100MHz frequency counter with LCD display

Update November 26, 2015:
I made a full project with preamp/signal conditioning and power supply with soft on/of switch. It is published here.


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This is the same as the previous frequency counter but the output is on the 16x2 LCD display.
For more details about how it work look here: http://diyfan.blogspot.bg/2015/08/100mhz-frequency-counter.html

100MHz frequency counter

Couple of weeks ago I purchased from eBay one of these amazingly cheap an useful modules with MAX7219 LED driver and 8 digit LED display. It is ideal for frequency counter project. The problem was the absence of library for PIC microcontrolers. Luckily, I found a great library for Arduino and I reworked it to be compatible with PIC. The schematic of the frequency counter is actually almost the same as the previous . It uses PIC16F628A microcontroller with external 32.768kHz watch crystal attached to Timer1 to generate 1 second time base. Measured signal is fed to pin3 (RA4) which is counted by Timer0.

Audio oscillator with frequency counter 2

My last project is not completely new. In fact, the oscillator is made from the same schematic as in one of my previous projects and only the frequency counter is made with different schematic.

Frequency counter with PIC16F628A

Some time ago I made an audio oscillator with frequency counter which worked very well, but I sold it, and now I am making a new one. The oscillator itself will be mostly the same and when I finish the whole project there will be a separate article. Here I will show the frequency counter module I made for the project.

Audio Oscillator with Frequency Counter

I am continuing to add DIY equipment to my home workshop. Audio oscillator is a very useful tool that is needed when we test audio projects. I already have a similar tool but it is just an oscillator without a frequency counter. I decided to use the schematic described in this page:  http://www.redcircuits.com/Page82.htm.
It is a standard Wien Bridge oscillator but uses a very interesting way to stabilize amplitude - optocouple of photoresistor and LED.