baro_board.c File Reference

#include "subsystems/sensors/baro.h"
#include "generated/airframe.h"
#include "subsystems/abi.h"
#include "led.h"

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Macros
#define	BOOZ_ANALOG_BARO_THRESHOLD   850
	threshold >0 && <1023 More...
#define	BOOZ_BARO_SENS   0.759837
	scale factor to convert raw ADC measurement to pressure in Pascal. More...

Functions
void	baro_init (void)
void	baro_periodic (void)
void	baro_board_calibrate (void)

Variables
struct BaroBoard	baro_board

Macro Definition Documentation

BOOZ_ANALOG_BARO_THRESHOLD

#define BOOZ_ANALOG_BARO_THRESHOLD   850

threshold >0 && <1023

Definition at line 37 of file baro_board.c.

BOOZ_BARO_SENS

#define BOOZ_BARO_SENS   0.759837

scale factor to convert raw ADC measurement to pressure in Pascal.

Sensor Sensitivity -> SS = 0.045 mv / Pa Sensor Gain -> G = 94.25 Sensitivity -> S = SS*G = 4.24125 mV / Pa 10 bit ADC -> A = 3.3 V / 1024 = 3.223 mV / LSB Total Sensitivity SENS = A / S = 0.759837

For the real pressure you also need to take into account the (variable) offset

supply voltage Vs = 5V real sensor sensitivity Vout = Vs * (0.009 P - 0.095) voltage variable offset Voff(DAC) = Vs / 69.23 + (DAC * 3.3 / 1024) / 21.77 ADC voltage at init Vadc = 3.3*BARO_THRESHOLD/1024 = Vout - Voff

=> Inverting these formulas can give the 'real' pressure

since we don't care that much in this case, we can take a fixed offset of 101325 Pa

Definition at line 60 of file baro_board.c.

Function Documentation

baro_board_calibrate()

void baro_board_calibrate

(

void

)

Definition at line 95 of file baro_board.c.

References baro_board, BB_RUNNING, BOOZ_ANALOG_BARO_THRESHOLD, DACSet(), LED_ON, LED_TOGGLE, BaroBoard::offset, BaroBoard::status, and BaroBoard::value_filtered.

Referenced by baro_periodic().

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baro_init()

void baro_init

(

void

)

Definition at line 65 of file baro_board.c.

References BaroBoard::absolute, adc_buf_channel(), ADC_CHANNEL_BARO, baro_board, BB_UNINITIALIZED, BaroBoard::buf, DACSet(), DEFAULT_AV_NB_SAMPLE, LED_OFF, BaroBoard::offset, BaroBoard::status, and BaroBoard::value_filtered.

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baro_periodic()

void baro_periodic

(

void

)

Definition at line 80 of file baro_board.c.

References BaroBoard::absolute, adc_buf::av_nb_sample, baro_board, baro_board_calibrate(), BARO_BOARD_SENDER_ID, BB_UNINITIALIZED, BOOZ_ANALOG_BARO_THRESHOLD, BOOZ_BARO_SENS, BaroBoard::buf, get_sys_time_usec(), BaroBoard::status, adc_buf::sum, and BaroBoard::value_filtered.

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Variable Documentation

baro_board

struct BaroBoard baro_board

Definition at line 63 of file baro_board.c.

Referenced by baro_board_calibrate(), baro_init(), baro_periodic(), and lisa_l_baro_event().