Build a Grid Frequency Deviation Alarm with Arduino Uno – Real-Time AC Mains Monitoring Kit

Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.

In India, AC grid frequency swings between 49.5 Hz and 50.2 Hz, and a sudden deviation beyond 0.5 Hz can indicate overloads or imminent generator tripping. This kit puts you in the role of a power systems engineer—you’ll build a device that uses zero-crossing detection on the ZMPT101B transformer to measure frequency, then triggers an audible and visual alarm the moment it drifts outside safe limits.

What You'll Build

You’ll wire a complete monitoring station around an Arduino Uno, reading AC voltage through the ZMPT101B, capturing precise zero-crossing timestamps with interrupts, and computing frequency in real time. The 0.96-inch OLED displays the current frequency, while the active buzzer and on-screen icon fire whenever the frequency deviates beyond ±0.5 Hz from the set nominal (50 Hz). All events are logged with time stamps from the DS3231 RTC onto a microSD card, giving you a permanent record of grid stability for lab reports or hackathon demonstrations.

ZMPT101B AC zero crossing measures grid frequency. Alarm triggers on deviation beyond 0.5Hz from nominal.

What's in this kit

• Arduino Uno R3
• ZMPT101B
• DS3231 RTC
• MicroSD Module
• Active Buzzer
• 0.96in OLED
• 10kΩ Resistors x5
• 100nF Caps x5
• 400-pt Breadboard
• M-M Wires x20
• 9V Battery Snap