Arduino Projects for Amateur Radio

CHAPTER 15

A Simple Frequency Counter

In this chapter we construct a simple device for measuring frequency called a frequency counter. It uses the timer function in the Arduino’s Atmel processor and measures frequencies from the audio range to a little over 6 MHz. It is constructed on a single Arduino R3 prototyping shield and includes an LCD to readout the frequency. The counter is surprisingly accurate and can easily be calibrated with a known accurate frequency source. The chapter ends with a discussion of how to use the frequency counter with a typical QRP radio that lacks a frequency readout. We use the Arduino Frequency Counter to measure the Variable Frequency Oscillator or “VFO” frequency and then display the corresponding receive or ...