DHT12 temperature sensor and Chipkit Max32 example

This article shows how to connect a DHT12 to a Chipkit Max32

The DHt12 is an upgraded version of the classic DHT11 humidity temperature sensor, it is fully downward compatible, more precise and adds an I2C interface.

Features:

compact size
low power consumption
low voltage operation
Standard I2C and 1-wire interface.

Sensing range
Temperature: -20 ~ +60 C
Humidity: 20-95 RH
Humidity:
Resolution: 0.1%RH
Repeat: -+ 1%RH
Precision 25C @ -+5RH
Temperature:
Resolution: 0.1C
Repeat: -+0.2C
Precision: 25C @ -+0.5C
Power: DC 2.7-5.5V
Normal current 1mA
Standby current 60uA
Sample cycle: > 2 seconds

Pin interface: 1. VDD 2. SDA 3. GND 4. SCL (connect to GND when use as 1-wire)

Layout

This shows how to connect the DHT12 to an Arduino Uno

chipkit and DHT12 connection

Code

This is from https://github.com/dplasa/dht

[codesyntax lang=”cpp”]

#include <Wire.h>
#include <dht.h>

dht12 DHT(0x5c);

void setup()
{
  Serial.begin(9600);
  Serial.println(F("DHT12 TEST PROGRAM"));
}

void loop()
{
  unsigned long b = micros();
  dht::ReadStatus chk = DHT.read();
  unsigned long e = micros();

  Serial.print(F("Read sensor: "));
  switch (chk)
  {
    case dht::OK:
      Serial.print(F("OK, took "));
      Serial.print (e - b); Serial.print(F(" usec, "));
      break;
    case dht::ERROR_CHECKSUM:
      Serial.println(F("Checksum error"));
      break;
    case dht::ERROR_TIMEOUT:
      Serial.println(F("Timeout error"));
      break;
    case dht::ERROR_CONNECT:
      Serial.println(F("Connect error"));
      break;
    case dht::ERROR_ACK_L:
      Serial.println(F("AckL error"));
      break;
    case dht::ERROR_ACK_H:
      Serial.println(F("AckH error"));
      break;
    default:
      Serial.println(F("Unknown error"));
      break;
  }

  Serial.print(F("Humidity: "));
  Serial.print((float)DHT.getHumidity()/(float)10);
  Serial.print(F("%, "));

  Serial.print(F(". Temperature (degrees C): "));
  Serial.print((float)DHT.getTemperature()/(float)10);

  Serial.print(F(", Dew Point (degrees C): "));
  Serial.println(DHT.dewPoint());

  delay(4000);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this

DHT12 TEST PROGRAM
Read sensor: OK, took 8555 usec, Humidity: 61.90%, . Temperature (degrees C): 23.60, Dew Point (degrees C): 15.86
Read sensor: OK, took 8000 usec, Humidity: 62.00%, . Temperature (degrees C): 23.60, Dew Point (degrees C): 15.88
Read sensor: OK, took 8000 usec, Humidity: 62.10%, . Temperature (degrees C): 23.60, Dew Point (degrees C): 15.91
Read sensor: OK, took 8000 usec, Humidity: 62.10%, . Temperature (degrees C): 23.60, Dew Point (degrees C): 15.91
Read sensor: OK, took 8000 usec, Humidity: 62.20%, . Temperature (degrees C): 23.50, Dew Point (degrees C): 15.84
Read sensor: OK, took 8000 usec, Humidity: 62.20%, . Temperature (degrees C): 23.50, Dew Point (degrees C): 15.84
Read sensor: OK, took 8000 usec, Humidity: 62.30%, . Temperature (degrees C): 23.60, Dew Point (degrees C): 15.96
Read sensor: OK, took 8000 usec, Humidity: 62.40%, . Temperature (degrees C): 23.60, Dew Point (degrees C): 15.99
Read sensor: OK, took 8000 usec, Humidity: 62.40%, . Temperature (degrees C): 23.50, Dew Point (degrees C): 15.89

Link

Under $1 for one of these sensors

1pcs DHT-12 DHT12 sensor Digital output Temperature and Humidity Sensor high quality