Electronics > Projects, Designs, and Technical Stuff
Frequency counter
bd139:
If you want a relatively simple one I built one of these a few years back because there was nothing on ebay and I had the bits lying around: http://www.hamradio.in/circuits/freq_counter_lcd.php
It worked but I had to futz with the LCD code as I only had a 2x16 display handy. No prizes for construction here as it was a rush job just to solve a couple of problems on a radio. It has computation ability so you can add/remove IF frequencies with it which was rather neat.
Edit: don't use polyester caps on the input like I did. That was a stupid idea :-DD ... worked up to about 45MHz I think. It got recycled for parts since.
7 seg displays are harder to work with IMHO. Best bet is a large character 8x1 LCD module these days with backlight
Theboel:
what about read this thread and made as much as modification You like without to much worry about choose the right hardware.
https://www.eevblog.com/forum/projects/ten-dollar-pic-100khz-2-4ghz-frequency-counter/
HB9EVI:
I built longer time ago one based on Atmega328 with a OCXO running @ 20MHz and 74HC variable software presetable divider ratios on the input, but with 8 7seg multiplexed by a MCP23017
I used it now for quite a while but I'm actually working on a reciprocal counter based on a STM32F429 running @ 180MHz locked either by a OCXO or GPSDO; no more 7seg but a 3,5" TFT
Ian.M:
7 segment displays with up to eight digits are pretty easy to work with if you use a MAX7219 LED driver. 8 digit MAX7219 LED display modules are cheap and readily available from many suppliers including EBAY.
If you've done any low level programming on 8 bit computers, or for any MCU, and you can program in 'C', then getting into Microchip PICs is pretty easy. I no longer recommend the PICkit 2 - its just too obsolete and limits your choice of chips severely, especially if you stick to the subset that it can both program and debug. A PICkit 3 is a much better choice. The PICkit 4 is still a bit too new and flaky - its more or less where the PICkit 3 was when Dave made his famous bashing video. To get started, all you need is MPLAB + XC8 (both free downloads), a PICkit 3 programmmer (or reputable clone), six short Dupont pin to pin jumper wires to hook up the programmer, a solderless breadboard and a suitable PIC. You'll probably also need an 100nF ceramic cap for decoupling, (2x for 40 pin PICs), a 10K resistor to pullup the PIC's /MCLR (reset) pin, and a LED + a 330R resistor to hang off an I/O pin for your first 'Hello World' LED blinkie test program.
If you haven't done *ANY* MCU development before, you may do better to start off with Arduino rather than Microchip PICs. At least you can dip your toes in the water really cheaply and find out if you have any aptitude for 'C' programming. Unfortunately the AVR microcontroller used in entry level Arduinos doesn't support anything near as high an external counter/timer clock frequency as PICs do, and also genuine Arduinos and many clones use a rather inaccurate 16MHz ceramic resonator for the MCU clock so you cant build a very good frequency counter easily with one, but it would do to get you started with a 'proof of concept' project build.
If you cant program in 'C', you need to learn!
HB9EVI:
Sure, today the MAX7219 is readily available - wasn't the case at that time I built that counter...
My advise'd be to start AVR on the direct way, without arduino hard/software; especially for a counter fast routines are a must, so all these bitWrite() routines should be avoided; even some inline assembler can be thought about for a counter.
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