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Project Notes

#595 LM35 Temperature Sensor

Reading ambient temperature with the LM35 and an Arduino without output display on a Nokia 5110 LCD.



This circuit uses an LM35 Precision Centigrade Temperature Sensor to measure ambient temperature, and display the result on a Nokia 5110 comptible LCD.

The LM35 is part of a series of easy to use temperature sensors:

Sensor Output Voltage Linearity
LM34 proportional to temperature in Fahrenheit (ºF) 10mV/ºF
LM35 proportional to temperature in Celsius (ºC) 10mV/ºC
LM335 proportional to temperature in Kelvin (ºK) 10mV/ºK

Specifications for the LM35:

  • Directly calibrated in ̊Celsius (Centigrade)
  • 0.5̊C accuracy
  • Less than 60 μA current drain
  • Low impedance output, 0.1 Ω for 1 mA load
  • Rated for full −55̊ to +150 ̊C range





See LM35.ino for the sketch.

Reading temperature is straight-forward:

  • LM35 output voltage is read with analog input
  • scaled to 10mV/ºC

Libraries used:

  • u8glib library used for driving the LCD

Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.