Temperature Sensing Basics with LM35
Learn how to measure temperature using the LM35 analog sensor with your Arduino Uno. This sensor converts temperature directly into voltage!
What is the LM35 Temperature Sensor?
The LM35 is a precision integrated-circuit temperature sensor that outputs a voltage directly proportional to the Celsius temperature. It's one of the easiest temperature sensors to use!
Key Specifications:
- Output Scale 10mV per °C
- Temperature Range 0°C to 100°C
- Accuracy ±0.5°C typical
- Operating Voltage 4V to 30V
Simple Math:
• At 0°C → Output = 0V
• At 25°C → Output = 250mV (0.25V)
• At 100°C → Output = 1000mV (1V)
• At 0°C → Output = 0V
• At 25°C → Output = 250mV (0.25V)
• At 100°C → Output = 1000mV (1V)
LM35 Pin Configuration
The LM35 has only 3 pins. When looking at the flat face with text:
| Pin | Name | Connect To |
|---|---|---|
| 1 | Vs (Power) | Arduino 5V |
| 2 | Vout (Signal) | Arduino A0 |
| 3 | GND (Ground) | Arduino GND |
Interactive Circuit Diagram
This circuit shows the LM35 temperature sensor connected to Arduino Uno with an LED indicator that lights up when temperature exceeds a threshold.
Interactive visualization — available in the full lesson