Temphum

//Temperature and Humidity Sensor
#include "DHT.h"
#include <Arduino.h>
#include <U8x8lib.h>
#define DHTPIN 3 // what pin we're connected to
#define DHTTYPE DHT11 // DHT 11
#define CELSIUS 0
#define FAHRENHEIT 1
#define BUTTON_INTERVAL 100

const int buttonPin = 2;
int buttonState = 0;
int tempUnit = CELSIUS;

DHT dht(DHTPIN, DHTTYPE);
U8X8_SSD1306_128X64_ALT0_HW_I2C u8x8(/* reset=*/ U8X8_PIN_NONE);

void setup(void) {
   Serial.begin(9600);
   Serial.println("DHTxx test!");
   dht.begin();
   u8x8.begin();
   u8x8.setPowerSave(0);
   u8x8.setFlipMode(1);
   attachInterrupt(digitalPinToInterrupt(buttonPin), changeUnit, RISING);
}

void print_temp(void) {
   float temp = dht.readTemperature();
   u8x8.setCursor(0, 33);
   u8x8.print("Temp:");

   if (tempUnit == CELSIUS)
   {
     u8x8.print(temp);
     u8x8.print("C");
   }
   else
   {
     u8x8.print(temp * 1.8 + 32);
     u8x8.print("F");
   }
}

void changeUnit(void) {
    static unsigned long last_press = 0;
    static unsigned long timer;

    timer = millis();

    if (timer - last_press > BUTTON_INTERVAL)
    {
      if (tempUnit == CELSIUS)
        tempUnit = FAHRENHEIT;
      else
        tempUnit = CELSIUS;

      last_press = millis();
    }
}

void loop(void) {
     buttonState = digitalRead(buttonPin);
     float humi;
     humi = dht.readHumidity();
     u8x8.setFont(u8x8_font_chroma48medium8_r);
     print_temp();
     u8x8.setCursor(0,50);
     u8x8.print("Humidity:");
     u8x8.print(humi);
     u8x8.print("%");
     u8x8.refreshDisplay();
     delay(200);
}