Temperature Meter using LM35 Analog Sensor and Arduino Nano LCD Shield

Another project which display the ambient temperature on 16X2 LCD, Project is based on compact multipurpose Arduino Nano LCD shield and LM35 analog temperature sensor, shield also provided with 3 Tactile Switches, Relay, Power MOSFET, Trimmer Potentio-meter to create multi projects. Circuit works with 5V DC, can be power up from USB or separate header connector.  

Download PDF Document

Download Arduino Code for LCD Based Temperature Meter

Arduino Pins LCD

  • LCD RS pin to digital pin 12
  • LCD Enable pin to digital pin 11
  • LCD D4 pin to digital pin 5
  • LCD D5 pin to digital pin 4
  • LCD D6 pin to digital pin 3
  • LCD D7 pin to digital pin 2
  • LCD R/W pin to ground

Arduino Pins Various Devices

  • Switch 1 Arduino Pin A3
  • Switch 2 Arduino Pin D6
  • Switch 3 Arduino Pin D7
  • Current Sensor ACS714 Arduino Pin A5
  • Trimmer Potentio-Meter Arduino Pin A0
  • LM35 Sensor Arduino Pin A4
  • Power MOSFET Arduino Pin D9
  • Relay Arduino Pin D8

The LM35 series are precision integrated-circuit temperature devices with an output voltage linearly-proportional to the Centigrade temperature. The LM35 device has an advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to subtract a large constant voltage from the output to obtain convenient Centigrade scaling. The LM35 device does not require any external calibration or trimming to provide typical accuracies of ±¼°C at room temperature and ±¾°C over a full −55°C to 150°C temperature range. Lower cost is assured by trimming and calibration at the wafer level. The low-output impedance, linear output, and precise inherent calibration of the LM35 device makes interfacing to readout or control circuitry especially easy. The device is used with single power supplies, or with plus and minus supplies. As the LM35 device draws only 60 µA from the supply, it has very low self-heating of less than 0.1°C in still air. The LM35 device is rated to operate over a −55°C to 150°C temperature range, while the LM35C device is rated for a −40°C to 110°C range (−10° with improved accuracy). The LM35-series devices are available packaged in hermetic TO transistor packages, while the LM35C, LM35CA, and LM35D devices are available in the plastic TO-92 transistor package.

LM35 Features
Calibrated Directly in Celsius (Centigrade)
Linear + 10-mV/°C Scale Factor
0.5°C Ensured Accuracy (at 25°C)
Rated for Full −55°C to 150°C Range
Suitable for Remote Applications
Low-Cost Due to Wafer-Level Trimming
Operates From 4 V to 30 V
Less Than 60-µA Current Drain
Low Self-Heating, 0.08°C in Still Air
Non-Linearity Only ±¼°C Typical
Low-Impedance Output, 0.1 Ω for 1-mA Load

Arduino Code


#include<LiquidCrystal.h>

LiquidCrystal lcd(12,11,5,4,3,2);
const int inPin = A4;
void setup()
{
lcd.begin(16,2);
}
void loop()
{
int value = analogRead(inPin);
lcd.setCursor(0,1);
float millivolts = (value / 1023.0) * 5000;
float celsius = millivolts / 10;
lcd.clear();
lcd.setCursor(0,0);
lcd.print(celsius);
lcd.print(“C”);
lcd.setCursor(0,1);
lcd.print((celsius * 9)/5 + 32);
lcd.print(“F”);
delay(1000);
}

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