sensor-imu

C library to interact with various IMUs (MPU6000, MPU6050, MPU6500, ICM20600, ICM20601, ICM2062). It was written for the raspberry-imu-viewer project, an orientation viewer in 3D for the Raspberry Pi, where you can also find a working example on how to use this library.

Features:

• works with Raspberry Pi / Linux and probably with almost every single-board computer equipped with I2C
• IMU model and address are autodetected during initialization
• sampling rate can reach 1khz (when I2C speed is 400khz)
• orientation estimation algorithms are available in folder /orientation

Installation

1. On the Raspberry Pi, enable I2C and set speed to 400khz: edit /boot/config.txt and add:

   dtparam=i2c_arm=on
   dtparam=i2c_arm_baudrate=400000
   

   then edit /etc/modules and add

   i2c-dev
   

   then reboot the system.

2. Install the dependencies:

   sudo apt install -y git make gcc libc6-dev libi2c-dev
   

3. Clone this repository:

   git clone https://github.com/aler9/sensor-imu
   

4. Create a sample source file named main.c:

   #include <stdio.h>
   #include <stdlib.h>
   
   #include "sensor-imu/imu.h"
   
   int main() {
       imut *imu;
       error *err = imu_init(&imu, "/dev/i2c-1", IMU_ACC_RANGE_2G, IMU_GYRO_RANGE_250DPS);
       if(err != NULL) {
           printf("ERR: %s\n", err);
           return -1;
       }
   
       imu_output io;
       err = imu_read(imu, &io);
       if(err != NULL) {
           printf("ERR: %s\n", err);
           return -1;
       }
   
       printf("gyro x,y,z: %f, %f, %f\n", io.gyro.x, io.gyro.y, io.gyro.z);
       printf("acc x,y,z: %f, %f, %f\n", io.acc.x, io.acc.y, io.acc.z);
       return 0;
   }

5. Build:

   gcc -o main sensor-imu/*.c main.c
   

6. Launch:

   ./main
   

API Documentation

error *imu_init(imut **pobj, const char *path, imu_acc_range acc_range, imu_gyro_range gyro_range)

Creates an IMU reader. Arguments a pointer to an empty imut* object, the path to the I2C device, the accelerometer range and the gyroscope range. It returns NULL in case of success, otherwise returns an error.

void imu_destroy(imut *obj)

Destroys an IMU reader.

error *imu_read(imut *obj, imu_output *out)

Performs a measurement. Returns an imu_output that contains the measurements.

Accelerometer measurements are expressed in [g], while gyroscope measurements are expressed in [deg/s]

Links

• https://github.com/aler9/raspberry-imu-viewer