Temperature sensor always reads high temps

Using Arduino Sensors
#1

So I have followed this diagram: How to wire LM35 to Arduino Uno

And I used the following code:

//Variables
float tempC;
int tempPin = 1; //Temp sensor is plugged into An0


void setup() {
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  tempC = analogRead(tempPin);          // read the analog value from the lm35 sensor.
  tempC = (5.0 * tempC * 100.0)/1024.0; // convert the analog input to temperature in centigrade.
  Serial.println((byte)tempC);
  delay(3000); //3 second delay
}

And I get temps that are 215 degrees celcius or higher. It works for a lot of people and it doesn't for me. What could be wrong? Could I have a defect temperature sensor?

#2

I tested your codes unchanged on UNO; the LM35 is responding well!

Please check wiring, continuity of the jumpers, and the correct orientation of the sensor.

#3

GolamMostafa:
Please check wiring, continuity of the jumpers, and the correct orientation of the sensor.

My orientation is correct. I can’t check continuity since I don’t have a meter for that.

#4

uRThow:
My orientation is correct. I can't check continuity since I don't have a meter for that.

Without a meter, you can check the continuity of your jumper wires this way:

#5 
int tempPin = 1; //Temp sensor is plugged into An0

In the circuit you connect to A3, in the comment you say it's A0 and in the code you use A1 (given you're actually using an Arduino UNO). What's true now?

#6

pylon:

int tempPin = 1; //Temp sensor is plugged into An0

In the circuit you connect to A3, in the comment you say it's A0 and in the code you use A1 (given you're actually using an Arduino UNO). What's true now?

I plugged it into analog pin 1 but never updated the comment in the code.

#7

Try with another LM35; if you don't have a second LM35, insert 3.3V from UNO into A1; you should get a reading of about 67 degC.

#8

GolamMostafa:
Without a meter, you can check the continuity of your jumper wires this way:

I checked my wires and the continuity are okay on all of them. What could be the problem?

#9

GolamMostafa:
Try with another LM35; if you don’t have a second LM35, insert 3.3V from UNO into A1; you should get a reading of about 67 degC.

If I use my equation I get about 69 degC.

#10

Okay so it works now! It says about 27 degrees C which is true, but sometimes it shoots up to about 255 or down to 0! Any clue why?

#11