lighting-switch.c

#include "thsq.h"
#include "ti-lib.h"
/*---------------------------------------------------------------------------*/
/*
 * Thingsquare lighting switch with slider.
 * 
 * This client uses a linear potentiometer to set the dim level of the lights
 * in the network. To save power, we only power the potentiometer when we will
 * sample it, and we only send light control if it has moved enough.
 *
 * Usage:
 * connect the potentiometer like this:
 *     potmeter   Launchpad
 *     GND        GND
 *     Vref       DIO28
 *     output     DIO29
 * compile this client and flash the Launchpad device with the potentiometer
 * invite it to the gateway in the network with the lights/lamps
 * move the slider to control the lights
 */
/*---------------------------------------------------------------------------*/
PROCESS(slider_process, "Slider Process");

void thsq_lighting_trigger_switch(int r, int g, int b);
void thsq_default_services_set_stats_interval(int seconds);
void thsq_default_services_set_period_interval(int seconds);
/*---------------------------------------------------------------------------*/
static int
get_slider(void)
{
  int ret;
  thsq_gpio_set_gpio(1);
  ret = thsq_gpio_get_adc();
  thsq_gpio_set_gpio(0);
  return ret;
}
/*---------------------------------------------------------------------------*/
static uint8_t
map_adc_to_percent(int adc)
{
  int i;
  /* ADC range [0,3000] ca, these are the steps we break at */
  static const uint16_t p_settings[] = {
    272, 544, 816, 1088, 1360, 1632, 1904, 2176, 2448,
    2850, // for linear scale 2720, but bumped up to make 100% "end of the slide"
  };
#define NUM_ELEMENTS 10 /* above array has 10 elements */

  for(i = 0; i < NUM_ELEMENTS; i++) {
    if(adc <= p_settings[i]) {
      return i * 10;
    }
  }
  return 100;
}
/*---------------------------------------------------------------------------*/
#define SLIDER_SAMPLE_PERIOD        (CLOCK_SECOND)
#define SLIDER_CHANGE_THRESHOLD     20 /* filter out noise */

PROCESS_THREAD(slider_process, ev, data)
{
  PROCESS_BEGIN();
  static int last_value;
  static int last_p_setting = -1;
  static struct etimer et;
  unsigned int diff;
  int value;

  /* take a first reading to avoid a trigger when starting */
  last_value = get_slider();

  /* periodically sample the slider */
  while(1) {
    value = get_slider();
    if(value > last_value) {
      diff = value - last_value;
    } else {
      diff = last_value - value;
    }

    if(diff >= SLIDER_CHANGE_THRESHOLD) {
      /* only act on large enough changes */
      unsigned int p = map_adc_to_percent(value);
      if(p != last_p_setting) {
        last_p_setting = p;
        thsq_lighting_trigger_switch(p, p, p);
        
        /* notify backend on change */
        thsq_sset_printf("slider", "%d", value);
        thsq_push();
      }
    }

    last_value = value;
    etimer_set(&et, SLIDER_SAMPLE_PERIOD);
    PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
  }
  PROCESS_END();
}
/*---------------------------------------------------------------------------*/
void
app(void)
{
  /* default power mode and settings */
  thsq_set_default_mode("deadleaf");
  thsq_default_services_set_stats_interval(2*60*60); /* 2 h */
  thsq_default_services_set_period_interval(2*60*60); /* 2 h */
  thsq_dset("deadleaf", 30*60); /* 30 min poll interval */

  /* Initialize the lighting module */
  thsq_lighting_init();

  /* Initialize GPIO module */
  thsq_gpio_init();
  thsq_gpio_set_default("2829----N"); /* power pin out 28, adc in 29 */
  thsq_gpio_push_adc_periodically(0); /* don't send the ADC value to server */

  process_start(&slider_process, NULL);
}
/*---------------------------------------------------------------------------*/