path: root/src/sensor.cpp

#include "sensor.hpp"
#include "math.h"
#include "sensor_registers.hpp"
#include "time_utils.hpp"

Sensor::Sensor(uint8_t address, TwoWire *wire, unsigned int throttle_time) : _last_time(0)
{
	_address = address;
	_wire = wire;

	// Set default values
	accel_cal_x = 0;
	accel_cal_y = 0;
	accel_cal_z = 0;

	gyro_cal_x = 0;
	gyro_cal_y = 0;
	gyro_cal_z = 0;

	_throttle_enabled = true;
	_throttle_time = throttle_time;

	_status = SensorStatus::OK;

	_accel_sensitivity = 0;
	_accel_to_g_force = 1.0 / 16384.0;

	_gyro_sensitivity = 0;
	_ang_rate_to_dps = 1.0 / 131.0;

	// Reset the sensor
	reset();
}

bool Sensor::begin()
{
	_wire->begin();

	if (isConnected())
	{
		_wire->beginTransmission(_address);
		_wire->write(SensorRegisters::PWR_MGMT_1);
		_wire->write(SENSOR_WAKEUP);

		return (_wire->endTransmission() == 0);
	}

	return false;
}

bool Sensor::isConnected()
{
	_wire->beginTransmission(_address);
	return (_wire->endTransmission() == 0);
}

void Sensor::reset()
{
	_accel_raw_x = 0;
	_accel_raw_y = 0;
	_accel_raw_z = 0;

	_gyro_raw_x = 0;
	_gyro_raw_y = 0;
	_gyro_raw_z = 0;

	_accel_x = 0;
	_accel_y = 0;

	_pitch = 0;
	_roll = 0;
	_yaw = 0;
}

bool Sensor::read()
{
	Time now = time_now();

	if (_throttle_enabled && now.diff(_last_time).millisecs() < _throttle_time)
	{
		_status = SensorStatus::THROTTLED;
		return false;
	}

	_wire->beginTransmission(_address);
	_wire->write(SensorRegisters::ACCEL_XOUT_H);

	if (_wire->endTransmission() != 0)
	{
		_status = SensorStatus::ERR_WRITE;
		return false;
	}

	int8_t response_length = _wire->requestFrom(_address, (uint8_t)14);

	if (response_length != 14)
	{
		_status = SensorStatus::ERR_READ;
		return false;
	}

	// Accelerometer
	_accel_raw_x = _readTwoBytes(); // ACCEL_XOUT_H  ACCEL_XOUT_L
	_accel_raw_y = _readTwoBytes(); // ACCEL_YOUT_H  ACCEL_YOUT_L
	_accel_raw_z = _readTwoBytes(); // ACCEL_ZOUT_H  ACCEL_ZOUT_L

	// Gyroscope
	_gyro_raw_x = _readTwoBytes(); // GYRO_XOUT_H   GYRO_XOUT_L
	_gyro_raw_y = _readTwoBytes(); // GYRO_YOUT_H   GYRO_YOUT_L
	_gyro_raw_z = _readTwoBytes(); // GYRO_ZOUT_H   GYRO_ZOUT_L

	// Duration interval
	now.update();
	float duration = now.diff(_last_time).secs();
	_last_time = now;

	// Convert raw acceleration to g:s (g-force)
	_accel_raw_x *= _accel_to_g_force;
	_accel_raw_y *= _accel_to_g_force;
	_accel_raw_z *= _accel_to_g_force;

	// Error correct raw acceleration
	_accel_raw_x += accel_cal_x;
	_accel_raw_y += accel_cal_y;
	_accel_raw_z += accel_cal_z;

	// Prepare for Pitch Roll Yaw
	float accel_x_pow_two = pow(_accel_raw_x, 2);
	float accel_y_pow_two = pow(_accel_raw_y, 2);
	float accel_z_pow_two = pow(_accel_raw_z, 2);

	_accel_x =
		atan(_accel_raw_y / sqrt(accel_x_pow_two + accel_z_pow_two)) * RAD_TO_DEGREES;

	_accel_y = atan(-1.0 * _accel_raw_x / sqrt(accel_y_pow_two + accel_z_pow_two)) *
			   RAD_TO_DEGREES;

	// Convert raw Gyro to degrees/s
	_gyro_raw_x *= _ang_rate_to_dps;
	_gyro_raw_y *= _ang_rate_to_dps;
	_gyro_raw_z *= _ang_rate_to_dps;

	// Error correct raw gyro measurements.
	_gyro_raw_x += gyro_cal_x;
	_gyro_raw_y += gyro_cal_y;
	_gyro_raw_z += gyro_cal_z;

	_gyro_x += _gyro_raw_x * duration;
	_gyro_y += _gyro_raw_y * duration;
	_gyro_z += _gyro_raw_z * duration;

	_yaw = _gyro_z;
	_pitch = 0.96 * _gyro_y + 0.04 * _accel_y;
	_roll = 0.96 * _gyro_x + 0.04 * _accel_x;

	return true;
}

bool Sensor::setAccelSensitivity(uint8_t sensitivity)
{
	_accel_sensitivity = sensitivity;

	if (_accel_sensitivity > 3)
		_accel_sensitivity = 3;

	uint8_t val = getRegister(SensorRegisters::ACCEL_CONFIG);

	if (_status != SensorStatus::OK)
	{
		return false;
	}

	// No need to write same value
	if (((val >> 3) & 3) != _accel_sensitivity)
	{
		val &= 0xE7;
		val |= (_accel_sensitivity << 3);

		if (!setRegister(SensorRegisters::ACCEL_CONFIG, val))
		{
			return false;
		}
	}

	// Calculate conversion factor.
	_accel_to_g_force = (1 << _accel_sensitivity) * RAW_TO_G_FACTOR;

	return true;
}

bool Sensor::setGyroSensitivity(uint8_t sensitivity)
{
	_gyro_sensitivity = sensitivity;

	if (_gyro_sensitivity > 3)
		_gyro_sensitivity = 3;

	uint8_t val = getRegister(SensorRegisters::GYRO_CONFIG);

	if (_status != SensorStatus::OK)
	{
		return false;
	}

	// No need to write same value
	if (((val >> 3) & 3) != _gyro_sensitivity)
	{
		val &= 0xE7;
		val |= (_gyro_sensitivity << 3);

		if (!setRegister(SensorRegisters::GYRO_CONFIG, val))
		{
			return false;
		}
	}

	_ang_rate_to_dps = (1 << _gyro_sensitivity) * RAW_TO_DPS_FACTOR;

	return true;
}

float Sensor::getAccelX()
{
	return _accel_raw_x;
};

float Sensor::getAccelY()
{
	return _accel_raw_y;
};

float Sensor::getAccelZ()
{
	return _accel_raw_z;
};

float Sensor::getAngleX()
{
	return _accel_x;
};

float Sensor::getAngleY()
{
	return _accel_y;
};

float Sensor::getGyroX()
{
	return _gyro_raw_x;
};

float Sensor::getGyroY()
{
	return _gyro_raw_y;
};

float Sensor::getGyroZ()
{
	return _gyro_raw_z;
};

float Sensor::getPitch()
{
	return _pitch;
};

float Sensor::getRoll()
{
	return _roll;
};

bool Sensor::setRegister(uint8_t reg, uint8_t value)
{
	_wire->beginTransmission(_address);
	_wire->write(reg);
	_wire->write(value);

	if (_wire->endTransmission() != 0)
	{
		_status = SensorStatus::ERR_WRITE;
		return false;
	}

	return true;
}

uint8_t Sensor::getRegister(uint8_t reg)
{
	_wire->beginTransmission(_address);
	_wire->write(reg);

	if (_wire->endTransmission() != 0)
	{
		_status = SensorStatus::ERR_WRITE;
		return 0;
	}

	uint8_t response_length = _wire->requestFrom(_address, (uint8_t)1);
	if (response_length != 1)
	{
		_status = SensorStatus::ERR_READ;
		return 0;
	}

	uint8_t val = _wire->read();

	return val;
}

SensorStatus Sensor::getStatus()
{
	SensorStatus status = _status;
	_status = SensorStatus::OK;

	return status;
};

int16_t Sensor::_readTwoBytes()
{
	int16_t response = _wire->read();
	response <<= 8;
	response |= _wire->read();

	return response;
}