Circuit Documentation

Summary

This circuit is designed to collect temperature and humidity measurements using a DHT11 Humidity and Temperature Sensor interfaced with an Arduino UNO microcontroller. The sensor data is processed by the Arduino and output to the serial monitor. A resistor is included in the circuit to provide the necessary pull-up for the data line of the DHT11 sensor.

Component List

DHT11 Humidity and Temperature Sensor

• Description: A sensor that measures ambient temperature and humidity.
• Pins: VDD (Power Supply), DATA (Data Output), NULL (No Connection), GND (Ground).

Arduino UNO

• Description: A microcontroller board based on the ATmega328P.
• Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0-A5 (Analog Input), SCL, SDA, AREF, D0-D13 (Digital I/O).

Resistor

• Description: A passive two-terminal electrical component that implements electrical resistance as a circuit element.
• Value: 10,000 Ohms (10kΩ).

Wiring Details

DHT11 Humidity and Temperature Sensor

• VDD: Connected to the 5V output on the Arduino UNO.
• DATA: Connected to digital pin D2 on the Arduino UNO through a 10kΩ resistor.
• GND: Connected to the ground (GND) on the Arduino UNO.

Arduino UNO

• 5V: Provides power to the DHT11 sensor.
• D2: Receives the data signal from the DHT11 sensor through a 10kΩ resistor.
• GND: Common ground for the circuit.

Resistor (10kΩ)

• One end (pin1): Connected to the DATA pin of the DHT11 sensor.
• Other end (pin2): Connected to digital pin D2 on the Arduino UNO.

Documented Code

Arduino UNO Code for DHT11 Sensor

/**
 * This example demonstrates how to collect temperature and humidity measurements
 * from the Adafruit DHT11 sensor. Measurements are printed out to the serial monitor.
 *
 * - Make sure to first install the following libraries through the Arduino Library Manager:
 *   - DHT Sensor Library (by Adafruit)
 *   - Adafruit Unified Sensor (by Adafruit)
 * - When you open the serial monitor to view measurements from the DHT11, make sure
 * that you select 9600 baud so that the serial monitor can receive data from the Arduino.
 *
 * This example was originally written by Adafruit Industries LLC.
 */

#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>

#define DHTPIN 2     // Digital pin connected to the DHT sensor 

// Uncomment the type of sensor in use:
#define DHTTYPE    DHT11     // DHT 11

DHT_Unified dht(DHTPIN, DHTTYPE);

uint32_t delayMS;

void setup() {
  Serial.begin(9600);
  // Initialize device.
  dht.begin();
  Serial.println(F("DHTxx Unified Sensor Example"));
  // Print temperature sensor details.
  sensor_t sensor;
  dht.temperature().getSensor(&sensor);
  Serial.println(F("------------------------------------"));
  Serial.println(F("Temperature Sensor"));
  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("°C"));
  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("°C"));
  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("°C"));
  Serial.println(F("------------------------------------"));
  // Print humidity sensor details.
  dht.humidity().getSensor(&sensor);
  Serial.println(F("Humidity Sensor"));
  Serial.print  (F("Sensor Type: ")); Serial.println(sensor.name);
  Serial.print  (F("Driver Ver:  ")); Serial.println(sensor.version);
  Serial.print  (F("Unique ID:   ")); Serial.println(sensor.sensor_id);
  Serial.print  (F("Max Value:   ")); Serial.print(sensor.max_value); Serial.println(F("%"));
  Serial.print  (F("Min Value:   ")); Serial.print(sensor.min_value); Serial.println(F("%"));
  Serial.print  (F("Resolution:  ")); Serial.print(sensor.resolution); Serial.println(F("%"));
  Serial.println(F("------------------------------------"));
  // Set delay between sensor readings based on sensor details.
  delayMS = sensor.min_delay / 1000;
}

void loop() {
  // Delay between measurements.
  delay(delayMS);
  // Get temperature event and print its value.
  sensors_event_t event;
  dht.temperature().getEvent(&event);
  if (isnan(event.temperature)) {
    Serial.println(F("Error reading temperature!"));
  }
  else {
    Serial.print(F("Temperature: "));
    Serial.print(event.temperature);
    Serial.println(F("°C"));
  }
  // Get humidity event and print its value.
  dht.humidity().getEvent(&event);
  if (isnan(event.relative_humidity)) {
    Serial.println(F("Error reading humidity!"));
  }
  else {
    Serial.print(F("Humidity: "));
    Serial.print(event.relative_humidity);
    Serial.println(F("%"));
  }
}

Additional Arduino UNO (Unused in this circuit)

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

This additional Arduino UNO does not have any specific code associated with the current circuit configuration and is not used in the temperature and humidity measurement application.