Arduino Wakes My PC

Arduino Wakes My PC

This Arduino progject using arduino Uno + ethernet shield(W5100). It’s Application. used W5100 chip WOL(Wake on lan).

I needed a way to bring it on whenever I wanted. So I tought I could use an Arduino with an Ethernet shield to send the Wake On Lan packets.

The UdpRaw allowed me to send raw packets, so all I needed was to implement the “magic packet” – it consists of 6 times 0xFF followed by 16 times the target MAC address.

So, first, I store that MAC address in a byte array. Take “00:00:00:36:45:C1″ as my example target MAC:

byte wolMac[] = { 0x00,0x00,0x00,0x36,0x45,0xC1 };

Now, all I need is to copy that 16 times, after 6 * 0xFF (102 bytes total). This is how I did it:

byte all[102];
int i,c1,j=0;

for(i = 0; i < 6; i++,j++){
  all[j] = 0xFF;
}
for(i = 0; i < 16; i++){
  for( c1 = 0; c1 < 6; c1++,j++)
    all[j] = wolMac[c1];
}

After running this code, the “all” array will have the complete magic packet, ready to send:

UdpRaw.sendPacket(all,102,targetIp,targetPort);

So to test it, I thought of a simple program that sends the packet when a pushbutton is pressed. To do this, I used an interrupt at pin 2. Basically, the Arduino keeps listening to that pin and whenever it raises from LOW to HIGH, it will execute a certain function.

After this, I plan to make the Arduino to listen to a port from the Internet and whenever it receives a certain packet sequence, it wakes the computer. This way I’ll be able to power up the computer from anywhere in the world!

Here is the whole Arduino code:

/*
* Arduino WakeMyPc
 * Ricardo Dias
 * http://ricardo-dias.com/
 *
 * This sketch sends the "magic packet" to wake up
 * a PC on Local Area Network when a push-button
 * is pressed.
 */

#include <Ethernet.h>
#include <UdpRaw.h>

// ARDUINO CONFIG
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // Arduino MAC
byte ip[] = { 192, 168, 1, 112 }; // Arduino IP
byte gw[] = { 192, 168, 1, 254 }; // Gateway IP address
int localPort = 8888; //local port to listen on

// THE TARGET
byte targetIp[] = { 192, 168, 1, 255 };
int targetPort = 5456;
byte wolMac[] = { 0x00,0x00,0x00,0x36,0x45,0xC1 }; // The target PC Mac Address

void setup() {
  Ethernet.begin(mac,ip,gw);
  UdpRaw.begin(localPort);

  // Will run the sendPkt() function when a button wired to
  // pin 2 is pressed
  attachInterrupt(0, sendPkt, RISING);
}

void loop() {
  delay(1);
}

void sendPkt(){
  // The 'magic packet' consists of 6 times 0xFF followed by 16 times
  // the hardware address (MAC).

  byte all[102];
  int i,c1,j=0;

  for(i = 0; i < 6; i++,j++){
    all[j] = 0xFF;
  }
  for(i = 0; i < 16; i++){
    for( c1 = 0; c1 < 6; c1++,j++)
      all[j] = wolMac[c1];
  }

  UdpRaw.sendPacket(all,102,targetIp,targetPort);
}

original link – http://ricardo-dias.com/2010/11/20/arduino-wakes-my-pc/