Arduino project · Temperature and climate · Easy
Digital Thermometer with LM35 and LCD
An LM35 sensor measures the temperature and the LCD shows it.
What you will learn
- How an analog temperature sensor works
- How to show a reading on an LCD
- How to wire an I2C display
How it works
The LM35 gives 10 mV per degree Celsius. The Arduino reads the voltage on an analog pin and converts it to degrees. The LCD block shows the reading on line 2 and updates 3 times per second.
Try this next
- Add an alarm above 40 degrees.
- Show the temperature in Fahrenheit.
- Add a fan for cooling.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Parts: sensors and actuators (tap to show or hide)
Try the inputs (virtual sensors)
Pins (you can change them)
| Part | Arduino pin (change it here) | How to wire it |
|---|
Every wire, one by one
Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.
| # | Colour | From (part and leg) | To |
|---|
Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.
Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.
| # | Item | Qty | Search term | Buy / compare |
|---|
The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.
In the real world
A thermometer on the wall
Move the temperature slider. The mercury in the real thermometer follows.
Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.
- Temperature sensor = the room temperature