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 PIC 18F4550 400MHZ LCD Frequency Counter


 FC3-HF: 50MHZ PIC18F4550 Counter with Bargraph.
A Simple PIC 18F4550 USB Powered Frequency Counter with Bar-Graph
Project by:

Antonio Alfinito / I2TZK

Frank Dziurda / K7SFN 

Dinesh Gajjar / VU2FD

This project is now revised to: FC3-SK-0317: Please visit


Frequency Counter project detailed here is based on PIC18F4550 

There are many PIC based frequency counters out there but this one will stand apart from others. 


1. Its USB Powered

2. Simple One Chip 18F4550 Project

3. Count frequency to 50MHZ (Maximum and PIC Specific)

4. 2 x 16 LCD Display

5. Signal Level Indication (Bar Graph)

6. Small enough to carry around with your laptop

7. Frequency "off-sets" set by PC program.

8. Free PIC Firmware & PC WIN Software by Tony/I2TZK

Counter is designed on a double sided PTH Board and works on USB power. There is an option to apply external +5V for those who wish to power this counter from their own +5V source.

Project is designed and developed for science students and Radio Amateurs, looking for economical frequency counter for their hobby work. It may be a perfect frequency display for old radios too. (Any IF Offsets OK)

Keeping this in view, expensive chip like AD8307 for accurate measurement of signal level is avoided and instead we have used simple diode detectors to display signal level on second line of LCD as a bargraph.

An advanced version of this Frequency Counter is also availabe as FC3

FC3 counters uses AD8307 to measure RF level very accurately and measure in DBm, Vpp or RMS. 

But on this economical counter, we get an indication of signal presence by way of a bargraph.

Counter works with PC and also as a Stand-alone. Usually, you configure this counter using a PC software, enter IF Offsets, adjust back-light and if required, calibrate with an accurate frequency source and then use as a standalone unit.

Completed Frequency Counter: FC3-HF

Click the picture to enlarge


Bar Graph of received signal:

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Frequency Counter, LCD Removed:

Click the picture to enlarge


 Schematic & Documents:
FC3-SK 50MHZ Frequency Counter Document
Schematic & Parts List  
FC3-SK Schematic   JPG
 Datasheets and other files
Make your own PCBs  
 Firmware and PC Config Software
Programming Hex 18F4550
FC3 PC Software by Tony / I2TZK
 Visit I2TZK Web Site
 Buy On-Line

Please visit active project/Kits: FC3-SK-0317



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