Wireless Frequency Meter using Arduino

The Wireless Frequency Meter project uses an Arduino Uno to measure and display the frequency of an incoming AC signal, transmitting the data wirelessly to a remote receiver unit. At the input stage, the circuit safely conditions the incoming AC signal using 1N4007 rectifier diodes and an MCT2E opto-coupler IC. The opto-coupler provides electrical isolation between the high-voltage or external test domain and the low-voltage Arduino processing logic, while converting the AC waveform into a clean series of digital pulses corresponding to the signal's zero-crossings. The Arduino Uno processes these incoming pulses by counting transitions over a set time window to calculate the frequency, which spans from 50Hz to 3kHz. Once calculated, the frequency data is relayed using a 434MHz RF transmitter module. A matching 434MHz receiver module captures the transmitted data frame on the remote end. Finally, the receiving microcontroller processes the packet and drives a 16x2 character LCD screen to present the real-time frequency measurement to the user. A stable power supply ensures reliable operation across both the sensing-transmitting node and the receiving display node.