ardupilot/ArduPlane/sensors.pde

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-

static void init_barometer(void)
{
    barometer.calibrate(mavlink_delay);
    ahrs.set_barometer(&barometer);
    gcs_send_text_P(SEVERITY_LOW, PSTR("barometer calibration complete"));
}

// filter altitude from the barometer with a 0.3 low pass
// filter
static LowPassFilterInt32 altitude_filter(0.3);

// read the barometer and return the updated altitude in centimeters
// above the calibration altitude
static int32_t read_barometer(void)
{
	barometer.read();
    return altitude_filter.apply(barometer.get_altitude() * 100.0);
}

// in M/S * 100
static void read_airspeed(void)
{
    airspeed.read();
	calc_airspeed_errors();
}

static void zero_airspeed(void)
{
    airspeed.calibrate(mavlink_delay);
    gcs_send_text_P(SEVERITY_LOW,PSTR("zero airspeed calibrated"));
}

static void read_battery(void)
{
	if(g.battery_monitoring == 0) {
		battery_voltage1 = 0;
		return;
	}
	
	if(g.battery_monitoring == 3 || g.battery_monitoring == 4) {
        static AP_AnalogSource_Arduino bat_pin(BATTERY_PIN_1);
		battery_voltage1 = BATTERY_VOLTAGE(bat_pin.read_average());
    }
	if(g.battery_monitoring == 4) {
        static AP_AnalogSource_Arduino current_pin(CURRENT_PIN_1);
		current_amps1	 = CURRENT_AMPS(current_pin.read_average());
		current_total1	 += current_amps1 * (float)delta_ms_medium_loop * 0.0002778;				// .0002778 is 1/3600 (conversion to hours)
	}
	
	#if BATTERY_EVENT == ENABLED
		if(battery_voltage1 < LOW_VOLTAGE)	low_battery_event();
		if(g.battery_monitoring == 4 && current_total1 > g.pack_capacity)	low_battery_event();
	#endif
}