ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_MaxsonarSeri...

63 lines
1.8 KiB
C++

/*
* Copyright (C) 2016 Intel Corporation. All rights reserved.
*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "AP_RangeFinder_MaxsonarSerialLV.h"
#include <AP_HAL/AP_HAL.h>
#include <ctype.h>
#define MAXSONAR_SERIAL_LV_BAUD_RATE 9600
extern const AP_HAL::HAL& hal;
// read - return last value measured by sensor
bool AP_RangeFinder_MaxsonarSerialLV::get_reading(float &reading_m)
{
if (uart == nullptr) {
return false;
}
int32_t sum = 0;
int16_t nbytes = uart->available();
uint16_t count = 0;
while (nbytes-- > 0) {
char c = uart->read();
if (c == '\r') {
linebuf[linebuf_len] = 0;
sum += (int)atoi(linebuf);
count++;
linebuf_len = 0;
} else if (isdigit(c)) {
linebuf[linebuf_len++] = c;
if (linebuf_len == sizeof(linebuf)) {
// too long, discard the line
linebuf_len = 0;
}
}
}
if (count == 0) {
return false;
}
// This sonar gives the metrics in inches, so we have to transform this to meters
reading_m = (2.54f * 0.01f) * (float(sum) / count);
return true;
}