DHOB (IU5SGN)

mercoledì 23 gennaio 2019

Wakeup Arduino Uno con interrupt da MPU6050

L'accelerometro MPU6050 (altrimenti conosciuto come Gy-521) ha un pin interrupt che puo' essere programmato per risvegliare una Arduino Uno
Ho semplificato un po' il codice ritrovato a questo link

si possono personalizzare le soglie di attivazione dell'interrupt modificando il valore di MOT_THR e MOT_DUR

-----------------------------------------------------------------------
#include <avr/sleep.h>
#include <Wire.h>

#define SIGNAL_PATH_RESET 0x68
#define I2C_SLV0_ADDR 0x37
#define ACCEL_CONFIG 0x1C
#define MOT_THR 0x1F // Motion detection threshold bits [7:0]
#define MOT_DUR 0x20 // Duration counter threshold for motion interrupt generation, 1 kHz rate, LSB = 1 ms
#define MOT_DETECT_CTRL 0x69
#define INT_ENABLE 0x38
#define WHO_AM_I_MPU6050 0x75 // Should return 0x68
#define INT_STATUS 0x3A
//when nothing connected to AD0 than address is 0x68
#define ADO 0
#if ADO
#define MPU6050_ADDRESS 0x69 // Device address when ADO = 1
#else
#define MPU6050_ADDRESS 0x68 // Device address when ADO = 0
#endif

int wakePin = 2; // pin used for waking up

void wakeUpNow()
{
}

void writeByte(uint8_t address, uint8_t subAddress, uint8_t data)
{
Wire.begin();
Wire.beginTransmission(address); // Initialize the Tx buffer
Wire.write(subAddress); // Put slave register address in Tx buffer
Wire.write(data); // Put data in Tx buffer
Wire.endTransmission(); // Send the Tx buffer
}

uint8_t readByte(uint8_t address, uint8_t subAddress)
{
uint8_t data; // `data` will store the register data
Wire.beginTransmission(address); // Initialize the Tx buffer
Wire.write(subAddress); // Put slave register address in Tx buffer
Wire.endTransmission(false); // Send the Tx buffer, but send a restart to keep connection alive
Wire.requestFrom(address, (uint8_t) 1); // Read one byte from slave register address
data = Wire.read(); // Fill Rx buffer with result
return data; // Return data read from slave register
}

void setup()
{
Serial.begin(9600);
writeByte( MPU6050_ADDRESS, 0x6B, 0x00);
writeByte( MPU6050_ADDRESS, SIGNAL_PATH_RESET, 0x07);//Reset all internal signal paths in the MPU-6050 by writing 0x07 to register 0x68;
writeByte( MPU6050_ADDRESS, I2C_SLV0_ADDR, 0x20);//write register 0x37 to select how to use the interrupt pin. For an active high, push-pull signal that stays until register (decimal) 58 is read, write 0x20.
writeByte( MPU6050_ADDRESS, ACCEL_CONFIG, 0x01);//Write register 28 (==0x1C) to set the Digital High Pass Filter, bits 3:0. For example set it to 0x01 for 5Hz. (These 3 bits are grey in the data sheet, but they are used! Leaving them 0 means the filter always outputs 0.)
writeByte( MPU6050_ADDRESS, MOT_THR, 20); //Write the desired Motion threshold to register 0x1F (For example, write decimal 20).
writeByte( MPU6050_ADDRESS, MOT_DUR, 40 ); //Set motion detect duration to 1 ms; LSB is 1 ms @ 1 kHz rate
writeByte( MPU6050_ADDRESS, MOT_DETECT_CTRL, 0x15); //to register 0x69, write the motion detection decrement and a few other settings (for example write 0x15 to set both free-fall and motion decrements to 1 and accelerometer start-up delay to 5ms total by adding 1ms. )
writeByte( MPU6050_ADDRESS, INT_ENABLE, 0x40 ); //write register 0x38, bit 6 (0x40), to enable motion detection interrupt.
writeByte( MPU6050_ADDRESS, 0x37, 160 ); // now INT pin is active low

pinMode(2, INPUT); // sets the digital pin 7 as input
pinMode(wakePin, INPUT_PULLUP); // wakePin is pin no. 2
}

void sleepNow()
{
set_sleep_mode(SLEEP_MODE_PWR_DOWN);
sleep_enable();
delay(500);
attachInterrupt(0,wakeUpNow, LOW);
delay(500);
sleep_mode();

//ritorno da interrupt
delay(500);

sleep_disable();
delay(500);
detachInterrupt(0);

}

uint16_t readdata;
void loop()
{
sleepNow();
/*readdata = readByte(MPU6050_ADDRESS,0x3A);
Serial.print(readdata);Serial.print("-");
readdata = readByte(MPU6050_ADDRESS,0x37);
Serial.println(readdata);*/
  Serial.println("Movimento registrato");

}