/*
* Author:IHSHANA THAHSIN
* Project: RETAIL SHELF MONITORING
* Description:This project integrates ESP32 and STM32 microcontrollers 
*              with load cells to monitor the weight of products on shelves.
*              The ESP32 handles data acquisition and communication, while 
*              the STM32 updates an LCD with the current weight. 
*/


#include <WiFi.h>
#include <ThingSpeak.h>
#include <HX711.h>
#include <LiquidCrystal_I2C.h>

#define LED 2
#define LED2 4

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int LOADCELL_DOUT_PIN = 15;
const int LOADCELL_SCK_PIN = 2;
const float calibration_factor = 100.0;

HX711 scale; 
long units;
char ssid[] = "Wokwi-GUEST";
char pass[] = "";

WiFiClient client;
unsigned long myChannelNumber = 2279390;
const char * myWriteAPIKey = "DMV9RHKW37I550XH";
int statusCode;

void setup() {
  Serial.begin(115200);

  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client);

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(calibration_factor);
  scale.tare();

  Serial.println("Hello, ESP32!");

  lcd.init();
  lcd.backlight();

  pinMode(LED, OUTPUT);
  pinMode(LED2, OUTPUT);
}

void loop() {
  // Generate a random weight value between 0 and 5 kg
  float simulated_weight = random(0, 5000) / 1000.0; // Random weight between 0 and 5 kg
  
  // LED control logic
  digitalWrite(LED, HIGH);
  digitalWrite(LED2, LOW);
  delay(500);
  digitalWrite(LED, LOW);
  digitalWrite(LED2, HIGH);
  delay(500);

  // Attempt to connect to WiFi if not connected
  if(WiFi.status() != WL_CONNECTED) {
    Serial.print("Attempting to connect");
    while(WiFi.status() != WL_CONNECTED) {
      WiFi.begin(ssid, pass); 
      Serial.print(".");
      delay(1000);
    }
    Serial.println("\nConnected.");
  }

  // Print the simulated weight on the LCD and serial monitor
  Serial.print("Weight: ");
  lcd.setCursor(2, 0);
  lcd.print("Weight :");
  lcd.print(simulated_weight);
  lcd.print(" kg");
  Serial.print(simulated_weight);
  Serial.println(" kg");

  delay(1000);

  // Update ThingSpeak channel with the simulated weight data
  ThingSpeak.setField(1, simulated_weight);
  statusCode = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);

  if(statusCode) { // Successful writing code
    Serial.println("Channel update successful.");
  } else {
    Serial.println("Problem Writing data. HTTP error code :" + String(statusCode));
  }

  delay(1000);
}