reset value sensor

first, im sorry if englsh bad

i use arduino meg+reed switch sensor count rainfall.. resolution 0.2 mm.. use code :

quote

const int reed = 4;              //output reed switch di pin 9
int val = 0;                    //nilai arus pada reed switch
int old_val = 0;                //nilai dari reed switch yang lama
float reedcount = 0;              //this variable hold count of switching


void setup(){

 serial.begin(9600);
 pinmode (reed, input_pullup); //mengaktivasi pull pada internal resistor

}


void loop(){

 val = digitalread(reed);      //baca status pada reed switch


 if ((val == low) && (old_val == high)){    //cek jika terjadi perubahan status pada reed switch

   delay(10);                   // delay put in deal "bouncing" in switch.

   reedcount = reedcount + 0.2;   //add 1 count of bucket tips
   old_val = val;              //make old value equal current value

   serial.print("hujan = ");
   serial.print (reedcount);  //output count serial monitor
   serial.println("  mm");
   
 }


 else {

   old_val = val;              //if status hasn't changed nothing

 }

}

i count rainfall every 3 hours , display serial monitor.. 00:00 , 03:00 , .......etc
after 3 hours, value of sensor reset,back 0 , start count.

and @ 24:00/00:00 ,, arduino calculate sensor value 24 hours...

can me.?? function should use..??

code: [select]

float reedcount = 0;   
are expecting reed switch open , close fractional number of times?

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