Auto Cooling Fan Using Servo and DHT11 Temperature and Humidity Sensor With Arduino

In this tutorial we will learn how to start & rotate a fan when the temperature raises above a certain level.

Step 1: What You Will Need

• DHT11 sensor
• Arduino UNO (or any other board)
• Fan module L9110
• OLED Display
• Servo motor
• Jumper wires
• Breadboard
• Visuino program: Download Visuino

Step 2: The Circuit

 

 

• Connect Servo motor “Orange” (signal) pin to Arduino Digital pin[2]
• Connect Servo motor “Red” pin to Arduino positive pin[5V]
• Connect Servo motor “Brown” pin to Arduino negative pin[GND]
• Connect fan module pin [VCC] to arduino pin [5V]
• Connect fan module pin [GND] to arduino pin [GND]
• Connect fan module pin [INA] to arduino digital pin [5]
• Connect OLED Display pin[VCC] to Arduino pin[5V]
• Connect OLED Display pin[GND] to Arduino pin[GND]
• Connect OLED Display pin[SDA] to Arduino pin[SDA]
• Connect OLED Display pin[SCL] to Arduino pin[SCL]
• Connect DHT11 positive pin + (VCC) to Arduino pin +5V
• Connect DHT11 negative pin – (GND) to Arduino pin GND
• Connect DHT11 pin (Out) to Arduino digital pin (4)

Step 3: Start Visuino, and Select the Arduino UNO Board Type

The Visuino: https://www.visuino.eu also needs to be installed. Download Free version or register for a Free Trial.

Start Visuino as shown in the first picture Click on the “Tools” button on the Arduino component (Picture 1) in Visuino When the dialog appears, select “Arduino UNO” as shown on Picture 2

Step 4: In Visuino Add Components

 

 

Add “OLED” display component

• Add “Sine Analog Generator” component
• Add “Servo” component
• Add “DHT” component
• Add “Analog Value” component
• Add 2X “Compare Analog Value” component
• Add “OLED” component

Step 5: In Visuino Set Components

  

• Select “SineAnalogGenerator1” and in the properties window set Amplitude to 0.30 and Frequency to 0.1,set enabled to False and click on the Pin icon and select Boolean sink pin
• Select “CompareValue1” and in the properties window set Value to 24 (temperature that will start the fan) and Compare Type to ctBiggerOrEqual
• Select “CompareValue2” and in the properties window set Value to 24 (temperature level that will stop the fan) and Compare Type to ctSmaller
• Double click on the “AnalogValue1” and in the Elements window drag “Set Value” to the left
• In the properties window set Value to 0.5
• In the Elements window drag another “Set Value” to the left
• In the properties window set Value to 1

Double click on the “DisplayOLED1”

In the Elements window:

• Drag “Draw Text” to the left and in the properties window set Text to “TEMP”
• Drag “Text Field” to the left and in the properties window set Size to 2 and Y to 9
• Drag “Draw Text” to the left and in the properties window set Text to “HUMIDITY” and Y to 26
• Drag “Text Field” to the left and in the properties window set Size to 2 and Y to 36
• Drag “Draw Text” to the left and in the properties window set Text to “FAN ACTIVE” and Y to 54 and set Enabled to false, click on the pin icon and set BooleanSinkPin

Close the Elements window

Step 6: In Visuino Connect Components

• Connect SineAnalogGenerator1 pin [Out] to Servo1 pin [In]
• Connect Servo1 pin [Out] to Arduino digital pin [2]
• Connect “HumidityThermometer1” pin[Sensor] to Arduino digital pin [4]
• Connect “HumidityThermometer1” pin[Temperature] to DisplayOLED1>TextField1 pin[In] and CompareValue1 pin[In] and CompareValue2 pin[In]
• Connect “HumidityThermometer1” pin[Temperature] to DisplayOLED1>TextField2 pin[In]
• Connect “CompareValue1” pin[Out] to DisplayOLED1>DrawText3 pin[Iclock] and pin[Enabled]
• Connect “CompareValue1” pin[Out] to AnalogValue1>Set Value1 pin[In] and SineAnalogGenerator1 pin[Enabled]
• Connect “CompareValue2” pin[Out] to AnalogValue1>Set Value2 pin[In]
• Connect “DisplayOLED1” pin I2C [Out] to Arduino board I2C [In]

 

Step 7: Generate, Compile, and Upload the Arduino Code

In Visuino, at the bottom click on the “Build” Tab, make sure the correct port is selected, then click on the “Compile/Build and Upload” button.

Step 8: Play