| 0,0 → 1,90 |
|---|
| /* |
| MS561101BA_altitude.pde - Computes altitude from sea level using pressure readings from the sensor. |
| The algorithm uses the Hypsometric formula as explained in http://keisan.casio.com/has10/SpecExec.cgi?path=06000000.Science%2F02100100.Earth%20science%2F12000300.Altitude%20from%20atmospheric%20pressure%2Fdefault.xml&charset=utf-8 |
| TODO: The results are not that good. Suggestions on improvements welcome. |
| |
| Copyright (C) 2011 Fabio Varesano <fvaresano@yahoo.it> |
| |
| Development of this code has been supported by the Department of Computer Science, |
| Universita' degli Studi di Torino, Italy within the Piemonte Project |
| http://www.piemonte.di.unito.it/ |
| |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the version 3 GNU General Public License as |
| published by the Free Software Foundation. |
| |
| This program 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/>. |
| |
| */ |
| |
| |
| //#define DEBUG_V |
| |
| #include <Wire.h> |
| //#include <DebugUtils.h> |
| #include <MS561101BA.h> |
| |
| |
| #define MOVAVG_SIZE 32 |
| |
| MS561101BA baro = MS561101BA(); |
| |
| float movavg_buff[MOVAVG_SIZE]; |
| int movavg_i=0; |
| |
| const float sea_press = 1013.25; |
| float press, temp; |
| |
| void setup() { |
| Wire.begin(); |
| Serial.begin(115200); |
| delay(1000); |
| |
| // Suppose that the CSB pin is connected to GND. |
| // You'll have to check this on your breakout schematics |
| baro.init(MS561101BA_ADDR_CSB_LOW); |
| delay(100); |
| |
| // populate movavg_buff before starting loop |
| for(int i=0; i<MOVAVG_SIZE; i++) { |
| movavg_buff[i] = baro.getPressure(MS561101BA_OSR_4096); |
| } |
| } |
| |
| void loop() { |
| Serial.print(" temp: "); |
| temp = baro.getTemperature(MS561101BA_OSR_4096); |
| Serial.print(temp); |
| Serial.print(" degC pres: "); |
| pushAvg(baro.getPressure(MS561101BA_OSR_4096)); |
| press = getAvg(movavg_buff, MOVAVG_SIZE); |
| Serial.print(press); |
| Serial.print(" mbar altitude: "); |
| Serial.print(getAltitude(press, temp)); |
| Serial.println(" m"); |
| delay(100); |
| } |
| |
| float getAltitude(float press, float temp) { |
| return ((pow((sea_press / press), 1/5.257) - 1.0) * (temp + 273.15)) / 0.0065; |
| } |
| |
| void pushAvg(float val) { |
| movavg_buff[movavg_i] = val; |
| movavg_i = (movavg_i + 1) % MOVAVG_SIZE; |
| } |
| |
| float getAvg(float * buff, int size) { |
| float sum = 0.0; |
| for(int i=0; i<size; i++) { |
| sum += buff[i]; |
| } |
| return sum / size; |
| } |