How to remotely turn on a Raspberry Pi? As this topic comes up over and over again, find here a prototype of a solution.
Assume you have a device which should not be powered up all the time - like Rasperry Pi :) You want to be able to power up your device via standard wake on lan (WOL). This sketch can help with this.
To enable "wake on lan" for your device, you need to power your device with a "smart" power outlet. Preferably you use some Tasmota enabled device, like a reflashed Sonoff Pow, or e.g. a Shelly-1. By using this smart power outlet you can enable / disable the power for your device.
Function of this sketch is simple: It is waiting for a WOL package for your device. YOu just need to grab a "virtual" Mac-Address, where you will send your WOL requests to. The sketch will capture them and once retrieved, connect to the smart power outlet and turn the power on.
This sketch is heavilly based on this this post: https://www.hackster.io/erkr/wake-on-lan-wol-gateway-a6a639
It seems that Wake on Lan is not always Wake on Lan! This sketch works only with magic packages which are sent to UDP port 12287 - this seems to be some sort of "standard" in the windows world. But this sketch will e.g. not work with "etherwake"!
As mentioned above, the sketch is only suitible to wake a device with WOL sent via broadcast, based on TCP/IP. If you e.g. want to use a FRITZ!Box to start your Pi, this will not work, as the FRITZ!Box actually sends a WOL package with a different ethernet protocol. To deal with this situation, you can use a small python script:
import socket, sys
import requests
from struct import *
#Convert a string of 6 characters of ethernet address into a dash separated hex string
def eth_addr (a) :
b = "%.2x:%.2x:%.2x:%.2x:%.2x:%.2x" % (a[0] , a[1] , a[2], a[3], a[4], a[5])
return b
#create a AF_PACKET type raw socket (thats basically packet level)
#define ETH_P_ALL 0x0003 /* Every packet (be careful!!!) */
try:
s = socket.socket( socket.AF_PACKET , socket.SOCK_RAW , socket.ntohs(0x0003))
except socket.error as msg:
print ('Socket could not be created. Error Code : ' + str(msg[0]) + ' Message ' + msg[1])
sys.exit()
# receive a packet
while True:
packet = s.recvfrom(65565)
#packet string from tuple
packet = packet[0]
#parse ethernet header
eth_length = 14
eth_header = packet[:eth_length]
eth = unpack('!6s6sH' , eth_header)
eth_protocol = socket.ntohs(eth[2])
#if ( eth_protocol == 16904):
# print ('Destination MAC : ' + eth_addr(packet[0:6]) + ' Source MAC : ' + eth_addr(packet[6:12]) + ' Protocol : ' + str(eth_protocol))
# for i in range(40):
# v = "%.2x " % (packet[i])
# print ( v, end='' )
# print ()
#Parse IP packets, IP Protocol number = 8
if eth_protocol == 16904:
#Parse IP header
#take first 20 characters for the ip header
mac_destination = packet[0:6]
mac_source = packet[6:12]
protocol = packet[12:14]
sync_stream = packet[14:20]
mac_wol = packet[20:26]
print ('Destination MAC : ' + eth_addr(mac_destination) + ' Source MAC : ' + eth_addr(mac_source) + ' Protocol : ' + str(protocol) + ' Target MAC : ' + eth_addr(mac_wol))
if (mac_wol[0] == 0xE4) and (mac_wol[1] == 0x5F) and (mac_wol[2] == 0x01) and (mac_wol[3] == 0x54) and (mac_wol[4] == 0x1D) and (mac_wol[5] == 0xE1):
print ( "WOL Signal detected ...")
response = requests.get("http://192.168.20.100/cm?cmnd=Power%20on")```This script is basically sniffing for all packets - regardless if TCP/IP, UDP, ... but it is waiting for packages with protocol "16904" (WOL). If such a package comes in, it compares the destination MAC. If the MAC is as expected, a web request to power the smart plug is issued ... This approach also would work with eatherwake! So far however I did not find a reasonable way to implement this on a ESP8266.