void application_start( )
{
/* Initialise the WICED device */
wiced_init();
while ( 1 )
{
WPRINT_APP_INFO( ( "Analog input voltage measurement:\n" ) );
for(uint8_t i=0; i<8; i++)
{
wiced_adc_init( analog_channel[i], 480 );
// This function only takes sample for the channel that selected by the last time invoking wiced_adc_init().
// So if you change to take sample for another channel, you need to invoke wiced_adc_init() to select this channel first.
wiced_adc_take_sample( analog_channel[i], &analog_value[i] );
WPRINT_APP_INFO( ( "Channel %d input voltage: %d\n", i, analog_value[i] ) );
}
wiced_rtos_delay_milliseconds( 3000 );
WPRINT_APP_INFO( ( "\n\n" ) );
}
}
wiced_result_t thermistor_take_sample(wiced_adc_t adc, uint16_t* sample_value)
{
wiced_result_t result = wiced_adc_take_sample(adc, sample_value);
/* Thermistor is Murata NCP18XH103J03RB (Digi-key 490-2436-1-ND )
*
* Part Number details:
* NC : NTC Chip Thermistor
* P : Plated termination
* 18 : Size 0603
* XH : Temperature Characteristics : Nominal B-Constant 3350-3399K
* 103 : Resistance 10k
* J : Tolerance +/- 5%
* 03 : Individual Specs: Standard
* RB : Paper Tape 4mm pitch, 4000pcs
*
*
* It has a 43K feed resistor from 3V3
*
* Thermistor Voltage = V_supply * ADC_value / 4096
* Thermistor Resistance = R_feed / ( ( V_supply / V_thermistor ) - 1 )
* Temp in kelvin = 1 / ( ( ln( R_thermistor / R_0 ) / B ) + 1 / T_0 )
* Where: R_feed = 43k, V_supply = 3V3, R_0 = 10k, B = 3375, T_0 = 298.15°K (25°C)
*/
if (result == WICED_SUCCESS)
{
double thermistor_resistance = 43000.0 / ( ( 4096.0 / (double) *sample_value ) - 1 );
double logval = log( thermistor_resistance / 10000.0 );
double temperature = 1.0 / ( logval / 3380.0 + 1.0 / 298.15 ) - 273.15;
*sample_value = (uint16_t)(temperature*10);
return WICED_SUCCESS;
}
else
{
*sample_value = 0;
return result;
}
}
/*
* Main application
*/
void application_start( void )
{
char *msg = MSG_OFF;
wiced_result_t ret = WICED_SUCCESS;
int retries;
uint16_t light_value;
ret = aws_app_init(&app_info);
/* Initialise Light sensor */
WPRINT_APP_INFO( ("Initializing Light Sensor\n" ));
wiced_adc_init( WICED_LIGHT, 5 );
do
{
ret = aws_mqtt_conn_open( app_info.mqtt_object, mqtt_connection_event_cb );
if ( ret != WICED_SUCCESS )
{
WPRINT_APP_INFO(("Failed\n"));
break;
}
while ( 1 )
{
/* Read light sensor */
wiced_adc_take_sample( WICED_LIGHT, &light_value );
WPRINT_APP_INFO( ("Light value %u\n", light_value) );
if ( light_value >= LIGHT_THRESHOLD )
{
msg = MSG_ON;
}
else
{
msg = MSG_OFF;
}
/* Controlling the LED by publishing to mqtt topic "WICED_BULB" */
retries = 0;
do
{
ret = aws_mqtt_app_publish( app_info.mqtt_object, WICED_MQTT_QOS_DELIVER_AT_LEAST_ONCE, (uint8_t*) app_info.thing_name, (uint8_t*) msg, strlen( msg ) );
retries++ ;
} while ( ( ret != WICED_SUCCESS ) && ( retries < MQTT_PUBLISH_RETRY_COUNT ) );
if ( ret != WICED_SUCCESS )
{
break;
}
wiced_rtos_delay_milliseconds( 5000 );
}
aws_mqtt_conn_close( app_info.mqtt_object );
wiced_rtos_delay_milliseconds( MQTT_DELAY_IN_MILLISECONDS * 2 );
} while ( 1 );
aws_mqtt_conn_close( app_info.mqtt_object );
wiced_rtos_deinit_semaphore( &app_info.msg_semaphore );
WPRINT_APP_INFO(("[MQTT] Deinit connection...\n"));
ret = wiced_mqtt_deinit( app_info.mqtt_object );
free( app_info.mqtt_object );
app_info.mqtt_object = NULL;
return;
}
