// MT3608 DC-DC Step-Up Converter Output Voltage Measurement
// Using Arduino analog input with a voltage divider

const int analogPin = A0;             // Analog pin connected to voltage divider output
const float referenceVoltage = 5.0;  // Arduino ADC reference voltage (typically 5V)
const int adcMaxValue = 1023;         // ADC max value for 10-bit resolution (0-1023)

// Voltage divider resistor values (Ohms)
// Actual output voltage = Measured voltage * (R1 + R2) / R2
const float R1 = 20000.0;             // Resistor from MT3608 output to analog pin (top resistor)
const float R2 = 10000.0;             // Resistor from analog pin to ground (bottom resistor)

void setup() {
  Serial.begin(9600);
  Serial.println("Starting MT3608 Output Voltage Measurement...");
}

void loop() {
  int adcValue = analogRead(analogPin);                         // Read raw ADC value
  float measuredVoltage = (adcValue * referenceVoltage) / adcMaxValue;  // Voltage at analog pin
  float outputVoltage = measuredVoltage * (R1 + R2) / R2;       // Calculate actual MT3608 output voltage

  Serial.print("Output Voltage: ");
  Serial.print(outputVoltage, 2);                               // Print voltage with 2 decimal places
  Serial.println(" V");

  delay(1000);                                                  // Delay 1 second before next reading
}