const byte interruptPin = 4;
void ICACHE_RAM_ATTR count();
void setup() {
  Serial.begin(115200);

  // Set up our digital pin as an interrupt
  pinMode(interruptPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(interruptPin), count, RISING);
}

void loop() {

}

void count() {
  volatile float rainrate = 3;
  volatile float rate;
  volatile float total;

  rate = rainrate * 0.1; 
  Serial.println(rate);

everytime it tips, it returns 0.3, how to add the previous value(0.3) to a new tip to make it 0.6 and save it into a variable.

thanks!

const byte interruptPin = 4;
void ICACHE_RAM_ATTR count();
void setup() {
  Serial.begin(115200);

  // Set up our digital pin as an interrupt
  pinMode(interruptPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(interruptPin), count, RISING);
}

void loop() {

}

void count() {
  volatile float rainrate = 3;
  volatile float rate;
  volatile float total;

  rate = rainrate * 0.1; 
  Serial.println(rate);

Every time it tips, it returns 0.3. How do I add the previous value(0.3) to a new tip, to make it 0.6, and save it into a variable.

Thanks!