anonymous

Published February 10, 2015

Remote switch with LinkitONE

Turning off my ADSL antenna automatically when I don't need it.

IntermediateFull instructions provided765

Things used in this project

Hardware components

2 2n3904 NPN transistor

Bistable (latching) relay

Breadboard (generic)

BreadBoard wires

2 resistor 120

2 resistor 1K

Story

Remote Switch

The need: I have a wireless ADSL connection, with an antenna placed on my roof. This antenna is always turned on, even when my home network is off. So I decided to build a proof of concept device to turn on or off this antenna with a relay, by looking for the presence of my SSID on the air. In this way, when I turn off my wireless router, the antenna is switched of as well.

On the other side, when I switch on my router, the antenna is turned on again, letting me on internet again.

The concept is quite easy: when the module see my SSID on the air, it turns on a bistable relay, when it does not see any more, it turns the relay off.

I choose to use a bistable relay because it does not need current to hold the position set. So if the power go away, the position is maintained (and also it consume less current).

How I did it

The realization is quite simple. Two PINs of the Linkit ONE control the status of the relay. Since the Linkit ONE does not provide enough current to the PIN to drive a relay (as it is stated in the documentation), I used a couple of transistor to create the circuit needed:

The connection to the latching relay is quite simple. It has 4 PINs:

positive
negative
set
reset

Set and Reset can receive a signal from the LinkitONE. When using voltages over 3v never hold SET or RESET for longer than 1/2 second, shorter if possible.

Schematics

File missing, please reupload.

Code

Code

#include 
#include 

#define DELAY      60000
#define PIN_ON     3
#define PIN_OFF    9

char ssid[] = "YOURSSID";
char pass[] = "YOURPWD";

int relayStatus = -1;

void setup()
{
  Serial.begin(9600);
  LWiFi.begin();

  // Iniztialize PIN for relay
  pinMode(PIN_ON,OUTPUT);
  pinMode(PIN_OFF,OUTPUT);
  digitalWrite(PIN_ON,LOW);
  digitalWrite(PIN_OFF,LOW);

  delay(1000);
}

void loop() 
{
  Serial.println();
  Serial.print("Searching for AP...");
  if ( LWiFi.connectWPA(ssid, pass) != 1 )
  {
    Serial.println("Not Found");

    // The SSID is not present, turn off the relay
    if ( relayStatus == -1 || relayStatus == 1 )
    {
      relayStatus = 0;
      switchRelay(0);
    }
  }
  else
  {
    Serial.println("Found!");

    // The SSID has been found, turn on the relay
    if ( relayStatus == -1 || relayStatus == 0 )
    {
      relayStatus = 1;
      switchRelay(1);
    }
  }

  LWiFi.disconnect();

  // Sleeps for a while...
  delay(DELAY);
}

//
void switchRelay(int command)
{
  // Send the HIGH signal to the corret PIN
  if ( command == 1 )
  {
    Serial.println("Turning ON relay");
    digitalWrite(PIN_ON,HIGH);
    delay(50);
    digitalWrite(PIN_ON,LOW);
  } 
  else
  {
    Serial.println("Turning OFF relay");
    digitalWrite(PIN_OFF,HIGH);
    delay(50);
    digitalWrite(PIN_OFF,LOW);
  } 
}

Credits

anonymous

Comments

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Remote switch with LinkitONE

Remote switch with LinkitONE

Things used in this project

Hardware components

Story

Remote Switch

How I did it

Schematics

Fritzing

Code

Code

Credits

Comments

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