I am trying to write code to get the acceleration values from MPU 6050, the code in arduino for this is:

#include<Wire.h>
const int MPU = 0x68;
float AccX, AccY, AccZ;

void setup() {
  Serial.begin(9600);

  Wire.begin();
  Wire.beginTransmission(MPU);
  Wire.write(0x6B);
  Wire.write(0);
  Wire.endTransmission(true);


  Wire.beginTransmission(MPU);
  Wire.write(0x1C);
  Wire.write(0b00011000);  //scale factor +/-16g
  Wire.endTransmission();
}
loop(){
  Wire.beginTransmission(MPU);
  Wire.write(0x3B);
  Wire.endTransmission(false);
  Wire.requestFrom(MPU, 14, true); // Solicita os dados ao sensor

 AccX = Wire.read() << 8 | Wire.read(); //0x3B (ACCEL_XOUT_H) & 0x3C (ACCEL_XOUT_L)
 AccY = Wire.read() << 8 | Wire.read(); //0x3D (ACCEL_YOUT_H) & 0x3E (ACCEL_YOUT_L)
 AccZ = Wire.read() << 8 | Wire.read(); //0x3F (ACCEL_ZOUT_H) & 0x40 (ACCEL_ZOUT_L)

 Serial.print(AccX / 2048);
 Serial.print(" ");
 Serial.print(AccY / 2048);
 Serial.print(" ");
 Serial.println(AccZ / 2048);
}

i have already started making the porting to toit, and i am stuck in this:

import gpio
import i2c

MPU9250_ADDRESS := 0x68
ACCEL_CONFIG_REG := 0x1C


main:
    bus := i2c.Bus
        --sda=gpio.Pin 21
        --scl=gpio.Pin 22

    device := bus.device MPU9250_ADDRESS

can any one help me to finish this code in toit?

Off-topic: prefer to indent your code with two spaces (the

bus :=

and

device :=

). This will make the syntax highlighter happier. The

--sda=

can then be intended by 4. Small warning: I haven't tested any of the code I posted here. Let me know if something doesn't seem correct or doesn't work. The first thing the code does is to set the 0x1C register. If you look at the register map (which, for some reason, is not in the data sheet) you can see that 0x1C is the ACCEL_CONFIG register (as you correctly stated with your constant): https://invensense.tdk.com/wp-content/uploads/2015/02/MPU-6000-Register-Map1.pdf (Side-note: for constants, like

MPU9250_ADDRESS

and

ACCEL_CONFIG_REG

, prefer

::=

instead of

:=

. That just means that the variables are final and can't be changed). It sets the value

0b00011000

. According to the register map, this means that AFS_SEL is set to 0b11. On page 15 (Register 28), it explains that this means that the accelerometer reads values in the whole 16g range. This means that it might be a bit less precise, but can handle stronger accelerations. You could change it to

0b00000000

for more precise measurements. In that case you will need to change the constant to go from raw value to acceleration value later in the code, though. To write to an i2c register you would use the following code:

registers := device.registers
  registers.write_u8 ACCEL_CONFIG_REG 0b00011000

Thank you very much for the detailed reply. I appreciate your advice and I will definitely test the code as well as the mpu6886 lib. If everything goes smoothly, I will reply here

nice. We should probably make an

mpu6xxx

package that knows about these differences.

I'll later posted on my github and linkedin, the project that i'm made using Toit for my thesis defense, that is a fall detection project: detecting object falls in real-time using mpu6050. really thanks for your help.

Thanks!

It appears to me that the implementation at the register level is quite similar to the one I made. To determine if the sensor is falling or not, you just need to calculate the total force it's experiencing using the formula sqrt(ax2 + ay2 +ax**2). When the sensor is falling, the total force is almost zero.

The advantage of using the sensor is that you can just wait for the interrupt. No need to continuously poll

sure