sensors-demo.c

/*
 * Copyright (c) 2010, Loughborough University - Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 */

/**
 * \file
 *         Example to demonstrate-test cc2530 sensor functionality
 *
 *         B1 turns LED_GREEN on and off.
 *
 *         The node takes readings from the various sensors every x seconds and
 *         prints out the results.
 *
 *         We use floats here to translate the AD conversion results to
 *         meaningful values. However, our printf does not have %f support so
 *         we use an ugly hack to print out the value by extracting the integral
 *         part and then the fractional part. Don't try this at home.
 *
 *         Temperature:
 *           Math is correct, the sensor needs calibration per device.
 *           I currently use default values for the math which may result in
 *           very incorrect values in degrees C.
 *           See TI Design Note DN102 about the offset calibration.
 *
 *         Supply Voltage (VDD):
 *           For VDD, math is correct, conversion is correct.
 *           See DN101 for details.
 *
 *         Make sure you enable/disable things in contiki-conf.h
 *
 * \author
 *         George Oikonomou - <oikonomou@users.sourceforge.net>
 */

#include "contiki.h"
#include "contiki-conf.h"
#include "dev/leds.h"

#include "dev/button-sensor.h"
#include "dev/adc-sensor.h"

#define DEBUG 1

#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#else /* DEBUG */
/* We overwrite (read as annihilate) all output functions here */
#define PRINTF(...)
#endif /* DEBUG */
/*---------------------------------------------------------------------------*/
PROCESS(sensors_test_process, "Sensor Test Process");
#if BUTTON_SENSOR_ON
PROCESS(buttons_test_process, "Button Test Process");
AUTOSTART_PROCESSES(&sensors_test_process, &buttons_test_process);
#else
AUTOSTART_PROCESSES(&sensors_test_process);
#endif
/*---------------------------------------------------------------------------*/
#if BUTTON_SENSOR_ON
PROCESS_THREAD(buttons_test_process, ev, data)
{
  struct sensors_sensor *sensor;

  PROCESS_BEGIN();

  while (1) {

    PROCESS_WAIT_EVENT_UNTIL(ev == sensors_event);

    /* If we woke up after a sensor event, inform what happened */
    sensor = (struct sensors_sensor *)data;
    if(sensor == &button_sensor) {
      PRINTF("Button Press\n");
      leds_toggle(LEDS_GREEN);
    }
  }

  PROCESS_END();
}
#endif
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(sensors_test_process, ev, data)
{
  static struct etimer et;

  /* Sensor Values */
  static int rv;
  static struct sensors_sensor * sensor;
  static float sane = 0;
  static int dec;
  static float frac;

  PROCESS_BEGIN();

  PRINTF("========================\n");
  PRINTF("Starting Sensor Example.\n");
  PRINTF("========================\n");

  /* Set an etimer. We take sensor readings when it expires and reset it. */
  etimer_set(&et, CLOCK_SECOND * 2);

  while (1) {

    PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));

    /*
     * Request some ADC conversions
     * Return value -1 means sensor not available or turned off in conf
     */
    sensor = sensors_find(ADC_SENSOR);
    if (sensor) {
      PRINTF("------------------\n");
      leds_on(LEDS_RED);
      /*
       * Temperature:
       * Using 1.25V ref. voltage (1250mV).
       * Typical AD Output at 25°C: 1480
       * Typical Co-efficient     : 4.5 mV/°C
       *
       * Thus, at 12bit decimation (and ignoring the VDD co-efficient as well
       * as offsets due to lack of calibration):
       *
       *          AD - 1480
       * T = 25 + ---------
       *              4.5
       */
      rv = sensor->value(ADC_SENSOR_TYPE_TEMP);
      if(rv != -1) {
        sane = 25 + ((rv - 1480) / 4.5);
        dec = sane;
        frac = sane - dec;
        PRINTF("  Temp=%d.%02u C (%d)\n", dec, (unsigned int)(frac*100), rv);
      }
      /*
       * Power Supply Voltage.
       * Using 1.25V ref. voltage.
       * AD Conversion on VDD/3
       *
       * Thus, at 12bit resolution:
       *
       *          ADC x 1.25 x 3
       * Supply = -------------- V
       *               2047
       */
      rv = sensor->value(ADC_SENSOR_TYPE_VDD);
      if(rv != -1) {
        sane = rv * 3.75 / 2047;
        dec = sane;
        frac = sane - dec;
        PRINTF("Supply=%d.%02u V (%d)\n", dec, (unsigned int)(frac*100), rv);
        /* Store rv temporarily in dec so we can use it for the battery */
        dec = rv;
      }
      /*
       * Battery Voltage - ToDo
       *   rv = sensor->value(ADC_SENSOR_TYPE_BATTERY);
       */

      leds_off(LEDS_RED);
    }
    etimer_reset(&et);
  }
  PROCESS_END();
 }
/*---------------------------------------------------------------------------*/