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 ...

Here is a tested Arduino project that uses 3 sensor probes as water level indicator with 3 leds and one LCD display + a simple controller that turns on a motor when the water has reached the desired ...

The project is equipped with a DHT11 sensor to read the room's temperature and an LCD to display this temperature reading and the speed the motor is currently running at.

The Arduino compatible Pax Instruments T400 Temperature Datalogger is now available to purchase priced at $175 from Adafruit. If you liked this you might also be interested in building an Arduino ...