student.c

/* 
=== HOW TO RUN ===
Step 1: cd into C file location
Step 2: gcc -o student student.c -lwiringPi
Step 3: ./student

=== PRE-REQUISITES ===
Install wiringPi: https://learn.sparkfun.com/tutorials/raspberry-gpio/c-wiringpi-setup
softPwm is installed with wiringPi

=== USEFUL COMMANDS ===
Check wiringPi version: gpio -v
Check GPIO status: gpio readall

=== GPIO PIN CONNECTION ===
27 GREEN LED
13 RED LED
GROUND

GPIO14 to Monitor GPIO15
GPIO15 to Monitor GPIO14
GROUND

=== RASPBERRY PI VERSION ===
Check Version Command: cat /etc/os-release

PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
*/

#include <wiringPi.h> // Only in raspberry pi system
#include <softPwm.h> // Only in raspberry pi system
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wiringSerial.h> // Only in raspberry pi system
#include <unistd.h>

/* DEFINITIONS */
#define RED 27      // GPIO Pin 27
#define GREEN 13    // GPIO Pin 13

// Program States
#define TURN_OFF 0
#define TURN_ON 1
#define BLINK 2
#define EXIT 3

// LED Blink Selection
#define BLINK_GREEN 1
#define BLINK_RED 2
#define CONFIRM 1

// MONITORING
#define STUDENTID "2101234"     // the student ID is not needed in the group project of 2023

/* FUNCTION PROTOTYPES */
void setupProgram();
void startProgram();
int getUserSelection();
void turnOffLeds();
void turnOnLeds();
void blink();
int getBlinkLed();
int getBlinkFrequency();
int getBlinkBrightness();
int confirmBlinkSelection();
int connectToMonitorDevice();
void blinkLedWithConfig();
void endProgram();


/* MAIN PROGRAM */
int main(void) {

    setupProgram();
    startProgram();
    endProgram();
    return 0;
}

/* 
Sets up the LED GPIO pins as output and PWM
*/
void setupProgram() {
    wiringPiSetupGpio();
    pinMode(RED, OUTPUT);
    pinMode(GREEN, OUTPUT);
    softPwmCreate(GREEN, 0, 100);
    softPwmCreate(RED, 0, 100);
    system("clear");
}

/* 
Takes the input of the user selection and direct it to different states of the program
*/
void startProgram() {

    int selection;

    do {
        selection = getUserSelection();

        switch(selection) {

            case TURN_OFF:
                turnOffLeds();
                break;
            case TURN_ON:
                turnOnLeds();
                break;
            case BLINK:
                blink();
                break;
            case EXIT:
                break;
            default:
                printf("\nInvalid Input. Try Again...\n");
                break;
        }

    } while (selection != EXIT);
    
    return;
}

/* 
The main menu that determines what the user wants to do
*/
int getUserSelection() {

    int selection;

    printf("\n===== LAD STUDENT DEVICE =====\n");
    printf("\n[0] Turn off both LEDs\n");
    printf("[1] Turn on both LEDs\n");
    printf("[2] Blink LED\n");
    printf("[3] Exit\n");
    printf("\nYour Selection: ");

    scanf("%d", &selection);

    return selection;
}

/* 
For troubleshooting, turning off LEDs and PWM
*/
void turnOffLeds() {
    system("clear");
    printf("\nTurning off both LEDs...\n");
    digitalWrite(GREEN, LOW);
    softPwmWrite(GREEN, 0);
    digitalWrite(RED, LOW);
    softPwmWrite(RED, 0);
}

/* 
For troubleshooting, turning on LEDs and PWM at 100
*/
void turnOnLeds() {
    system("clear");
    printf("\nTurning on both LEDs...\n");
    digitalWrite(GREEN, HIGH);
    softPwmWrite(GREEN, 100);
    digitalWrite(RED, HIGH);
    softPwmWrite(RED, 100);
}

/* 
When user wants to blink LED, this function will get all the blinking configuration
It gets from the user the LED to blink, frequency and brightness.
Then, it will call a function to attempt handshake with Monitor before executing the blink
*/
void blink() {
    system("clear");
    printf("\nBlink...\n");
    
    int blinkLed = getBlinkLed();
    int frequency = getBlinkFrequency();
    int brightness = getBlinkBrightness();

    if (confirmBlinkSelection(blinkLed, frequency, brightness) == CONFIRM) {

        if (connectToMonitorDevice(blinkLed, frequency, brightness) < 0) {
            printf("Connection failed, please make sure monitor device is ready.\n");
        } else {
            blinkLedWithConfig(blinkLed, frequency, brightness);
            system("clear");
        }

    } else return;

}

/* 
Menu to get user selction on LED to blink
*/
int getBlinkLed() {

    int selection;

    printf("\nSelect LED to blink.\n\n");
    printf("[1] Green LED\n");
    printf("[2] Red LED\n");
    printf("\nYour Selection: ");

    scanf("%d", &selection);

    if (selection != BLINK_GREEN && selection != BLINK_RED) {
        system("clear");
        printf("Invalid Input. Try Again...\n\n");
        getBlinkLed();
    } else {
        system("clear");
        return selection;
    }
}

/* 
Menu to get user selction on Frequency to blink
*/
int getBlinkFrequency() {

    int selection;

    printf("Enter frequency to blink.\n\n");
    printf("Enter whole numbers between 0 to 10\n");
    printf("\nFrequency (Hz): ");

    scanf("%d", &selection);

    if (selection < 0 || selection > 10) {
        system("clear");
        printf("Invalid Input. Try Again...\n\n");
        getBlinkFrequency();
    } else {
        system("clear");
        return selection;
    }
}

/* 
Menu to get user selction on LED brightness
*/
int getBlinkBrightness() {

    int selection;

    printf("Select LED brightness during blink.\n\n");
    printf("Enter whole numbers between 0 to 100\n");
    printf("Brightness (%%): ");

    scanf("%d", &selection);

    if (selection < 0 || selection > 100) {
        system("clear");
        printf("Invalid Input. Try Again...\n\n");
        getBlinkBrightness();
    } else {
        system("clear");
        return selection;
    }

}

/* 
Menu for user to acknowldge the blink configurations input
*/
int confirmBlinkSelection(int blinkLed, int blinkFrequency, int blinkBrightness) {
    
    int selection;
    char blinkLedString[] = "Green";

    if (blinkLed == BLINK_RED) {
        strcpy(blinkLedString, "Red");
    }

    printf("Confirm your blink configrations.\n\n");
    printf("LED to blink: %s\n", blinkLedString);
    printf("Blink Frequency: %dHz\n", blinkFrequency);
    printf("Blink Brightness: %d%%\n\n", blinkBrightness);
    printf("[1] Confirm Configuration\n");
    printf("[0] Return to Home\n");
    printf("\nYour Selection: ");

    scanf("%d", &selection);

    if (selection < 0 || selection > 1) {
        system("clear");
        printf("Invalid Input. Try Again...\n\n");
        confirmBlinkSelection(blinkLed, blinkFrequency, blinkBrightness);
    } else {
        return selection;
    }
}

/* 
Handshake algorithm to connect and send blink configurations
*/
int connectToMonitorDevice(int blinkLed, int blinkFrequency, int blinkBrightness) {
    system("clear");
    printf("Connecting to Monitor Device...\n");
    
    int serial_port;
    char studentid[] = STUDENTID;

    char blinkLedString[1];
    char blinkFrequencyString[2];
    char blinkBrightnessString[3];

    sprintf(blinkLedString, "%d", blinkLed);
    sprintf(blinkFrequencyString, "%d", blinkFrequency);
    sprintf(blinkBrightnessString, "%d", blinkBrightness);

    // Open the serial port
    serial_port = serialOpen("/dev/ttyAMA0", 9600);
    if (serial_port < 0) {
    fprintf(stderr, "Error opening serial port\n");
        return -1;
    }

    // Write data to the serial port
    serialPuts(serial_port, studentid);

    // Read data from the serial port
    char buffer[256];
    int n = read(serial_port, buffer, sizeof(buffer));
    buffer[n] = '\0';

    if (strlen(buffer) == 7) {
        printf("Acknowledge Student ID: %s\n", buffer);
    } else return -1;    

    // Send Blink Configuration
    serialPuts(serial_port, blinkLedString);
    n = read(serial_port, buffer, sizeof(buffer));
    buffer[n] = '\0';
    printf("%s\n", buffer);

    serialPuts(serial_port, blinkFrequencyString);
    n = read(serial_port, buffer, sizeof(buffer));
    buffer[n] = '\0';
    printf("%s\n", buffer);

    serialPuts(serial_port, blinkBrightnessString);
    n = read(serial_port, buffer, sizeof(buffer));
    buffer[n] = '\0';
    printf("%s\n", buffer);

    serialClose(serial_port);
    printf("Connection Successful!\n");
    delay(5000);
    return 1;
}

/* 
Blinks the LED according to the user configuration
*/
void blinkLedWithConfig(int blinkLed, int blinkFrequency, int blinkBrightness) {

    printf("\nBlinking...\n");
    
    // Setting Frequency
    float onOffTime = 1.0f / blinkFrequency * 1000;

    // Setting Blink LED
    if (blinkLed == BLINK_GREEN) {
        blinkLed = GREEN;
    } else blinkLed = RED;

    // Blinking
    unsigned long previousMillis = 0;
    int ledState = LOW;

    for (int blink = 0; blink < 20;)
    {
        unsigned long currentMillis = millis();

        if (currentMillis - previousMillis >= onOffTime) {
            previousMillis = currentMillis;
            if (ledState == LOW) {
                ledState = HIGH;
                softPwmWrite(blinkLed, blinkBrightness);
            } else {
                ledState = LOW;
                softPwmWrite(blinkLed, 0);
            }
            blink++;
            digitalWrite(blinkLed, ledState);
        }
    }

}

/* 
Resetting and cleaning up before safely exiting the program.
*/
void endProgram() {
    system("clear");
    printf("\nCleaning Up...\n");
    // Turn Off LEDs
    digitalWrite(GREEN, LOW);
    digitalWrite(RED, LOW);

    // Turn Off LED Software PWM
    softPwmWrite(GREEN, 0);
    softPwmWrite(RED, 0);

    // Reset Pins to Original INPUT State
    pinMode(GREEN, INPUT);
    pinMode(RED, INPUT);

    printf("Bye!\n\n");
}