The LM35 temperature sensor and red led are powered with 5V from the Arduino board. How does the circuit works? As you can see in the sketch on the first line I included the LiquidCrystal library ...

Now it is clear, a MCP9700A temperature sensor connected to the Arduino analog input pin A1 is used to measure temperature. The Arduino sketch for the experiment handles the inputted data and displays ...

If you want to make your own system for doing so, Instructables user ICStation shows off how to use an Arduino to do it. The system here monitors temperature, humidity, and smoke levels and alerts ...

The Anavi Thermometer Development board is fully compatible with the Arduino IDE, ... It comes with a built-in DHT22/AM2302 temperature and humidity sensor and has slots for a mini OLED ...