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Frequency Counter DIY Kit Module

Frequency Counter DIY Kit Module


An easy to build Open Source DIY kit of Frequency Counter based on PIC16F628A microcontroller. Economy package intended to measure frequency input up to 5MHz. Full extended package includes MB506 prescaler that allows to measure HF and VHF up to 250MHz.


Technical specification for Economy Package 5MHz Counter:

  • Low frequency input "LF" 10Hz - 5MHz
  • Sampling 1000ms or 100ms
  • Resolution for 1000ms - 1Hz
  • Resolution for 100ms - 80Hz
  • Input impedance for "LF" 1K ohm
  • Accuracy 1%
  • Power consumption 5V 10mA
  • UPC Number: 635346988660
  • SKU: RH-K-FC-1-5


Technical specification for Extended Package 250MHz Counter:

  • Low frequency input "LF" 10Hz - 5MHz
  • High frequency input "HF" 5MHz - 250MHz
  • Prescaler 1/64
  • Sampling 1000ms or 100ms
  • Resolution for 1000ms - 1Hz
  • Resolution for 100ms - 80Hz
  • Input impedance for "LF" 1K ohm
  • Input impedance for "HF" 50 ohm
  • Accuracy 1%
  • Power consumption 5V 30mA
  • UPC Number: 634654895738
  • SKU: RH-K-FC-1-250


Frequency counter kit can be purchased in Economy or extended Full package. Select Full package if you need prescaler to measure radio frequency signals.

The kit is easy to solder except one SMD socket for mini USB. The socket can be soldered with tin solder iron and desoldering braid to remove exceed solder between contacts. We also offer service to install this SMT part for you, just select "Solder USB Socket for me" option before you add it to the cart.

Take note, the kit works with standard HD44780 LCD 16x2. 

The LCD Module in not included in the default packages, but you can add it by selecting "Add LCD Module" option before you put the kit into your shopping cart.

If you select "White on Blue" color LCD then it requrie 100 ohm backlight resistor instead of 1K resistor. We include 100 ohm resistor for Blue Color LCD. Be sure you install 1K ohm for Green or 100 Ohm for Blue color LCD!

The electrical circuit based on PIC16F628A microprocessor and 1/64 configured MB506 Prescaler. For better accuracy and stability, the MCU clocked by active 4.000MHz oscillator.

Prescaler block has about 50 ohm input impedance and two protection diodes for high frequency. MB506 divide input frequency by 64 and then trigger the MCU to count square wave signal. After the MCU complete count procedure, the processor will multiplies the number back by 64 to allow real frequency be displayed on LCD. In this way you can measure HF and VHF radio waves signals.

To measure signals under 10MHz, or audio frequency range, you can use "LF" input that drive input transistor amplifier stage directly. Be sure your signal has enough amplitude to trigger T2, usually its about 1V peak to peak signal.


MCU Software:

Microcontroller program written in mikrobasic compiler. The kit has open source code for education purpose. Because the code size is less than 2K you can use Mikroe Demo Basic Compiler for PIC to modify the program. The code provided as is with no technical support for its modifications. The controller sold pre-programmed and the software is compatible with both packages, economy and full.





Powering the kit:

Both packages comes with 5V LM78L05 regulator IC. You can use 7.2V lithium battery, power supply DC 7V-12V 100mA output or computer USB jack. If you use prescaler then 9V battery its not recommended because prescaler IC consumes about 20mA current thats overload 9V battery.


Frequency tests with MB506 and different Active Oscillators:



Reading MHz   


F1100E 16MHz



OK! Within ppm limits

MX045 50MHz



OK! Within ppm limits

ACHL 100.0-ER 100MHz



500Hz out of ppm limit!

KSS CXO-046B 125MHz



OK! Within ppm limits


What is ppm? Part Per Million (ppm) is the unit to express frequency stability for 1MHz. For example, if you have declared 100ppm for 16MHz its mean the expected frequency stability range will be 100Hz * 16 = 1600Hz, or 16MHz + -1600Hz.

When you are buying this product you are agree that you have certain skills and knowledge to solder it by yourself. We are not responsible if you damage the PCB or other kit's parts due to wrong assembling or handing. All components have part name and part number so you can easily place in on the PCB regarding the circuit and the silkscreen.

No matter what, if you have any questions about assembling or using the device, we can provide you a technical support. If you are in doubt about something is always better to ask us before any action.


Video showing switching frequency ranges with DDS generator and the kit LF and HF inputs response. It demonstrate the actual measuring accuracy and software resolution. Recommended ranges for LF is 10Hz - 5MHz; for HF is 5 MHz - 250 MHz.

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