Simple COntroller for Raspberry PI ON (scoRPIon)

Wake On Wireless LAN!

Put simply it triggers a high value to a GPIO pin of your choice when a HTTP POST request is sent to the listening IP and TCP port.

Just what I wanted for a simple RPi Zero W to control a single 5v relay to turn on my PC remotely.

How does it work

The Node.js program uses and Express web server to listen on port 3000. You can communicate with this from your browser using a GET. Using a browser you'll get a simple form that expects the token and the action you require to be submitted. So you can trigger the GPIO port from any browser on a phone or tablet - you just need to know the token.

But the real power is to drive it to trigger the GPIO pin you need to use a POST command and send 'application/JSON' in the with the secret token in the form { "token" : "supersecretkey" }. This will set the default GPIO pin 21 value to 1 for .5 second, long enough to trip the relay and provide the momentary connection to power on your PC using the motherboard jumper connection for your power button.

You can use IFTTT.com's web request to trigger this for you by putting the json token into the "Body (optional)" or you can use curl.

$ curl -H "Content-Type: application/json" -X POST -d '{ "token" : "supersecretkey" }' http://[IPADDRESS]:3000/api

API Actions

Beyond the initial toggle power on/off I've added the ability to force a shutdown. A regular power toggle is a .5 second activation of the power switch relay. A forced shutdown holds the relay for 10.5 seconds.

API JSON

{
  "token" : "supersecretkey",
  "action" : "on|off|force"
}

action	Description
on	Activate power relay for 0.5 second
off	Activate power relay for 0.5 second
force	Activate power relay for 10.5 seconds

Installation

You'll need to have connected your Pi to your LAN and installed git and Node.js

Clone the project to your Pi using

$ git clone git@github.com:warlord0/scorpion.git

Install the prerequisites using:

$ cd scorpion
$ npm i

Run the program using:

$ npm start

NOTE: The user you run this as must be able to access the GPIO pins. Usually root can do this, so you could use $ sudo npm start to make it work. But if you're going to run it with non-root permissions you need to make your user a member of the gpio group and re-login:

$ sudo usermod -aG gpio $USER

Running as a Service

You can run the program as a Linux service under systemd. I've included an example unit file that you'll need to edit to match your setup.

Edit the file scorpion.service.example and change the options for [PATH] and [USER] to match where you installed/cloned the program to and what user has permission to run it.

Then copy the example file to /etc/systemd/system/scorpion.service, enable it to start on boot and then start the service.

$ sudo cp scorpion.service.example /etc/systemd/system/scorpion.service
$ sudo systemctl enable scorpion.service
$ sudo systemctl start scorpion.service

Configuration

Change your token by creating a .env file in the same folder as the index.js program. Add in:

TOKEN=myownsecret

Then when you start the program you'll need to pass your own token rather than the default.

Checking Status of the Target Host

By using a tcp ping to an IP host it is able to determine if the target host is active. If it successfully connects to the target ip on the specified tcp port then you will see in the web GUI the switch for status will change to show that it is on.

I recommend you set the target port to something you know is open. Port 445 is the port used by a Windows hosts for networking so by using the .env config settings:

TARGETIP=192.168.0.1
TARGETPORT=445

The program will attempt to connect to port 445 on the specified IP. If you're using a *nix host you might want to use another port like 22 or 80.

If you leave the port at the default of 0 (zero) then no pinging will take place.

Other .env Settings

IP=0.0.0.0          # By default we'll listen on all IPv4 interfaces
PORT=3000           # By default we'll listen on TCP port 3000
GPIO=21             # By default we'll trigger the relay on GPIO 21 (BCM)
TARGETIP=127.0.0.1  # Ping the target to see if it's alive
TARGETPORT=0        # If >0 ping the target to see if the port is open
DEBUG=false         # Outputs console messages when set to true

But why?

As you can't use the Wake On LAN feature if you have a Wifi connected PC I wanted something I could use to remotely power it on. I could use a smart home socket, but where's the fun in that?

A friend setup his PC to power on using a RPi and Amazon Alexa using a combination of tasks and features of WiringPi. I wanted something more in my field of expertise - Node.js and the Google Assistant (Home).

By using a Pi Zero W I have the benefit of connecting it to my Wireless LAN and powering it from my dormant PC's USB socket - so no other mains required. Then just use IFTTT or VPN into my home LAN or use my mobile phone at home and power on my PC from anywhere.

Using a Pi Zero W means I don't have a HAT or a USB dongle providing Wifi - so nothing clutters the header pins or sticks out from the Pi other than the USB power.

The Hardware

Raspberry PI - Zero W or any Pi you have on your home LAN
5v 1-Channel Relay Module

Connections

Pinouts

RPi pin	Name	Relay
2	5V	+ (IN)
39	GND	- (GND)
40	GPIO21	VCC

PC	Relay
+	COM (Common) 常用
-	NO (Normally Open) 常开

IFTTT.com

Configuring IFTTT.com is relatively easy. Configure an "If this+" for the Google Assistant on whatever single phrase you'd like eg. When I say "Turn on my PC", have it trigger a "that+" event for a "Webhook"

Set the URL of the webhook to point to your external IP address or dynamic DNS address on the port you have forwarded to your Pi (default: 3000) eg.

Make a Web Request
URL
http://[myexternalladdress]:3000/api
Method
POST
Content Type
application/json
Body (optional)*
{ "token" : "supersecretkey", "action" : "on" }

* Not optional

warlord0/scorpion