Temperature sensor error

Projects Programming
1

I'm on an Arduino UNO, and my temp sensor is DHT11. I ran this code:

const int sensorPin = A5;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int sensorVal = analogRead(sensorPin);
  Serial.print("Sensor Value: ");
  Serial.print(sensorVal);

  float voltage = (sensorVal/1024.0) * 5.0;
  Serial.print(", Volts: ");
  Serial.print(voltage);

  float temperature = (voltage - .5) * 100;
  Serial.print(", degrees C: ");
  Serial.println(temperature);

  delay(1000);
}

But my output wasn't something normal like 20C, it was Sensor Value: 1023, Volts: 5.00, degrees C: 449.51, I tried changing the jumper wires, changing its position on the breadboard. I tried running some other code that was from the Arduino Projects Book, and I still got wrong numbers. Does anyone know how to fix that?

2

Have your read the DHT11 Datasheet?

3

The DHT11 is not an analog sensor that you can read on an analog port. It communicates with a digital protocol:


The best to read its data is to use libraries such as DHT or write your own reading function, as here

4 
Sensor Value: 1023

Looks like a wiring problem as analogRead() returns 1023 when the input voltage equals the reference voltage (here 5V)

Shouldn't you be using the DHT11 library to read from the sensor ?
How is the sensor wired ?

5

Does anyone know how to fix that?

A search for "Arduino DHT11 tutorial" gets 270000 results so, yeah, somebody does.

6

Ouch, that hurt :stuck_out_tongue:

Well, thanks for the replies and guides