1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
|
/*
* spreadspace avr utils - usb-bmp180 example
*
*
* Copyright (C) 2016 Bernhard Tittelbach <bernhard@tittelbach.org>
* basically this is refactored and enhanced code from:
* https://github.com/sparkfun/BMP180_Breakout_Arduino_Library
* Please buy the sparkfun people Beer when you see them!!!!
*
* This file is part of spreadspace avr utils.
*
* spreadspace avr utils 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
* any later version.
*
* spreadspace avr utils 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 spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <stdio.h>
#include "util.h"
#include "led.h"
#include "usbio.h"
#include "Arduino.h"
#include "SFE_BMP180.h"
SFE_BMP180 pressure;
#define ALTITUDE 353.0 // Altitude of Graz in Austria
int main(void)
{
MCUSR &= ~(1 << WDRF);
wdt_disable();
cpu_init();
led_init();
usbio_init();
sei();
arduino_init();
if (pressure.begin())
printf("BMP180 init success");
else
{
// Oops, something went wrong, this is usually a connection problem,
// see the comments at the top of this sketch for the proper connections.
printf("BMP180 init fail\n\n");
while(1); // Pause forever.
}
for(;;) {
usbio_task();
char status;
double T,P,p0,a;
// Loop here getting pressure readings every 10 seconds.
// If you want sea-level-compensated pressure, as used in weather reports,
// you will need to know the altitude at which your measurements are taken.
// We're using a constant called ALTITUDE in this sketch:
printf("\nprovided altitude: ");
printf(ALTITUDE,0);
printf(" meters, ");
printf(ALTITUDE*3.28084,0);
printf(" feet\n");
// If you want to measure altitude, and not pressure, you will instead need
// to provide a known baseline pressure. This is shown at the end of the sketch.
// You must first get a temperature measurement to perform a pressure reading.
// Start a temperature measurement:
// If request is successful, the number of ms to wait is returned.
// If request is unsuccessful, 0 is returned.
status = pressure.startTemperature();
if (status != 0)
{
// Wait for the measurement to complete:
_delay_ms(status);
// Retrieve the completed temperature measurement:
// Note that the measurement is stored in the variable T.
// Function returns 1 if successful, 0 if failure.
status = pressure.getTemperature(T);
if (status != 0)
{
// Print out the measurement:
printf("temperature: %02d degC\n",T);
// Start a pressure measurement:
// The parameter is the oversampling setting, from 0 to 3 (highest res, longest wait).
// If request is successful, the number of ms to wait is returned.
// If request is unsuccessful, 0 is returned.
status = pressure.startPressure(3);
if (status != 0)
{
// Wait for the measurement to complete:
_delay_ms(status);
// Retrieve the completed pressure measurement:
// Note that the measurement is stored in the variable P.
// Note also that the function requires the previous temperature measurement (T).
// (If temperature is stable, you can do one temperature measurement for a number of pressure measurements.)
// Function returns 1 if successful, 0 if failure.
status = pressure.getPressure(P,T);
if (status != 0)
{
// Print out the measurement:
printf("absolute pressure: %02d mb, %02d inHg\n", P, P*0.0295333727);
// The pressure sensor returns abolute pressure, which varies with altitude.
// To remove the effects of altitude, use the sealevel function and your current altitude.
// This number is commonly used in weather reports.
// Parameters: P = absolute pressure in mb, ALTITUDE = current altitude in m.
// Result: p0 = sea-level compensated pressure in mb
p0 = pressure.sealevel(P,ALTITUDE); // we're at 1655 meters (Boulder, CO)
printf("relative (sea-level) pressure: %02d mb, %0d2 inHg", p0, p0*0.0295333727);
// On the other hand, if you want to determine your altitude from the pressure reading,
// use the altitude function along with a baseline pressure (sea-level or other).
// Parameters: P = absolute pressure in mb, p0 = baseline pressure in mb.
// Result: a = altitude in m.
a = pressure.altitude(P,p0);
printf("computed altitude: %dm\n",a);
}
else printf("error retrieving pressure measurement\n");
}
else printf("error starting pressure measurement\n");
}
else printf("error retrieving temperature measurement\n");
}
else printf("error starting temperature measurement\n");
_delay_ms(5000); // Pause for 5 seconds.
}
}
|
