#include <DHT.h> 
DHT sensor1(PA0, DHT22);

#define but PA4

static HardwareTimer mytimer = HardwareTimer(TIM3);
int i=0;
double f=32000;

float humidity;
float temperature;
boolean state=true;

void ISR(){
  state =! state;
    
}

void setup(){
  pinMode(but, INPUT);
  mytimer.attachInterrupt(digitalPinToInterrupt(but)ISR,RISING);
  mytimer.setOverflow (500);
  mytimer.resume();
}

void loop() {
      humidity = sensor1.readHumidity();
      temperature = sensor1.readTemperature();
      if (state=true){
        Serial.println(humidity);
      }else{
        Serial.println(temerature);
      }
}