Crowtail- Relay

 The Relay is the most common used module in actually application such as home automation, and sometimes you need to control large current such as the air conditioning/water heater. That is what this Large Current Relay Module can be help.

Features

• High Switching Current

Specification

Usage

Intelligent Temperature Control Fan

1.Hardware Connection

2.Copy the demo code to your sketch, then upload to Arduino or Crowduino board.You can set a threshold temperature value to control the realy ON or OFF, then control the fan work or not.

/*
Temperature sensor connect to AO
Relay connetct to D5
*/

#include <math.h>
int a;
float temperature;
int B=3975;                  //B value of the thermistor
float resistance;
// Connect the Relay to digital pin D5.
// give it a name:
int Relay = 5;

void setup()
{
 // initialize the digital pin as an output.
 pinMode(Relay, OUTPUT);  
 Serial.begin(9600);  
}

void loop()
{
   a=analogRead(0);
   resistance=(float)(1023-a)*10000/a; //get the resistance of the sensor;
   temperature=1/(log(resistance/10000)/B+1/298.15)-273.15;//convert to temperature via datasheet ;
   delay(1000);
   Serial.print("Current temperature is ");
   Serial.println(temperature);
   if(temperature>20)
   {
         digitalWrite(Relay, HIGH);  //if temperature >20 degree,turn the Relay on,fan working
   }
   else
   {
        digitalWrite(Relay, LOW);//if temperature <=20 degree,turn the Relay off,fan not working
   }
}

3.When the temperature above 20 degrees,the fan will working.

Resource

• Relay Program
• DSM501 Dust Sensor Datasheet