Development

Sensors / Agriculture Board:

» Ag 03: Atmospheric Pressure

In this example the Agriculture 2.0 sensor board is turned on and the pressure sensor read every second approximately, printing the result through the USB port.

Required Materials

1 x Waspmote
1 x Battery
1 x Coin cell
1 x Agriculture 2.0 board or Agriculture PRO 2.0 board
1 x Atmospheric Pressure sensor (MPX4115A)

Notes

* Remember to connect the battery to Waspmote for proper operation.
* The connection of the sensor is described in the Agriculture 2.0 technical guide.
* The output of this sensor may sometimes be noisy, in this case a software filtering will be advisable
* Remember the atmospheric pressure value obtained is absolute, it will be necessary a conversion in function of height

Code

/*  
 *  --[Ag_3] - Reading the Atmospheric Pressure sensor at Agriculture v20 board-- 
 *  
 *  Explanation: Turn on the Agriculture v20 board and read the Atmospheric
 *  Pressure sensor second
 *  
 *  Copyright (C) 2012 Libelium Comunicaciones Distribuidas S.L. 
 *  http://www.libelium.com 
 *  
 *  This program 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 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/>. 
 *  
 *  Version:           0.1 
 *  Design:            David Gascón 
 *  Implementation:    Manuel Calahorra
 */

#include <WaspSensorAgr_v20.h>

// Variable to store the read value
float value;

void setup()
{
  // Turn on the USB and print a start message
  USB.ON();
  USB.println(F("start"));
  delay(100);

  // Turn on the sensor board
  SensorAgrv20.ON();
  
  // Turn on the RTC
  RTC.ON();
  
}
 
void loop()
{
  // Part 1: Sensor reading
  // Turn on the sensor and wait for stabilization and response time
  SensorAgrv20.setSensorMode(SENS_ON, SENS_AGR_PRESSURE);
  delay(100);
  
  // Read the atmospheric pressure sensor 
  value = SensorAgrv20.readValue(SENS_AGR_PRESSURE);
  
  // Turn off the sensor
  SensorAgrv20.setSensorMode(SENS_OFF, SENS_AGR_PRESSURE);
  
  // Part 2: USB printing
  // Print the pressure value through the USB
  USB.print(F("Pressure: "));
  USB.print(value);
  USB.println(F("kPa"));
  
  delay(1000);
}

Output

B#
start
Pressure: 108.8184280395kPa
Pressure: 108.8184280395kPa
Pressure: 108.5740432739kPa
Pressure: 108.8184280395kPa

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