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Attiny3216 6-axis accelerometer+gyroscope

Materials

Component

3216_6axis.jpg

Pin map

PORT PIN Arduino AMS1177(5>3.3 Step down) GY521 Memo
VCC VIN(+5V) +5V: 6-pin FTDI-Serial, 3pin UPDI programmer
GND GND GND Ground: 6-pin FTDI-Serial, 3pin UPDI programmer
VOUT(3.3V) VCC(3.3V)
PB0 SCL SCL
PB1 SDA SDA
PB2 (7, TXD) 6-pin FTDI-Serial
PB3 (6, RXD) 6-pin FTDI-Serial
PA0 (17, UPDI) 3pin UPDI programmer

Source code

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#include <Wire.h>

// MPU-6050 Address, register
#define MPU6050_WHO_AM_I     0x75  // Read Only
#define MPU6050_PWR_MGMT_1   0x6B  // Read and Write
#define MPU_ADDRESS  0x68

// I2C Initialization 
void setup() {
  Wire.begin();

  Serial.begin(115200);

  // Read at the first time
  Wire.beginTransmission(MPU_ADDRESS);
  Wire.write(MPU6050_WHO_AM_I);  //MPU6050_PWR_MGMT_1
  Wire.write(0x00);
  Wire.endTransmission();

  Wire.beginTransmission(MPU_ADDRESS);
  Wire.write(MPU6050_PWR_MGMT_1);  //MPU6050_PWR_MGMT_1 register
  Wire.write(0x00);
  Wire.endTransmission();
}


void loop() {
  Wire.beginTransmission(0x68);
  Wire.write(0x3B);
  Wire.endTransmission(false);
  Wire.requestFrom(0x68, 14, true);
  while (Wire.available() < 14);
  int16_t axRaw, ayRaw, azRaw, gxRaw, gyRaw, gzRaw, Temperature;

  axRaw = Wire.read() << 8 | Wire.read();
  ayRaw = Wire.read() << 8 | Wire.read();
  azRaw = Wire.read() << 8 | Wire.read();
  Temperature = Wire.read() << 8 | Wire.read();
  gxRaw = Wire.read() << 8 | Wire.read();
  gyRaw = Wire.read() << 8 | Wire.read();
  gzRaw = Wire.read() << 8 | Wire.read();

  // Convert the acceleration value to acceleration (G) by dividing it by the resolution
  float acc_x = axRaw / 16384.0;  //FS_SEL_0 16,384 LSB / g
  float acc_y = ayRaw / 16384.0;
  float acc_z = azRaw / 16384.0;

  // Convert angular velocity value to angular rate (degrees per sec) by dividing it by resolution.
  float gyro_x = gxRaw / 131.0;//FS_SEL_0 131 LSB / (°/s)
  float gyro_y = gyRaw / 131.0;
  float gyro_z = gzRaw / 131.0;

  Serial.print("a_X: ");  Serial.print(acc_x);
  Serial.print("| a_Y: ");  Serial.print(acc_y);
  Serial.print("| a_Z: ");  Serial.print(acc_z);
  Serial.print("| g_X: ");  Serial.print(gyro_x);
  Serial.print("| g_Y: ");  Serial.print(gyro_y);
  Serial.print("| g_Z: ");  Serial.print(gyro_z); Serial.println("");
  delay(250);
}

Serial monitor result - tilt x axis: 

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a_X: -0.07| a_Y: 0.21| a_Z: 1.06| g_X: 10.83| g_Y: 40.21| g_Z: 42.64
a_X: 0.23| a_Y: 0.06| a_Z: 1.03| g_X: -5.82| g_Y: -202.69| g_Z: -22.91
a_X: 1.42| a_Y: 0.24| a_Z: 0.00| g_X: 16.92| g_Y: -91.81| g_Z: 75.99
a_X: 0.65| a_Y: 0.04| a_Z: -0.40| g_X: 16.58| g_Y: -250.14| g_Z: 91.08
a_X: 0.81| a_Y: 0.05| a_Z: -0.76| g_X: -39.05| g_Y: 250.13| g_Z: -114.60
a_X: 0.44| a_Y: 0.09| a_Z: 0.49| g_X: 6.44| g_Y: 9.58| g_Z: 37.79
a_X: 0.69| a_Y: -0.53| a_Z: 0.28| g_X: -114.76| g_Y: -21.26| g_Z: 227.22
a_X: 0.49| a_Y: -0.98| a_Z: 0.20| g_X: -109.78| g_Y: 7.98| g_Z: 100.63
a_X: 0.54| a_Y: -1.21| a_Z: -0.14| g_X: -22.50| g_Y: 10.28| g_Z: -250.14
a_X: 1.31| a_Y: 0.24| a_Z: 0.28| g_X: 81.44| g_Y: 14.50| g_Z: -250.14
...

Consideration

Warning

  • GY521 might work by +5V VCC by some instruction.
  • GY521 module for this experiment is not stable. When power plug-in Attiny3216 breakout board, Serial value shows zero. After Plug-off and plug-in FTDI cable several times, Serial monitor shows the sensor value.

Outcome as of 2021.04.15

Reference

Last update: April 15, 2021