Arduino: Digital clock with temperature measurement

The project uses an Arduino and the following components:

• RTC_DS1307 - Real-time clock module (RTClib library),
• TM1637Display - 4-digit display with backlight - controlled by CLK and DIO,
• DHT11 - Temperature and humidity sensor (connected to pin 9),
• DS18B20 - digital thermometer (sensors connected to OneWire bus on pin 3).

• RTClib.h - RTC clock support,
• Arduino.h - Arduino platform base functions,
• TM1637Display.h - 4-digit display control,
• DHT.h - DHT11 sensor control,
• OneWire.h i DallasTemperature.h - DS18B20 support,
• SPI.h, Wire.h - communication libraries (Wire™ used by RTC).

• CLK 6, DIO 4 - TM1637 display pins,
• DHTPIN 9, DHTTYPE DHT11 - DHT11 sensor configuration,
• ONE_WIRE_BUS 3 - bus for DS18B20.
• Objects:
  • RTC_DS1307 rtc;
  • TM1637Display display(CLK, DIO);
  • DHT dht(DHTPIN, DHTTYPE);
  • OneWire oneWire(ONE_WIRE_BUS);
  • DallasTemperature sensors(&oneWire);

1. rtc.begin() - starts the RTC clock,
2. sensors.begin() - initialises the DS18B20,
3. sets the brightness of the display (setBrightness) and shows “8888” as a test,
4. Initialises the serial port (Serial.begin) - to debug measurements,
5. dht.begin() - initialises the DHT11 sensor.

1. sensors.requestTemperatures() i getTempCByIndex(0) - DS18B20 temperature reading,
2. conversion to int - rounding (round),
3. rtc.now() - gets the current time; extracts the hour and minute,
4. read from DHT11: readHumidity() i readTemperature(),
5. Formatting the time as a 4-digit string (e.g. “0835”),
6. Converting to a number (toInt()) and displaying sequentially:
   • hour and minute,
   • temperature from DHT11 (°C),
   • humidity from DHT11 (%),
   • temperature from DS18B20 (total value),

Each reading - 2 seconds.

• RTClib - Support for DS1307/DS3231 RTC modules,
• TM1637Display - showing digits on 4-segment display with decimal point,
• DHT - humidity and temperature reading from the DHT11,
• OneWire + DallasTemperature - support of even multiple 1-wire thermometers,
• SPI i Wire - required by some of the above (e.g. RTC).

1. At start-up, the display shows “8888” - operation test of all segments,
2. Then it displays the time (hhmm),
3. Then sequentially every 2 seconds:
   • temperature DHT11 (e.g. “23.5” → “23.5°C”),
   • DHT11 humidity (e.g. “45.2” → “45.2%”),
   • DS18B20 temperature (e.g. “24” → 24°C).

• Addition of buttons for time setting,
• Data registration to EEPROM or SD card,
• Extension of the interface - e.g. menu selection of displayed values,
• Use of DS3231 for greater RTC accuracy.

The device is a 'digital' type clock with temperature and humidity measurement, visualising the values on a TM1637 display. It uses three different sensors and simple Arduino libraries, making the project a great example of hardware and software integration in a single system.

Video recorded a long time ago and in English, so please be understanding ;)

#include ''RTClib.h''
#include <Arduino.h>
#include <TM1637Display.h>
#include ''DHT.h''
#include <OneWire.h>
#include <DallasTemperature.h>
#include <SPI.h>
#include <Wire.h>
 
#define CLK 6
#define DIO 4
#define DHTPIN 9
#define DHTTYPE DHT11
 
#define ONE_WIRE_BUS 3
 
RTC_DS1307 rtc;
 
TM1637Display display(CLK, DIO);
 
DHT dht(DHTPIN, DHTTYPE);
 
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
 
void setup() {
 
  rtc.begin();
  sensors.begin();
 
  display.setBrightness(0x0f);
  display.showNumberDecEx(8888,0b01000000, false);
  delay(3000);
  display.clear();
  display.setBrightness(3);
  Serial.begin(57600);
  dht.begin();
}
 
void loop() {
  sensors.requestTemperatures();
  float tempC = sensors.getTempCByIndex(0);
  int tempINT = round(tempC);
  DateTime now = rtc.now();
  int Minute = now.minute();
  int Hour = now.hour();
  String strMinute;
  String strHour;
  float h = dht.readHumidity();
  float t = dht.readTemperature();
 
  if(Hour < 10)
    {strHour = ''0'' + String(Hour);}
  else if(Hour >= 10)
    {strHour = String(Hour);}
  else if(Hour == 0)
    {strHour = ''00'';}
 
  if(Minute < 10)
    {strMinute = ''0'' + String(Minute);}
  else if(Minute >= 10)
    {strMinute = String(Minute);}
  else if(Minute == 0)
    {strMinute = ''00'';}
 
 
 
  String Time;
  Time += strHour;
  Time += strMinute;
 
  if(Time == ''0''){
    Time = ''0000'';
  }
 
  Serial.println(tempC);
  Serial.println(tempINT);
  int numTime = Time.toInt();
  display.clear();
  display.showNumberDecEx(numTime,0b01000000, true);
  delay(2000);
  display.clear();
  display.showNumberDec(t,false,2,1);
  delay(2000);
  display.clear();
  display.showNumberDec(h,false,2,1);
  delay(2000);
  display.clear();
  display.showNumberDec(tempINT,false,2,1);
  delay(2000);
 
 
}