a2d_display_client.c File Reference

#include "skn_network_helpers.h"
#include <wiringPi.h>
#include <pcf8591.h>
#include <math.h>

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Macros
#define	A2D_BASE   120
#define	LED   120
#define	A2D_THERM   A2D_BASE + 2
#define	A2D_PHOTO   A2D_BASE + 3
#define	THERMISTORNOMINAL   10000
#define	TEMPERATURENOMINAL   25
#define	BCOEFFICIENT   4207.0
#define	SERIESRESISTOR   10240
#define	A2D_PERCISION   255.0
#define	MAXREADS   5
#define	sA   1.129148E-03
#define	sB   2.34125E-04
#define	sC   8.76741E-08
#define	calibrationOffset   -0.5

Functions
double	adcToOhms (int rawADC)
double	steinhartAdcToCelsius (int rawADC)
double	betaAdcToCelsius (int rawADC)
double	readAverageSensorValue (int sensor)
int	sknGetModuleTemp (char *buffer)
int	sknGetModuleBright (char *buffer)
int	main (int argc, char *argv[])

Macro Definition Documentation

#define A2D_BASE   120

a2d_display_client.c

• Display Room Temperature Client Supports** for 'AD / DA Shield Module For Raspberry Pi'

which is based on the I2C controller PCF8591T to access:

• - on-board temperature sensor; NTC, MF58103J3950, B value 3950K, 1 K ohm 5% Cantherm
• - on-board light sensors; GL5537-1 CdS Photoresistor
• example: **_a2d_display_client -i 73_**

Definition at line 17 of file a2d_display_client.c.

Referenced by main().

#define A2D_PERCISION   255.0

Definition at line 34 of file a2d_display_client.c.

Referenced by adcToOhms().

#define A2D_PHOTO   A2D_BASE + 3

Definition at line 20 of file a2d_display_client.c.

Referenced by sknGetModuleBright().

#define A2D_THERM   A2D_BASE + 2

Definition at line 19 of file a2d_display_client.c.

Referenced by sknGetModuleTemp().

#define BCOEFFICIENT   4207.0

Definition at line 30 of file a2d_display_client.c.

Referenced by betaAdcToCelsius().

#define calibrationOffset   -0.5

Definition at line 43 of file a2d_display_client.c.

Referenced by betaAdcToCelsius(), and steinhartAdcToCelsius().

#define LED   120

Definition at line 18 of file a2d_display_client.c.

Referenced by main().

#define MAXREADS   5

Definition at line 36 of file a2d_display_client.c.

Referenced by readAverageSensorValue().

#define sA   1.129148E-03

Definition at line 40 of file a2d_display_client.c.

Referenced by steinhartAdcToCelsius().

#define sB   2.34125E-04

Definition at line 41 of file a2d_display_client.c.

Referenced by steinhartAdcToCelsius().

#define sC   8.76741E-08

Definition at line 42 of file a2d_display_client.c.

Referenced by steinhartAdcToCelsius().

#define SERIESRESISTOR   10240

Definition at line 32 of file a2d_display_client.c.

Referenced by adcToOhms().

#define TEMPERATURENOMINAL   25

Definition at line 28 of file a2d_display_client.c.

Referenced by betaAdcToCelsius().

#define THERMISTORNOMINAL   10000

Definition at line 26 of file a2d_display_client.c.

Referenced by betaAdcToCelsius().

Function Documentation

double adcToOhms

(

int

rawADC

)

Convert rawADC into Ohms

Definition at line 48 of file a2d_display_client.c.

References A2D_PERCISION, and SERIESRESISTOR.

Referenced by betaAdcToCelsius(), and steinhartAdcToCelsius().

                               {
  double resistance = 0.0;

  resistance = (double)(( A2D_PERCISION / rawADC) - 1.0);
  resistance = (double)( SERIESRESISTOR / resistance );

  return resistance;
}

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double betaAdcToCelsius

(

int

rawADC

)

Inputs ADC Value from Thermistor and outputs Temperature in Celsius

Utilizes the Beta Factor Equation: 1/T = 1/To + 1/B * ln(R/Ro) I'm concerned about R1, in resistance, which is really 1K not 10K https://learn.adafruit.com/thermistor/using-a-thermistor

Definition at line 87 of file a2d_display_client.c.

References adcToOhms(), BCOEFFICIENT, calibrationOffset, TEMPERATURENOMINAL, and THERMISTORNOMINAL.

                                    {
  double kelvin = 0.0, celsius = 0.0;

  kelvin = adcToOhms(rawADC) / THERMISTORNOMINAL;  // (R/Ro)
  kelvin = log(kelvin);                            // ln(R/Ro)
  kelvin /= BCOEFFICIENT;                          // 1/B * ln(R/Ro)
  kelvin += 1.0 / (TEMPERATURENOMINAL + 273.15);   // + (1/To)
  kelvin = 1.0 / kelvin;                           // Invert

  celsius = kelvin - 273.15;                       // convert to C from Kelvins

  return celsius + calibrationOffset; // Return the Temperature in C, with correction offset
}

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int main	(	int	argc,
		char *	argv[]
	)

Definition at line 170 of file a2d_display_client.c.

References A2D_BASE, gd_i_i2c_address, gd_i_socket, gd_i_update, gd_pch_message, gd_pch_service_name, gi_exit_flag, _serviceEntry::ip, LED, _serviceEntry::name, _serviceEntry::port, _serviceRequest::request, SD_DEBUG, SD_NOTICE, SD_WARNING, service_registry_destroy(), service_registry_entry_count(), service_registry_find_entry(), service_registry_get_via_udp_broadcast(), signals_cleanup(), signals_init(), skn_handle_locator_command_line(), skn_program_name_and_description_set(), SKN_RUN_MODE_RUN, skn_service_request_create(), skn_udp_host_create_broadcast_socket(), skn_udp_host_create_regular_socket(), skn_udp_service_request(), sknGetModuleBright(), sknGetModuleTemp(), SZ_CHAR_BUFF, and SZ_INFO_BUFF.

{
    char request[SZ_INFO_BUFF];
    char registry[SZ_CHAR_BUFF];
    PServiceRegistry psr = NULL;
    PRegistryEntry pre = NULL;
    PServiceRequest pnsr = NULL;
    int vIndex = 0;

    gd_i_i2c_address = 0;

    memset(registry, 0, sizeof(registry));
    memset(request, 0, sizeof(request));
    strncpy(registry, "DisplayClient: Raspberry Pi where are you?", sizeof(registry) - 1);

    skn_program_name_and_description_set(
            "a2d_display_client",
            "Send Measured Temperature and Light(lux) to Display Service."
    );

    /* Parse any command line options,
     * like request string override */
    if (skn_handle_locator_command_line(argc, argv) == EXIT_FAILURE) {
        exit(EXIT_FAILURE);
    }
    if (gd_pch_message != NULL) {
            strncpy(request, gd_pch_message, sizeof(request));
        free(gd_pch_message); // from strdup()
        gd_pch_message = request;
    } else if (argc == 2) {
            strcpy(request, argv[1]);
    }

    skn_logger(SD_DEBUG, "Request  Message [%s]", request);
    skn_logger(SD_DEBUG, "Registry Message [%s]", registry);

    /* Initialize Signal handler */
    signals_init();

    // wiringPiSetup () ;
    wiringPiSetupSys();

    // Add in the pcf8591
    if (gd_i_i2c_address == 0) {
        gd_i_i2c_address = 0x49;
    }
    pcf8591Setup (A2D_BASE, gd_i_i2c_address) ;

    pinMode (LED, OUTPUT) ;   // On-board LED
    analogWrite(LED, 0) ;     // Turn off the LED

    /* Create local socket for sending requests */
    gd_i_socket = skn_udp_host_create_broadcast_socket(0, 4.0);
    if (gd_i_socket == EXIT_FAILURE) {
        signals_cleanup(gi_exit_flag);
        exit(EXIT_FAILURE);     
    }

    skn_logger(SD_NOTICE, "Application Active...");

    /* Get the ServiceRegistry from Provider
     * - could return null if error */
    psr = service_registry_get_via_udp_broadcast(gd_i_socket, registry);
    if (psr != NULL && service_registry_entry_count(psr) != 0) {
        char *service_name = "lcd_display_service";

        if (gd_pch_service_name != NULL) {
            service_name = gd_pch_service_name;
        }

        /* find a single entry */
        pre = service_registry_find_entry(psr, service_name);
        if (pre != NULL) {
            skn_logger(" ", "\nLCD DisplayService (%s) is located at IPv4: %s:%d\n", pre->name, pre->ip, pre->port);
        }

        /*
         * Switch to non-broadcast type socket */
        close(gd_i_socket); gd_i_socket = -1;
        gd_i_socket = skn_udp_host_create_regular_socket(0, 8.0);
        if (gd_i_socket == EXIT_FAILURE) {
            if (psr != NULL) service_registry_destroy(psr);
            signals_cleanup(gi_exit_flag);
            exit(EXIT_FAILURE);
        }
    }

    // we have the location
    if (pre != NULL) {
        if (request[0] == 0) {
            sknGetModuleTemp(request);
        }
        pnsr = skn_service_request_create(pre, gd_i_socket, request);
    }
    if (pnsr != NULL) {
        do {
            analogWrite(LED, 255) ; // Flicker the LED

            /*
             * Do Work */
            sknGetModuleTemp(pnsr->request);
            vIndex = skn_udp_service_request(pnsr);
            if ((vIndex == EXIT_FAILURE) && (gd_i_update == 0)) { // ignore if non-stop is set
                break;
            }

            sleep(3);

            /*
             * Do Work */
            sknGetModuleBright(pnsr->request);
            vIndex = skn_udp_service_request(pnsr);
            if ((vIndex == EXIT_FAILURE) && (gd_i_update == 0)) { // ignore if non-stop is set
                break;
            }

            analogWrite(LED, 0) ; // Flicker the LED

            sleep(gd_i_update);
        } while(gd_i_update != 0 && gi_exit_flag == SKN_RUN_MODE_RUN);
        free(pnsr);  // Done

    } else {
        skn_logger(SD_WARNING, "Unable to create Network Request.");
    }

    /* Cleanup and shutdown
     * - if shutdown was caused by signal handler
     *   then a termination signal will be sent via signal()
     *   otherwise, a normal exit occurs
     */
    analogWrite(LED, 0) ; // LED off
    if (gd_i_socket) close(gd_i_socket);
    if (psr != NULL) service_registry_destroy(psr);
    signals_cleanup(gi_exit_flag);

    exit(EXIT_SUCCESS);
}

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double readAverageSensorValue

(

int

sensor

)

Averages sensor value from five reads

Definition at line 104 of file a2d_display_client.c.

References MAXREADS.

Referenced by sknGetModuleBright(), and sknGetModuleTemp().

                                          {
    int rvalue[MAXREADS+3], index;

    /*
     * Temperature Sensor */
    for (index = 0, rvalue[MAXREADS] = 0; index < MAXREADS; index++) {
        rvalue[index] = analogRead(sensor) ;
        rvalue[MAXREADS] += rvalue[index];
        delay(10);
    }

    return rvalue[MAXREADS] / MAXREADS * 1.0;
}

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int sknGetModuleBright

(

char *

buffer

)

Photo Resistor Brightness Indicator

Definition at line 141 of file a2d_display_client.c.

References A2D_PHOTO, readAverageSensorValue(), and SZ_INFO_BUFF.

Referenced by main().

                                     {
    double value = 0.0;
    char *plights;

    /*
     * Photo Sensor Lumens */
    value = readAverageSensorValue(A2D_PHOTO) ;
    value = 256.0 - value;

    if (value < 2.5) {
        plights = "Dark";
    } else if (value < 50.0) {
        plights = "Dim";
    } else if (value < 125.0) {
        plights = "Light";
    } else if (value < 199.0) {
        plights = "Bright";
    } else {
        plights = "Brightest";
    }

    /*
     * Write to output buffer */
    snprintf( buffer, (SZ_INFO_BUFF - 1), "%s", plights);

  return EXIT_SUCCESS;
}

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int sknGetModuleTemp

(

char *

buffer

)

Free Air Temps

Definition at line 121 of file a2d_display_client.c.

References A2D_THERM, readAverageSensorValue(), steinhartAdcToCelsius(), and SZ_INFO_BUFF.

Referenced by main().

                                   {
    double fTemp = 0.0, cTemp = 0.0, value = 0.0;

    value = readAverageSensorValue(A2D_THERM);

    /*
     * Steinhart Method */
    cTemp = steinhartAdcToCelsius(value);
    fTemp = (cTemp * 1.8) + 32.0;          // Convert to USA

    /*
     * Write to output buffer */
    snprintf( buffer, (SZ_INFO_BUFF - 1),"[A] %.0fC %.0fF", cTemp, fTemp);

  return EXIT_SUCCESS;
}

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double steinhartAdcToCelsius

(

int

rawADC

)

Inputs ADC Value from Thermistor and outputs Temperature in Celsius

Utilizes the Steinhart-Hart Thermistor Equation:

If r is the thermistor resistance we can use the Steinhart-Hart equation to calculate the temperature t in degrees kelvin: return Celsius t = 1 / (sA + sB * ln(r) + sC * ln(r) * ln(r) * ln(r))

Temperature in Kelvin = 1 / (A + B * ln(r) + C * ln(r) * ln(r) * ln(r)) where A = 0.001129148, B = 0.000234125 and C = 8.76741E-08

Definition at line 69 of file a2d_display_client.c.

References adcToOhms(), calibrationOffset, sA, sB, and sC.

Referenced by sknGetModuleTemp().

                                         {
  double kelvin = 0.0, celsius = 0.0;

  kelvin = log( adcToOhms(rawADC) );
  kelvin = 1 / (sA + (sB * kelvin) + sC * kelvin * kelvin * kelvin );
  celsius = kelvin - 273.15;  // Convert Kelvin to Celsius

  return celsius + calibrationOffset; // Return the Temperature in C, with correction offset
}

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