【Follow me Season 2 Episode 4】 Mission 2 IMU

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【Follow me Season 2 Episode 4】 Mission 2 IMU [Copy link]

 

IMU is a common sensor in electronic devices. It is a must-have in mobile phones. For example, if you want to make the effect of spatial audio headphones, you actually need to add an IMU. The Arduino Nano RP2040 Connect board is equipped with ST's six-axis IMU (three axes of acceleration and three axes of angular velocity), which can meet the minimum direction calculation (relatively high precision must also add the three axes of geomagnetism).

Hardware Resources

ST's six-axis IMU LSM6DSOXTR is connected to the GPIO12 and GPIO13 pins of RP2040 through I2C, which means that if we want to write the driver from 0, we need to use I2C to read and write registers to read the current IMU information. In addition, the interrupt pin is also connected to GPIO24 of RP2040. This pin is used to notify 2040 that new data is ready. It is usually a pulse waveform. After receiving this pulse, the master control needs to immediately read the data from the imu and cancel the interrupt status in order to perform the next imu status detection.

Software Coding

Since Arduino has encapsulated this imu module, we do not need to implement the underlying interface. We only need to reference the corresponding header file and read and print the data according to the interface provided by the header file. The specific code is as follows:

#include <WiFiNINA.h>
#include <Arduino_LSM6DSOX.h>

float Ax, Ay, Az;
float Gx, Gy, Gz;

void setup() {
 Serial.begin(9600);
 while (!Serial);
 // IMU
 if (!IMU.begin()) {
  Serial.println("Failed to initialize IMU!");
  while (1);
 }
 Serial.print("Accelerometer sample rate = ");
 Serial.print(IMU.accelerationSampleRate());
 Serial.println("Hz");
 Serial.println();
 Serial.print("Gyroscope sample rate = "); 
 Serial.print(IMU.gyroscopeSampleRate());
 Serial.println("Hz");
 Serial.println();
}

void imuHandle() {
  bool needUpdate = 0;
  if (IMU.accelerationAvailable()) {
  IMU.readAcceleration(Ax, Ay, Az);
  needUpdate = 1;
 }
 if (IMU.gyroscopeAvailable()) {
  IMU.readGyroscope(Gx, Gy, Gz);
  needUpdate = 1;
 }
 if(needUpdate) {
  Serial.print("Ax: ");
  Serial.print(Ax);
  Serial.print(", Ay: ");
  Serial.print(Ay);
  Serial.print(", Az: ");
  Serial.print(Az);
  Serial.print(", Gx: ");
  Serial.print(Gx);
  Serial.print(", Gy: ");
  Serial.print(Gy);
  Serial.print(", Gz: ");
  Serial.print(Gz);
  Serial.println();
 }
}

void loop() {
  imuHandle();
}

Summarize

Since I don't know the data units of the Arduino package, I don't dare to convert the data into a four-element signal and finally into a right angle. This part needs further coding later.