File content as of revision 10:149ded218037:

#include "mbed.h"
#include "math.h"

Serial pc (USBTX, USBRX);
Serial xbee (PTE0, PTE1);

const int ARRAY_LENGTH    = 50;
float temperature_celsius, temperature_voltage, light_voltage, raw_pir_reading, noise_voltage, noise_maximum, noise_average, noise_total, noise_variance, noise_sd, presence_percentage, num_consecutive_runs;
char publishString[40];
float noise_array[ARRAY_LENGTH];
int pir_array[ARRAY_LENGTH];

//bool DEBUG_MODE = false;

AnalogIn light_ain(A0);
AnalogIn temp_ain(A1);
AnalogIn pir_ain(A2);
AnalogIn noise_ain(A3);

void publish_measurements() {
    temperature_voltage = temp_ain.read_u16();
    // Convert DAC reading to millivolts
    temperature_voltage = (temperature_voltage * 3.3 * 1000) / 4095;
    // Convert millivolts to Celsius using datasheet equation
    temperature_celsius = (2103 - temperature_voltage) / 10.9;
    //if(DEBUG_MODE) {
        //Serial.println("Temperature (Celsius): " + String(temperature_celsius));
    //}

    light_voltage = light_ain.read_u16();

    sprintf(publishString,"%.1f, %.1f, %.1f, %.1f, %.1f", temperature_celsius, light_voltage, noise_maximum, noise_average, noise_variance);
    xbee.printf(publishString);
    pc.printf("publish");
    pc.printf(publishString);
    sprintf(publishString, "%.1f, %.1f", presence_percentage, num_consecutive_runs);
    xbee.printf(publishString);
}


void measure_pir_and_noise() {
    noise_voltage = 0;

    for (int i = 0; i < ARRAY_LENGTH; i++) {
        raw_pir_reading = pir_ain.read_u16();
        noise_voltage = noise_ain.read_u16();
        noise_array[i] = noise_voltage;
        if (raw_pir_reading > 3000) {
            pir_array[i] = 1;
        } else {
            pir_array[i] = 0;
        }
        //if (DEBUG_MODE) {
            //Serial.println("PIR: " + String(raw_pir_reading));
            //Serial.println("Noise: " + String(noise_voltage));
        //}
        wait(0.1);
    }
}


void noise_analysis() {
    float residuals[ARRAY_LENGTH];
    noise_maximum = 0;
    noise_average = 0;
    noise_variance = 0;
    noise_total = 0;

    for (int i = 0; i < ARRAY_LENGTH; i++) {
        if (noise_array[i] > noise_maximum) noise_maximum = noise_array[i];
        noise_total += noise_array[i];
    }
    noise_average = noise_total / (ARRAY_LENGTH * 1.0);

    for (int i = 0; i < ARRAY_LENGTH; i++) {
        residuals[i] = noise_array[i] - noise_average;
        noise_variance += residuals[i] * residuals[i];
    }
    noise_variance = noise_variance / (ARRAY_LENGTH * 1.0);
}


void pir_analysis() {
    int counts_over_1s = 0;
    int longest_consecutive_run = 0;
    int curr_num_consecutive = 0;

    counts_over_1s = pir_array[0] == 1 ? 1 : 0;
    for (int i = 1; i < ARRAY_LENGTH; i++) {
        if (pir_array[i] == 1) {
            ++counts_over_1s;
        }
        if (pir_array[i] == 1 && pir_array[i-1] == 1) {
            ++curr_num_consecutive;
        } else {
            if (curr_num_consecutive > longest_consecutive_run) {
                longest_consecutive_run = curr_num_consecutive;
                curr_num_consecutive = 0;
            }
        }
    }

    presence_percentage = 100 * counts_over_1s * 1.0 / ARRAY_LENGTH;
    num_consecutive_runs = longest_consecutive_run;
}


int main() {
    while (1) {        
  measure_pir_and_noise();
  noise_analysis();
  pir_analysis();
  publish_measurements();
  
}
}