Digital Thermometer using Arduino | Circuit and Code

The Digital Thermometer project centers around an Arduino Uno microcontroller that coordinates input sensing and output display. At the heart of the sensing mechanism is the LM35 temperature sensor, an integrated circuit that outputs an analog voltage linearly proportional to the Celsius temperature. When connected to a 9V battery or power adapter, the Arduino Uno uses one of its analog-to-digital converter (ADC) pins to read the analog voltage signal generated by the LM35. A 4.7uF 25V electrolytic capacitor is included in the circuit to help stabilize the power supply voltage, smoothing out minor fluctuations and ensuring cleaner readings from the sensor. Once the Arduino's processor receives the analog voltage, a custom program written in the Arduino IDE processes the raw ADC counts, converts them into actual temperature units, and formats the data. This calculated temperature is then transmitted to a 16x2 LCD display, which visually renders the information for the user in real-time. The display circuit incorporates a 220-ohm resistor to properly limit the current flowing through the LCD backlight, preventing damage and maintaining optimal brightness. Additionally, a 1-kilo-ohm resistor is utilized within the system setup, often serving as a pull-up or current-limiting element for interface stability. Jumper wires and a 2-pin connector form the physical electrical pathways, securely bridging the Arduino Uno, the sensors, passive components, and the display together into a cohesive, functional monitoring device.