Ignitor.cpp

#include "mbed.h"
#include <cmath>
#include <vector>

// Constants for Goertzel algorithm
const float f_target = 100; // Target frequency [Hz]
const float fs = 1000;      // Sampling frequency [Hz]
const int N = 100;          // Number of samples for Goertzel algorithm

// Goertzel algorithm variables
float r, s, w;          // Goertzel coefficients
float x_prev1 = 0;      // Previous output x(n-1)
float x_prev2 = 0;      // Previous output x(n-2)
float amplitude = 0;    // Amplitude of the target frequency
float phase = 0;        // Phase of the target frequency

// Data buffer for the moving window
std::vector<float> data_window;

// Simulated GPIO setup function (replace this with your actual setup logic)
void setupGPIO(int pin, bool mode) {
    std::cout << "Setting up GPIO pin " << pin << " in mode " << mode << std::endl;
}

// Simulated GPIO read function (replace this with your actual reading logic)
bool readGPIO(int pin) {
    std::cout << "Reading from GPIO pin " << pin << std::endl;
    return true;  // Replace this with the actual reading logic
}

float readFlowSensor(int pin) {
    setupGPIO(pin, false);  // Replace false with the actual mode for input

    int flowRate = 0;

    // Simulate periodic readings (for demonstration purposes)
    for (int i = 0; i < 5; ++i) {  // Simulate 5 readings (adjust as needed)
        // Assuming you have some delay to simulate periodic readings
        std::this_thread::sleep_for(std::chrono::seconds(1));

        // Simulated pulse detection (replace this with actual logic)
        if (readGPIO(pin)) {
            flowRate++;
        }
    }

    return flowRate;
}

// Function to calculate the Goertzel coefficients
void calcGoertzelCoefficients() {
    int k = static_cast<int>(N * f_target / fs);
    float theta = 2 * 3.14159 * k / N;
    r = 2.0 * cos(theta);
    s = sin(theta);
    w = 2.0 * cos(2 * theta);
}

// Function to perform the Goertzel algorithm and obtain amplitude and phase data
void performGoertzelAlgorithm(float x_curr) {
    float x_temp = x_curr + r * x_prev1 - x_prev2;
    x_prev2 = x_prev1;
    x_prev1 = x_temp;

    // Calculate magnitude squared (amplitude squared) from Goertzel output
    float x_result = x_prev2 * x_prev2 + x_prev1 * x_prev1 - r * x_prev1 * x_prev2;
    // Convert magnitude squared to amplitude and phase
    amplitude = sqrt(x_result);
    phase = atan2(x_prev1, x_prev2);
}

int main() {
    // Initializing and configuring microcontroller peripherals and GPIO pins

    calcGoertzelCoefficients();

    while (true) {
        // Read the input signal from the flow sensor
        float input_signal = readFlowSensor(); // Replace readFlowSensor() with actual function to read from flow sensor

        // Add the new data point to the data_window
        data_window.push_back(input_signal);

        // If the size of data_window exceeds N, remove the oldest data point
        if (data_window.size() > N) {
            data_window.erase(data_window.begin());
        }

        // Perform Goertzel algorithm on the data in the data_window
        performGoertzelAlgorithm(input_signal);

        // Fourier series approximation using Goertzel-derived amplitude and phase data
        float t = 0; // Time variable for generating the Fourier series
        float sum = 0; // Sum of the Fourier series
        for (int i = 0; i < data_window.size(); i++) {
            // Generate the ith harmonic component and add it to the sum
            sum += amplitude * cos(2 * 3.14159 * f_target * t / fs + phase);
            t += 1.0 / fs;
        }

        // Additional code for using the Fourier series approximation (sum)
        // For example, you can use 'sum' to represent the approximated signal.
        // ...

        // Additional code for the main loop
        // ...
    }
}