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/**
* @file rc_test_bmp.c
* @example rc_test_bmp
*
* This serves as an example of how to read the barometer.
*
* @author James Strawson
* @date 3/14/2018
*/
#include <stdio.h>
#include <signal.h>
#include <rc/math/filter.h>
#include <rc/time.h>
#include <rc/bmp.h>
// choice of 1,2,4,8,16 oversampling. Here we use 16 and sample at 25hz which
// is close to the update rate specified in rc/bmp.h for that oversample.
#define OVERSAMPLE BMP_OVERSAMPLE_16
// choice of OFF, 2, 4, 8, 16 filter constants. Here we turn off the filter and
// opt to use our own 2nd order filter instead.
#define INTERNAL_FILTER BMP_FILTER_OFF
// our own low pass filter
#define ORDER 2
#define CUTOFF_FREQ 2.0f // 2rad/s, about 0.3hz
#define BMP_CHECK_HZ 25
#define DT 1.0f/BMP_CHECK_HZ
static int running = 0;
// interrupt handler to catch ctrl-c
static void signal_handler(__attribute__ ((unused)) int dummy)
{
running=0;
return;
}
int main()
{
rc_bmp_data_t data;
double filtered_alt;
rc_filter_t lowpass = RC_FILTER_INITIALIZER;
// set signal handler so the loop can exit cleanly
signal(SIGINT, signal_handler);
running = 1;
// create the lowpass filter
if(rc_filter_butterworth_lowpass(&lowpass,ORDER, DT, CUTOFF_FREQ)) return -1;
// init barometer and read in first data
if(rc_bmp_init(OVERSAMPLE, INTERNAL_FILTER)) return -1;
if(rc_bmp_read(&data)) return -1;
// prefill low pass filter
rc_filter_prefill_inputs(&lowpass, data.alt_m);
rc_filter_prefill_outputs(&lowpass, data.alt_m);
// print a header
printf("\n");
printf(" temp |");
printf(" pressure |");
printf(" altitude |");
printf(" filtered |");
printf("\n");
//now just wait, print_data will run
while(running){
rc_usleep(1000000/BMP_CHECK_HZ);
// perform the i2c reads to the sensor, on bad read just try later
if(rc_bmp_read(&data)) continue;
// if we got here, new data was read and is ready to be accessed.
// these are very fast function calls and don't actually use i2c
filtered_alt = rc_filter_march(&lowpass,data.alt_m);
printf("\r");
printf("%6.2lfC |", data.temp_c);
printf("%7.2lfkpa |", data.pressure_pa/1000.0);
printf("%8.2lfm |", data.alt_m);
printf("%8.2lfm |", filtered_alt);
fflush(stdout);
}
printf("\n");
rc_bmp_power_off();
return 0;
}