Frequency Counter library for atmega32u4

Posted by KarlP on 23 March, 2010 Leave a comment (3) Go to comments

The guys at KHM in Cologne cooked up a very handy Frequency Counter library for arduino. Seeing as my humidity sensor is based around the HCH1000, basically a variable capacitor, one simple way to measure the humidity is to use the sensor in an oscillator, and use the output frequency as an indicator of the humidity. (I really need to get around to writing that up properly, it’s in progress, I promise)

Anyway, I have more boards than just an Arduino, and I also use mostly raw C. So I’ve update the library to work with either the atmega 168 or 328 on arduino boards, but also with the atmega32u4 found on PJRC’s nifty little Teensy boards

You can get the code over on github (You need FreqCounter.c and .h)

avr

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3 Comments.

Marco Mauro 9 May, 2013 at 12:28 pm

Hi KarlP,

I’ve arduino micro with ATmega32u4. I get your library and upload this sketch

#include  
void setup(){
 Serial.begin(57600);
 pinMode(x, INPUT);  // what pin ?
}
long int frq
void loop(){
 f_comp= 8;
 FreqCounter__start(f_comp, 100);
 frq = blockingRead(f_comp, 100);
 Serial.println(frq);
 delay(50);
}

what is the frequency input pin on arduino micro board ? I’ve tried all digital pin but I’m not able to read frequency but I might be wrong.
Do you have any suggestion ? thank you

KarlP 9 May, 2013 at 6:36 pm

Firstly, this is not an arduino library. You need to use the pin connected to Timer1 input. “T1” it is often called. But again, this is nto an arduino library.
miskol 25 May, 2020 at 8:40 am

oh now i understand why i cant compile it, its not an arduino library…

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