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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

About LEAP#595 SensorsLM35LCDArduino
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LEAP is my personal collection of electronics projects, 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 (IMHO!).

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