Arduino

Arduino temperature and humidity control with Wi-Fi

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By Jackson Taylor

When it comes to monitoring environmental conditions, particularly temperature and humidity, an efficient system is essential. With the power of Arduino and Wi-Fi connectivity, you can easily create a smart temperature and humidity control system that allows for remote monitoring and management. In this guide, we will walk you through the process of building your very own Arduino-based system with Wi-Fi capabilities for real-time control and monitoring.

What is Arduino Temperature and Humidity Control?

Arduino temperature and humidity control refers to the use of an Arduino microcontroller to monitor and adjust environmental parameters, specifically temperature and humidity. By integrating sensors and Wi-Fi modules, you can create an automated system that can send data to a mobile device or computer, allowing you to control and view conditions remotely.

Components Required for the Project

Before diving into the setup process, it’s important to gather the necessary components. Below is a list of essential items for building your own Arduino temperature and humidity control system with Wi-Fi:

1. Arduino Board (e.g., Arduino Uno or Nano)

The Arduino board serves as the central processing unit for the system. It reads data from the sensors and controls connected devices.

2. DHT11 or DHT22 Temperature and Humidity Sensor

The DHT11 and DHT22 are commonly used sensors for measuring temperature and humidity. While the DHT11 is more affordable, the DHT22 offers greater accuracy and a wider range of measurement.

3. ESP8266 Wi-Fi Module

The ESP8266 is a low-cost Wi-Fi module that allows the Arduino to connect to a network, enabling remote monitoring via a web server or mobile app.

4. Jumper Wires

These wires will connect the components, including the Arduino, sensor, and Wi-Fi module.

5. Breadboard

A breadboard is helpful for prototyping the circuit before soldering.

6. Power Supply

A 5V power supply is required to power the Arduino and the Wi-Fi module.

Wiring and Connecting the Components

Now that you have all the necessary components, let’s move on to the wiring process. This is a crucial step to ensure your Arduino-based temperature and humidity control system works properly.

Step-by-Step Wiring

  1. Connect the DHT Sensor to Arduino:
    • Connect the VCC pin of the DHT sensor to the 5V pin on the Arduino.
    • Connect the GND pin of the sensor to the GND pin on the Arduino.
    • Connect the DATA pin of the DHT sensor to a digital input pin on the Arduino (for example, pin 2).
  2. Integrating the ESP8266 Wi-Fi Module:
    • Connect the VCC pin of the ESP8266 to the 3.3V pin of the Arduino.
    • Connect the GND pin of the ESP8266 to the GND pin of the Arduino.
    • Connect the TX pin of the ESP8266 to the RX pin of the Arduino (pin 0).
    • Connect the RX pin of the ESP8266 to the TX pin of the Arduino (pin 1).
Tip: Ensure you have sufficient power for the ESP8266 module, as it can draw more current than the Arduino’s 3.3V output can supply. It’s recommended to use an external power supply for the ESP8266 if necessary.

Writing the Code

With the hardware connected, the next step is to write the code that will enable the Arduino to read data from the sensor and send it over Wi-Fi. Below is an example of code that integrates both the DHT22 sensor and the ESP8266 Wi-Fi module.
cpp
#include <DHT.h> #include <ESP8266WiFi.h> #define DHTPIN 2 // DHT sensor connected to pin 2 #define DHTTYPE DHT22 // DHT 22 (AM2302) DHT dht(DHTPIN, DHTTYPE); const char* ssid = “your_SSID”; // Wi-Fi SSID const char* password = “your_PASS”; // Wi-Fi Password void setup() { Serial.begin(115200); dht.begin(); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(1000); Serial.println(“Connecting to WiFi…”); } Serial.println(“Connected to WiFi”); } void loop() { delay(2000); // Wait for 2 seconds before reading the sensor float h = dht.readHumidity(); float t = dht.readTemperature(); if (isnan(h) || isnan(t)) { Serial.println(“Failed to read from DHT sensor”); return; } Serial.print(“Humidity: “); Serial.print(h); Serial.print(” %\t”); Serial.print(“Temperature: “); Serial.print(t); Serial.println(” *C”); // Additional code to send data over Wi-Fi can be added here. }

What Does the Code Do?

  • DHT Sensor Setup: The code initializes the DHT22 sensor to read temperature and humidity data.
  • Wi-Fi Connection: It connects to your Wi-Fi network using the ESP8266 Wi-Fi module.
  • Data Reading: Every 2 seconds, the temperature and humidity are read from the sensor and displayed in the serial monitor.

Sending Data to the Cloud

Once the Arduino reads the data, you may want to send it to the cloud or a web server for remote access. This step is where the ESP8266 Wi-Fi module comes in.

Option 1: Using Blynk for Mobile Access

One easy way to monitor the data is by using the Blynk app, which allows you to create a custom interface to display your temperature and humidity readings on your mobile device.
  1. Install the Blynk App: Download the Blynk app from the App Store or Google Play Store.
  2. Create a New Project: In the Blynk app, create a new project, select your board (Arduino Uno), and Wi-Fi as the connection type.
  3. Generate an Authentication Token: This token will be used in the code to connect the Arduino to the Blynk server.

Option 2: Use ThingSpeak for Cloud Monitoring

If you prefer cloud-based monitoring, ThingSpeak is a great option. With ThingSpeak, you can send data from your Arduino to the cloud and access it from anywhere.
  1. Create a ThingSpeak Account: Sign up at ThingSpeak.
  2. Generate an API Key: This key will be used to send data to ThingSpeak.
  3. Modify Your Code: Update your code to include the ThingSpeak API key and send data to the channel.
cpp
#include <ThingSpeak.h> #include <WiFi.h> char ssid[] = "your_SSID"; char pass[] = "your_PASS"; WiFiClient client; unsigned long myChannelNumber = YOUR_CHANNEL_ID; const char * myWriteAPIKey = "YOUR_API_KEY"; void setup() { WiFi.begin(ssid, pass); ThingSpeak.begin(client); } void loop() { float h = dht.readHumidity(); float t = dht.readTemperature(); if (!isnan(h) && !isnan(t)) { ThingSpeak.setField(1, h); ThingSpeak.setField(2, t); ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey); } delay(2000); }

Real-Time Monitoring

With the data sent to the cloud, you can view your temperature and humidity levels in real-time via a dashboard. Both Blynk and ThingSpeak offer intuitive user interfaces that allow for easy data visualization.

Benefits of Arduino Temperature and Humidity Control with Wi-Fi

Building a Wi-Fi-enabled temperature and humidity control system using Arduino offers numerous benefits, including:
  1. Remote Monitoring: With Wi-Fi connectivity, you can monitor temperature and humidity from anywhere using your smartphone or computer.
  2. Automation: Set thresholds for temperature and humidity, and automate actions like turning on a fan or heater when conditions exceed a certain level.
  3. Data Logging: By sending data to the cloud, you can keep track of environmental changes over time.
  4. Cost-Effective: Arduino and Wi-Fi modules are affordable, making this project budget-friendly.

Conclusion

Creating an Arduino-based temperature and humidity control system with Wi-Fi is a rewarding project that combines hardware and software to provide remote monitoring and control. By using simple components like the DHT22 sensor and ESP8266 Wi-Fi module, you can easily set up your system and monitor environmental conditions in real-time. Whether you’re looking to manage your greenhouse, server room, or just ensure a comfortable living environment, this project provides an excellent introduction to the world of IoT and smart systems.
See also
Arduino voice control with text-to-speech

Arduino security system with cameras

Arduino self-driving car with remote control