// This code mostly generated from ChatGPT.
// "Build a Arduino Uno project that can read a AC and DC voltage
// and display it on a ssd1306 oled display module. 
// Can you help me with arduino script and hardware connections."
//================================================================
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for SSD1306 display connected using software I2C (default case)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Analog pins for voltage sensors
const int pinDCVoltage = A0; // DC voltage divider output connected here
const int pinACVoltage = A1; // ZMPT101B module output connected here

void setup() {
  Serial.begin(115200);
  
  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Check your display's I2C address
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  display.display();
  delay(1000); // Pause 
  display.clearDisplay();

  // Set the analog reference to 5V
  analogReference(DEFAULT);
}

void loop() {
  // Read DC Voltage
  int sensorValueDC = analogRead(pinDCVoltage);
  float voltageDC = sensorValueDC * (5.0 / 1023.0) * ((1e6 + 200e3) / 200e3); // Example for a 1MΩ:200kΩ divider

  // Read AC Voltage (needs proper calibration and conversion)
  int sensorValueAC = analogRead(pinACVoltage);
  float voltageAC = sensorValueAC * (5.0 / 1023.0); // This will need to be scaled properly

  // Display Voltages on OLED
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.print("DC Voltage: ");
  display.print(voltageDC);
  display.println(" vDC");

  display.setCursor(0,10);
  display.print("AC Voltage: ");
  display.print(voltageAC);
  display.println(" vAC");

  display.display();
  
  // also send to serial port
  Serial.print("DC Voltage: ");
  Serial.print(voltageDC);
  Serial.println(" vDC");
  Serial.print("AC Voltage: ");
  Serial.print(voltageAC);
  Serial.println(" vAC");

  delay(500); // Update every half second
}