Development

Sensors / Smart Metering Board:

» SM 12: 10V Load Cell Reading

In this example the Smart Metering sensor board is turned on, the load cell placed on socket 9 powered at 10V, read approximately every six seconds, printing results through the USB port.

Required Materials

1 x Waspmote
1 x Battery
1 x Coin cell
1 x Smart Metering PRO board
1 x Load Cell sensor

Notes

* Remember to connect the battery to Waspmote for proper operation.
* The connection of the sensor is described in the Smart Cities technical guide.
* The conversion from volts into weight will depend on the installation of the load cell

Code

/*  
 *  --[SM_12] - Reading the Load Cell connected to the 10V socket on Smart Metering v20 board-- 
 *  
 *  Explanation: Turn on the load cell every six seconds, taking a
 *               measurement and printing its result through the USB port.
 *  
 *  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 <WaspSensorSmart_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
  SensorSmartv20.ON();
  
  // Turn on the RTC
  RTC.ON();
  
}
 
void loop()
{
  // Part 1: Sensor reading
  // Turn on the sensor and wait for stabilization and response time
  SensorSmartv20.setSensorMode(SENS_ON, SENS_SMART_LCELLS_10V);
  delay(5000);
  
  // Read the load cell
  value = SensorSmartv20.readValue(SENS_SMART_LCELLS_10V);
  
  // Turn off the sensor
  SensorSmartv20.setSensorMode(SENS_OFF, SENS_SMART_LCELLS_10V);
  
  // Part 2: USB printing
  // Print the voltage value through the USB
  USB.print(F("Voltage: "));
  USB.print(value);
  USB.println(F("V"));
  
  delay(1000);
}

Output

B#
start
Voltage: 0.0161290311V
Voltage: 0.0193548383V
Voltage: 0.4741935253V
Voltage: 0.8161289215V
Voltage: 1.4870966911V
Voltage: 1.6774192810V

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