A high precision Arduino compatible frequency counter

The concept of this board is to build an open, very versatile frequency meter circuit that can be used to measure a wide variety of signals. It is designed to be customizable in every possible way.

Freq_LF_HF final prototype

Freq_LF_HF final prototype

Freq_LF_HF v1.0 board uses the famous AVR microcontroller Atmega328p-AU. This is not the newest ATMEL model but this chip is standard on Arduino UNO v3.0 board. It is a powerfull microcontroller and very small (TQFP-32). This gives the opportunity for users to benefit from the Arduino community support and the many software libraries. The firmware uses a couple of the wonderfull functionnalities of this chip, namely the 16 bits timer, interrupts and comparator to an external precision voltage reference.

Proof of concept was done by breadboarding and using a standalone UNO board. Followed 3 prototypes to choose between a couple of topologies and eventually fine-tune the board. It is now time to produce a first batch of at least 100 boards, by a professional assembly company, and using the latest technologies available. This digital frequency counter will feature:

Very wideband, It can measure frequencies from less then 5 Hz to above 70 MHz, thanks to a unique hardware and software architecture. Low frequency signals (LF), high frequency signals (HF) and very high frequency signals (VHF) are treated separately to get a very good precision over the bandwidth.

Signal amplitude ranges from 0.5 volts to 10 volts.

High precision:

  • Accuracy: 0.005%
  • Precision: 0.005%
  • Resolution:  frequency < 10 KHz: 4 digits,  frequency >= 10 KHz: 5 digits

Measuring: 5 Hz, 50 Hz, 440.1 Hz, 1.001 KHz, 32.768 KHz, 450 KHz, 4 MHz, 80 Mhz.

 

Measuring a 4 MHz signal.

 

Easy to use

  • Uses a standard LCD 16 characters, one line display for clear presentation of the frequency. LCD display can be disassembled from the board and mounted on a box as needed.
  • Can be powered using a 9V ac/dc converter or directly to PCB pins or by a 9V battery with the adapter included in the package. It tolerates voltages between 7.5 and 12 volts. The power source is protected by a polyswitch fuse.
  • It is protected against over voltage and under voltage power conditions. The board will show error messages.
  • Signal can be fed to the board using a BNC connector or PCB headers.
  • Input impedance is 1 MOhm.
  • Signal input is ESD protected by a TVS diode up to 200 W / 3A peak power discharges (Caution, this is about electrostatic discharges only! Users should never try to measure signals above 30 volts peak-to-peak!).
  • It has a reset button to reset the AVR.
  • A menu button to choose parameter values:
    • Frequency band: LF/HF (automatic low frequency or high frequency computing), LF, HF and VHF (above 1 MHz).
    • Calibration.
  • A standby / energy economy mode is engaged when the board does not measure any frequency for 5 minutes or on demand.
  • This is a compact board (approximately 82*60 mm).
Sharing frequency values between Freq_LF_HF and Arduino Nano over I2C@100Khz

Application example: sharing frequency values between Freq_LF_HF and Arduino Nano over I2C@100KHz

 

Standard Arduino

Programming in 3 lines

  • Allows to tweak the software. Since it is based on standard Arduino libraries and coding you can tweak it and even change the functionality of the board. The library is open source under creative commons licence Licence Creative Commons
  • Uses SPI port for programming through a SPI programmer. It does not require a bootloader but the user can load one. This port can also be used to interface with another peripheral.
  • Has serial port (USART) available for serial communication with a PC through a USB-to-serial adapter or to interface with another peripheral. It can also be used to program the board.
  • Has I2C port available to interface with many integrated components or establish complex communication between Arduino boards.

 

Follow industrialization

This is a real kickstarter project, not selling of an existing product. It is an original design, never published anywhere else! It will be tested as a fully functionnal prototype, than an industrialized prototype before batch production. Boards will be under technical and functional tests before delivery.

 

Testing an 80 Mhz ocxo.

Testing an 80 MHz ocxo.

 

A sustainable project

I live nearby the sea and I am sick of seeing the dirty beaches and the dying sea. Any industrial process, particularly in high technology, involves the use of many chemicals, precious materials, energy, transportation etc…  In coherence with one of our goals, for this project I will make a contribution to The Ocean Cleanup. Also the program of the board includes a “standby mode” or “energy economy mode” that shuts down the microcontroller , the LCD screen and the amplifier circuits after an inactivity lap with respect to EU directives, or on demand.

 

International

 

Offers!

 

Enter the contest to Win your frequency counter board!

 

Arduino compatible frequency counter project log

Technical specifications here above are design specifications. Manufactured boards will be somewhat different in appearance and performance.

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