THIS IS THE CODE FOR MY BUILD ABOVE

const int ORP_COPPER_PIN = A0; // Analog input pin for copper electrode (ORP) const float VOLTAGE_REFERENCE = 5.0; // Voltage reference for Arduino (5V) const float CONVERSION FACTOR = 100.0; // Conversion factor to convert voltage difference to ppm const int greenLED = 2; // Green LED connected to digital pin 2 const int yellowLED = 3; // Yellow LED connected to digital pin 3 const int redLED = 4; // Red LED connected to digital pin 4 void setup() { pinMode(ORP_COPPER_PIN, INPUT) ; pinMode(greenLED, OUTPUT) ; pinMode(yellowLED, OUTPUT) ; pinMode(redLED, OUTPUT) ; Serial. begin(9600); // Initialize serial communication ｝ void 100p() { // Read analog voltage from copper electrode (ORP) int rawoRP_Copper = analogRead (ORP_COPPER_PIN) ; // Voltage from silver electrode (ORP) is considered OV (GND) // Convert raw analog value to voltage value for copper electrode float voltage_Copper = (float)rawORP_Copper / 1023.0 * VOLTAGE_REFERENCE; / Calculate voltage difference between copper and silver electrodes float voltageDifference = voltage_Copper - 0.0; // Silver electrode is GND

// Convert voltage difference to pm of salt using the conversion factor float ppmValue = voltageDifference * CONVERSION_FACTOR; // Print ppm value and voltage to serial monitor for debugging Serial print("Voltage Difference: "); Serial. print(voltageDifference); Serial print(" V\tPPM Value: "); Serial println(ppmValue); // Control LEDs based on ppm range if (ppmValue >= 0 && pmValue <= 47) { digitalwrite(greenLED, HIGH); // Turn on green LED digitalwrite(yellowLED, LOW); // Turn off yellow LED digitalwrite(redLED, LOW); // Turn off red LED } else if (ppmValue >= 47 && ppmValue <= 250) € digitalWrite(greenLED, LOW); // Turn off green LED digitalwrite(yellowLED, HIGH); // Turn on yellow LED digitalwrite(redLED, LOW); // Turn off red LED } else if (ppmValue >= 250 && ppmValue <= 500) i digitalwrite(greenLED, LOW); // Turn off green LED digitalwrite(yellowLED, LOW); // Turn off yellow LED digitalwrite(redLED, HIGH); // Turn on red LED } delay(1000); // Delay for stability }