DIY Simple Arduino Frequency Meter Up to 6.5MHz

Today I will show you how to build simple Frequency counter capable to mmeasure frequences of reactangular, sine or triangular signals up to 6.5 MHz

The device presented in the video is a frequency meter made using an Arduino Nano microcontroller. It can measure the frequency of signals with rectangular, sinusoidal and triangular shapes.

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Its measurement range is from a few hertz to 6.5 Megahertz. Three measurement time intervals are also available - 0.1, 1 and 10 seconds. If we measure only rectangular signals, then there is no need for a shaping amplifier and the signal is fed directly to the digital pin 5 from Arduino. The code is very simple thanks to the "FreqCount" library which you can also download below. The device is very simple and consists of several components:

- Arduino Nano microcontroller

- Shaping amplifier board

- LCD display

- Input signal shape selector

- Input JACK

- and Time interval switch : we can choose three intervals 0.1 -1 -and 10 seconds .

As you can see in the video, the instrument is very precise in the whole range, and we can also calibrate the frequency meter with the simple procedure described below:

In the Arduino libraries folder find the FreqCount library, in the FreqCount.cpp file find the lines: #if defined (TIMER_USE_TIMER2) && F_CPU == 12000000L float correct = count_output * 0.996155; and replace them with: #if defined (TIMER_USE_TIMER2) && F_CPU == 16000000L float correct = count_output * 1.000000; where 1.000000 is your correction factor, the correction must be carried out by applying 1 MHz to the input of the frequency meter. After changing the file, upload a new sketch to the Arduino board.

Finally, the frequency meter is built into a suitable plastic box and is another useful instrument in the electronic laboratory.