Published November 25, 2020 © GPL3+

Simple and easy weather station for indoor and outdoor

It's a simple weather station, that measures, internal and external temperature. It's made out of two components: indoor and outdoor.

BeginnerFull instructions provided1,530

Simple and easy weather station for indoor and outdoor

Things used in this project

Hardware components

Breadboard (generic)

DHT22 Temperature Sensor

Arduino Nano R3

433Mhz FS1000A transmitter

433Mhz RXB6 receiver

I2C OLED Display

Push Button normally open

Story

The idea was to combine the 433Mhz transmission with exchange of data between two devices so a simple weather station, that measures, internal and external temperature, was the right project for me.

It's made out of two components: an indoor receiver, and an outdoor transmitter. The transmission is managed at 433Mhz.

The components and the electrical diagram for both devices, are showed in the video.The receiver is very easy to use. to toggle between the external and internal temperature, you need to press the button for more than 3 seconds.

Code

#include <RCSwitch.h>

RCSwitch mySwitch = RCSwitch();
#include <DHT_U.h>

#define DHTPIN 3 
#define DHTTYPE    DHT22
DHT_Unified dht(DHTPIN, DHTTYPE);
uint32_t delayMS;

char temp[7];
char umid[7];

void setup() {
  
  // Transmitter is connected to Arduino Pin #10  
  mySwitch.enableTransmit(10);
  dht.begin();
  sensor_t sensor;
  dht.temperature().getSensor(&sensor);
  dht.humidity().getSensor(&sensor);
  delayMS = sensor.min_delay / 1000;
  
}

void loop() {
  delay(delayMS);
  // Get temperature event and print its value.
  sensors_event_t event;
  dht.temperature().getEvent(&event);
  if (isnan(event.temperature)) {
    Serial.println(F("Error reading temperature!"));
  }
  else {
    mySwitch.send(int(event.temperature*10),24);
  }
  delay(delayMS);
  // Get humidity event and print its value.
  dht.humidity().getEvent(&event);
  if (isnan(event.relative_humidity)) {
    Serial.println(F("Error reading humidity!"));
  }
  else {
    mySwitch.send(int(event.relative_humidity*10),25);
  }
  
  delay(2000);
}

/*
  Temperature receiver
  
  Displays temperature and Humidity internal and external 

  Carlo Stramaglia
  04-Feb-2024
  https://www.youtube.com/@CarloStramaglia

*/

#include <RCSwitch.h>
#include <DHT_U.h>
#include <U8glib.h>
#include <OneButton.h>

#define DHTPIN 3 
#define DHTTYPE    DHT22

RCSwitch mySwitch = RCSwitch();

U8GLIB_SSD1306_128X32 u8g(U8G_I2C_OPT_NONE);

DHT_Unified dht(DHTPIN, DHTTYPE);
uint32_t delayMS;

OneButton button(A1, true);

int tmp;
int checkavail=0;
int EstInt=0; // If 0 show internal while if 1 show external temperature
char temp[7];
char umid[7];
char tempe[7];
char umide[7];
//float flt = 2.75;

void setup() {
  Serial.begin(9600);
  mySwitch.enableReceive(0);  // Receiver on interrupt 0 => that is pin #2
  u8g.setColorIndex(1); 

//  button.attachClick(click);
  //attachInterrupt(digitalPinToInterrupt(5), checkTicks, CHANGE);
  button.attachLongPressStop(longPressStop);

  dht.begin();
  // Print temperature sensor details.
  sensor_t sensor;
  dht.temperature().getSensor(&sensor);
  Serial.println(F("------------------------------------"));
  Serial.println(F("Temperature Sensor"));
  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("°C"));
  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("°C"));
  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("°C"));
  Serial.println(F("------------------------------------"));
  // Print humidity sensor details.
  dht.humidity().getSensor(&sensor);
  Serial.println(F("Humidity Sensor"));
  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("%"));
  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("%"));
  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("%"));
  Serial.println(F("------------------------------------"));
  // Set delay between sensor readings based on sensor details.
  delayMS = sensor.min_delay / 2000;
}

void loop() {
  button.tick();
  if (mySwitch.available()) {
    tmp = mySwitch.getReceivedValue();
    if (mySwitch.getReceivedBitlength() == 24) {
      Serial.print("External Temperature: ");
      checkavail=0; // Reset the value
      dtostrf(float(tmp)/10, 2, 1, tempe);      
      Serial.print("Arriving: ");
      Serial.println(tmp);
      if (tmp < 100 and tmp >= 0)
        tempe[3]=byte(0x20);
        tempe[4]=byte(0x20);
      if (tmp < (-32758+100)) {
        tempe[3]=byte(0x20);
        tmp=(tmp+32768);
        dtostrf(float(tmp)/10, 2, 1, tempe);
        tempe[4] = tempe[3]; // Added 4 Feb 2024
        tempe[3] = tempe[2];
        tempe[2] = tempe[1];
        tempe[1] = tempe[0];
        tempe[0] = '-';  
        tempe[4]=byte(0x20);
      }
      if (tmp < 0 and tmp >= (-32758+100)) {
        tmp=(tmp+32768);
        dtostrf(float(tmp)/10, 2, 1, tempe);
        tempe[4] = tempe[3]; // Added 4 Feb 2024
        tempe[3] = tempe[2];
        tempe[2] = tempe[1];
        tempe[1] = tempe[0];
        tempe[0] = '-';  
        //tempe[4]=byte(0x20);
      }
      //tempe[4]=byte(0xb0);
      tempe[5]='C';
      tempe[6]='\0';
      Serial.println(tempe);
      }
    else {
      Serial.print("External Humidity: ");
      dtostrf(float(tmp)/10, 2, 1, umide);
      Serial.print(umide);
      Serial.println("%");
      umide[4]=' ';
      umide[5]='%';
      umide[6]='\0';
      }
    mySwitch.resetAvailable();
  }
  else {
    checkavail++;
    if (checkavail==100) {
      String notav = "NOT AV";
      strncpy(tempe, notav.c_str(), sizeof(tempe));
      tempe [sizeof(tempe) - 1] = 0;
      strncpy(umide, notav.c_str(), sizeof(umide));
      umide [sizeof(umide) - 1] = 0;
      checkavail=0;
    }
  }
  
  delay(delayMS);
  // Get temperature event and print its value.
  sensors_event_t event;
  dht.temperature().getEvent(&event);
  if (isnan(event.temperature)) {
    Serial.println(F("Error reading temperature!"));
  }
  else {
    Serial.print(F("Internal Temperature: "));
    Serial.print(event.temperature);
    Serial.println(F("°C"));
    dtostrf(event.temperature, 2, 1, temp);
    temp[4]=byte(0xb0);
    temp[5]='C';
    temp[6]='\0';
  }
  // Get humidity event and print its value.
  dht.humidity().getEvent(&event);
  if (isnan(event.relative_humidity)) {
    Serial.println(F("Error reading humidity!"));
  }
  else {
    Serial.print(F("Internal Humidity: "));
    Serial.print(event.relative_humidity);
    Serial.println(F("%"));
    dtostrf(event.relative_humidity, 2, 1, umid);
    umid[4]=' ';
    umid[5]='%';
    umid[6]='\0';
  }
  if (EstInt==0) {
    u8g.firstPage();  
    do {
      draw("In Temp:", 0, 14);
      draw(temp, 70, 14);
      draw("In Humi:", 0, 32);
      draw(umid, 70, 32);
    } while( u8g.nextPage() );
  }
  else {
    u8g.firstPage();  
    do {
      draw("Ex Temp:", 0, 14);
      draw(tempe, 70, 14);
      draw("Ex Humi:", 0, 32);
      draw(umide, 70, 32);
    } while( u8g.nextPage() );
  }
}

void longPressStop() {
  Serial.println("Button click.");
  u8g.firstPage();  
  do {
    draw("Please Wait...", 0, 23);
    } while( u8g.nextPage() );

  if (EstInt == 0)
    EstInt=1;
  else
    EstInt=0;
} 

void draw(char* parola, int posx, int posy) {
  // graphic commands to redraw the complete screen should be placed here  
  u8g.setFont(u8g_font_unifont);
  //u8g.setFont(u8g_font_osb21);
  u8g.drawStr( posx, posy, parola);
}