arduinotemp.docx

8/10/2019 ArduinoTemp.docx

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ESE Labs, SEAS, Univ of Pennsylvania, [email protected] Page 1 of 4

UNIVERSITY OF PENNSYLVANIADEPARTMENT OF ELECTRICAL AND SYSTEMS ENGINEERINGESE UNDERGRADUATE LABORATORYSelf Paced Arduino Laboratory

Temperature sensor using the Arduino board

Goal:To measure and display temperature using an Arduino Board interfaced with 16x2 LCD

Display.

Parts Required

1. Arduino board2. USB Cable

3. LM 34, temperature sensor

4. Wires

Procedure:a. Temperature Sensor

LM34 is a 3-pin device with 5V and GND inputs and temperature output. The LM34 is designed

to output 10 mV per degree Fahrenheit, so a reading of 0.73 V on the output pin means thetemperature is 73F. In order to use this on your Arduino you will have to connect the 5V and

GND pins to the corresponding buses on your Arduino, and wire the output pin to an analog

input pin.

Figure 1: Temperature Sensor Figure 2: Arduino Board


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b. Display temperature

In order to display the measured temperature values you will have to wire the 16x2 LCD display

(Figure 4) to 6 Digital Output pins of the Arduino board.

Wire the pins according to the following assignments:

LCD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Arduino

BoardGND +5V GND 12 GND 11 - - - - 5 4 3 2 +5V GND

Figure 4: 16X2 Liquid Crystal Display

LCD Display library functions are used interface the Digital I/O pins of the Arduino board withthe LCD Display. lcd.print(xxxxx) function is used to display the measured values. Refer tothe above code.

c. Compile and download the working code to the Arduino Board

Compile the following code in Arduino IDE and download it to the Arduino Board.

/*

TempSensor - University of Pennsylvania

Uses the LiquidCrystal Library to display

the real time temperature in deg. F using

the LM34 IC

The circuit:

* LCD RS pin to digital pin 12


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* LCD Enable pin to digital pin 11

* LCD D4 pin to digital pin 7




*/

// include the library code:

#include

// initialize the library with the numbers of the interface pins

LiquidCrystal lcd(12, 11, 5,4,3,2);

float tempVal;

float sensorVal;

int sensorPin = 4;

void setup() {

// set up the LCD's number of rows and columns:

lcd.begin(16, 2);

// Print a message to the LCD.

lcd.print("Temp (deg. F)");

// initialize serial communication:

Serial.begin(9600);

}

void loop() {

lcd.clear();

// get temperature

sensorVal = (analogRead(sensorPin)/1023.0)*5.0;

tempVal = sensorVal*100.0;


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delay(100);

// set the cursor to column 0, line 1

// (note: line 1 is the second row, since counting begins with 0):

lcd.print("Temp (deg. F):");

lcd.setCursor(0, 1);

lcd.print(tempVal);

delay(1000); //0.5sec

}

d. Questions:

i. Explain how is temperature data acquired from the sensor using the Arduino board?

ii. What are the maximum and minimum values of temperature you can measure using

the Arduino board?iii. Can you display the temperature in

oC and K?

Figure 5: Measurement of temperature using Arduino board

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