Arduino AC Power Meter with LCD Display & Automatic Voltage Protection

Take control of your energy management and protect your expensive appliances with our Smart AC Power Meter & Protection Kit. Designed for makers, solar enthusiasts, and smart-home hobbyists, this comprehensive DIY module offers real-time electrical parameter tracking alongside intelligent automated circuit-breaking capabilities. Advanced Monitoring Meets Automated Safety At the heart of the system is an Arduino-compatible architecture running optimized EmonLib firmware. The device continuously samples incoming AC mains to compute precise RMS voltage and current. Instead of just showing you the numbers, it acts as an active gatekeeper: if your mains voltage drops below 190V or spikes above 250V, the onboard heavy-duty relay instantly cuts power to the load, displaying a “CUT” status warning on the screen. Once grid conditions stabilize, it automatically restores power (“OK” status). Data Persistence & Smart UI Never lose track of your utility metrics. The firmware features an automated EEPROM writing cycle that backs up your cumulative energy usage (kWh) to non-volatile memory every 5 seconds. If the grid drops, your metrics remain intact. The data is neatly segmented across two automated display screens driven over a simple 2-wire I2C bus, minimizing wire clutter and maximizing readability. Hardware Requirements Arduino Nano or Uno ZMPT101B AC Voltage Transformer Module SCT-013-000 Current Transformer Sensor 16×2 LCD Display with I2C Adapter 5V 1-Channel Relay Module 5V DC Power Supply Module 2x 10k Ohm Resistors 1x 100 Ohm Burden Resistor 10uF Electrolytic Capacitor High-Voltage AC Socket with Plug AC Wires What’s Included in the Source Code Package? Dynamic Initialization Routine: Includes a 10-cycle warm-up delay loop to discard unstable initialization readings from AC sensors, preventing false relay tripping. Built-In Error Glitch Filtering: Software-level clipping clamps outlier readings (Voltage <90V or >300V; Current >10A) to zero, ensuring unmatched stability against line noise. Flexible Hardware Scaling: Easily upgrade from a 16×2 LCD to a 20×4 layout by simply uncommenting a single line in the initialization configuration. Target Audience & Use Cases Home Automation & Smart Grids: Monitor single-phase home appliances, PC setups, or server racks. Solar Inverter Monitoring: Keep tabs on DIY off-grid solar power systems and battery inverter outputs. Academic/Engineering Projects: An excellent source code template for turn-key electrical engineering capstone projects.