This project involves measurement of voltages up to ±250 V (500 V peak-to-peak) using a 100:1 high-voltage divider.

⚡ These voltage levels are lethal.

Only trained and competent persons familiar with electrical safety, insulation, creepage/clearance, and high-voltage hazards should work with such circuits.

This information is provided strictly for educational purposes.

This example demonstrates how to measure and calculate power consumption using an Arduino UNO and an ACS758 current sensor (and voltage divider). The system computes:

• RMS Voltage
• RMS Current
• Power (Watts)
• Power Factor
• Energy (Wh, kWh, Joules), stored in EEPROM

• Voltage & Current Measurement: Voltage is read using a divider into A0, current using ACS758 into A1.
• Power Calculation: The Arduino calculates RMS voltage, RMS current, real power and apparent power.
• Energy Accumulation: Energy is tracked over time in Wh, kWh, and Joules.

/*
 * Arduino UNO Power Measurement with Energy Calculation
 * Measures RMS voltage, RMS current, power, and energy consumption.
 * Uses ACS758 ADC for accurate measurement.
 */

const int voltagePin = A0;    // Voltage divider connected to A0
const int currentPin = A1;    // Current sensor connected to A1

const float voltageDividerRatio = 200.0; // Voltage divider ratio (e.g., 200:1)
const float adcMaxVoltage = 5.0;         // Maximum ADC voltage (5V)
const float maxADCValue = 1023.0;        // Maximum ADC value
const float samplingInterval = 60.0;     // Sampling interval in seconds

// Setup ACS758
ACS758 ads(0x48); // Create ACS758 object with I2C address

// Energy variables
float totalEnergyWh = 0.0;
float totalEnergyJ = 0.0;

void setup() {
    Serial.begin(115200);
    Serial.println("Arduino PFC measurement, by Peter Ivan Dunne, ©2024, all rights reserved");
    Serial.println("Released under the Mozilla Public License");
    Serial.println("https://jazenga.com/educational");
    Serial.println("Provides RMS voltage, RMS current, Power factor, Total energy and Frequency");
}

void loop() {
    float voltage = ads.readADC(voltagePin) * (adcMaxVoltage / maxADCValue);
    voltage *= voltageDividerRatio;

    float current = ads.readADC(currentPin) * (adcMaxVoltage / maxADCValue);

    float rmsVoltage = voltage / sqrt(2);
    float rmsCurrent = current / sqrt(2);

    float power = rmsVoltage * rmsCurrent;

    float realPower = realPowerSum / NUM_SAMPLES;
    float apparentPower = voltageRMS * currentRMS;
    float powerFactor = realPower / apparentPower;

    float energyWh = (power * samplingInterval) / 3600.0;
    float energyJ = energyWh * 3600.0;

    totalEnergyWh += energyWh;
    totalEnergyJ += energyJ;

    Serial.print("RMS Voltage: ");
    Serial.print(rmsVoltage, 2);
    Serial.print(" V, RMS Current: ");
    Serial.print(rmsCurrent, 2);
    Serial.print(" A, Power: ");
    Serial.print(power, 2);
    Serial.print(" W, Power Factor: ");
    Serial.print(powerFactor, 2);
    Serial.print(", Total Energy: ");
    Serial.print(totalEnergyWh, 2);
    Serial.print(" Wh, ");
    Serial.print(totalEnergyJ, 2);
    Serial.println(" J");
}

• Sampling: Voltage is read from A0 and current from A1, typically with many samples averaged.
• Offset Adjustment: For AC sensing, the ADC mid-point (512) is used to remove offset.
• RMS Calculation: RMS values are computed by summing squared samples and taking the square root.
• Power:
  • Real Power: Average of instantaneous V·I
  • Apparent Power: RMS Voltage × RMS Current
  • Power Factor: Real / Apparent

• Voltage & Current Scaling: ADC readings are mapped back to real-world voltage and current.
• Power Computation: RMS voltage × RMS current yields total power.
• Energy Accumulation: Energy is added each interval in Wh, kWh, and Joules.