standard solderless breadboards and 0.1″ perfboards.
Note: The AltIMU-10 v4 is a compact (1.0″ × 0.5″) board that combines ST’s LPS25H digital barometer, L3GD20H 3-axis gyroscope, and LSM303D 3-axis accelerometer and 3-axis magnetometer to form an inertial measurement unit (IMU) and altimeter; we therefore recommend careful reading of the LPS25H datasheet, L3GD20H datasheet, and LSM303D datasheet before using this product. These sensors are great ICs, but their small packages make them difficult for the typical student or hobbyist to use. They also operate at voltages below 3.6 V, which can make interfacing difficult for microcontrollers operating at 5 V. The AltIMU-10 v4 addresses these issues by incorporating additional electronics, including a voltage regulator and a level-shifting circuit, while keeping the overall size as compact as possible. The board ships fully populated with its SMD components, including the L3GD20H, LSM303D, and LPS25H, as shown in the product picture.
A 1×6 strip of 0.1″ header pins and a 1×5 strip of 0.1″ right-angle header pins are included. You can solder the header strip of your choice to the board for use with custom cables or solderless breadboards or solder wires directly to the board itself for more compact installations. The board features two mounting holes that work with #2 or M2 screws (not included).
- Dimensions: 1.0″ × 0.5″ × 0.1″ (25 mm × 13 mm × 3 mm)
- Weight without header pins: 0.8 g (0.03 oz)
- Operating voltage: 2.5 V to 5.5 V
- Supply current: 6 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
- Barometer: 24-bit pressure reading (4096 LSb/mbar)
- Sensitivity range:
- Gyro: ±245, ±500, or ±2000°/s
- Accelerometer: ±2, ±4, ±6, ±8, or ±16 g
- Magnetometer: ±2, ±4, ±8, or ±12 gauss
- Barometer: 260 mbar to 1260 mbar (26 kPa to 126 kPa)
AltIMU-10 v4 schematic diagram
LPS25H Pressure/Altitude Sensor Carrier with Voltage Regulator schematic diagram
UM10204 I²C-bus specification and user manual
L3G Arduino library
This is a library for the Arduino that interfaces with the L3GD20H and L3GD20 3-axis gyro carriers as well as the gyros on the MinIMU-9 v3 and AltIMU-10 v3 (it also works with older versions of those boards, some of which used the L3G4200D and the L3GD20). It makes it simple to configure the device and read the raw gyro data.
LSM303 Arduino library
This is a library for the Arduino that interfaces with our LSM303D, LSM303DLHC, and LSM303DLM 3D compass and accelerometer carriers as well as the compass and accelerometer ICs on the MinIMU-9 v3 and AltIMU-10 v3 (it also works with older versions of those boards, some of which used the LSM303DLH and LSM303DLHC). It makes it simple to configure the device and read the raw accelerometer and magnetometer data, and it has a function for computing the tilt-compensated heading for those looking to use the LSM303 as a tilt-compensated compass.
LPS Arduino library
This is a library for the Arduino that interfaces with LPS25H and LPS331AP pressure/altitude sensor carriers as well as the pressure sensor on the AltIMU-10 v3(it also works with the original AltIMU-10). It makes it simple to read the raw pressure data from the sensor, and it provides functions to help calculate altitude based on the measured pressure.
MinIMU-9 + Arduino AHRS
This Arduino program (sketch) allows an Arduino connected to a MinIMU-9 v3 or AltIMU-10 v3 (or older versions of those boards) to function as an attitude and heading reference system, calculating estimated roll, pitch, and yaw angles from sensor readings that can be visualized with a 3D test program on a PC.
Pololu_Open_IMU by mikeshub
This customer-submitted Arduino program (sketch) is similar to MinIMU-9 + Arduino AHRS except it uses the Madgwick algorithm. It outputs pitch, yaw, and roll angles.
This Arduino program by Camel Software can read data from AltIMU-10, compute the orientation of the board, and output it over serial. It uses quaternions internally to represent the rotation, but can output Euler anglers, a rotation matrix, or a quaternion. The MinIMU-9 v2 is just an AltIMU-10 without a pressure sensor, so the code can be made to work with a MinIMU-9 v2 by commenting out a few lines.
LPS331AP pressure sensor test flight
A blog post by Pololu president Jan Malášek about testing the LPS331AP pressure sensor as an altimeter in an airplane.
RTIMULib IMU library for embedded Linux systems
RTIMULib, written by richards-tech, is a library for embedded Linux systems designed to make it easy to interface with an IMU and get Kalman-filtered orientation estimates. It works with MinIMU-9 v3, AltIMU-10 v3, and AltIMU-10 v4 (as well as the older MinIMU-9 v2 and AltIMU-10, and it includes two demo programs that aid in testing and calibrating the sensors. Instructions are provided for setting up RTIMULib on a Raspberry Pi.
Orientation sensing with the Raspberry Pi and MinIMU-9 v2
This project explains how to connect MinIMU-9 v2 (or AltIMU-10) sensor board to a Raspberry Pi and use it to sense orientation. It includes a video, wiring instructions, and code.
Using the L3GD20 gyroscope in control systems
This is a YouTube playlist by control systems lecturer Brian Douglas that uses the L3GD20 MEMS gyroscope. It describes the fundamentals of the gyro and how to use it for closed and open loop control projects with MATLAB/Simulink and Arduino.
ascii_graph by drewtm
This sketch outputs a text-based graph of LSM303 accelerometer and L3G gyro data, providing a quick way to check whether the sensors are working as expected.
MinIMU-9 v2 connected to 3ds Max in real time
A MinIMU-9 v2 is connected to an Arduino Uno to interact in real time with 3ds Max. This 3ds Max MinIMU-9 tutorial includes source code, 3ds Max files, and step-by-step instructions.
Example LSM303D Python v2 script for Raspberry Pi
This Python v2 example for the Raspberry Pi reads and prints the accelerometer and magnetometer data from the LSM303D 3D Compass and Accelerometer Carrier.