VPN Light Switch

Red LED - VPN Disabled

Purple LED - VPN Init

Green LED - VPN Enabled

Blue LED - VPN Standby (inactive)

Updated init.lua for the PCB with the Osram LED:

function vpnconnect ()
  conn=net.createConnection(net.TCP, 0)
  conn:on("receive", function(sck, c)
    if string.find(c,"CONNECTED") then
      print("Connected")
      state = 1
      gpio.write(5, gpio.HIGH) --RED
      gpio.write(6, gpio.LOW) --GREEN
      gpio.write(7, gpio.HIGH) --BLUE
    end
    if string.find(c,"RECONNECTING") then
      print("Standby")
      gpio.write(5, gpio.HIGH) --RED
      gpio.write(6, gpio.HIGH) --GREEN
      gpio.write(7, gpio.LOW) --BLUE
      state = 0
    end
    if string.find(c,"AUTH") then
      print("Auth")
      state = 1
      gpio.write(5, gpio.LOW) --RED
      gpio.write(6, gpio.HIGH) --GREEN
      gpio.write(7, gpio.LOW) --BLUE
    end
    end
  )
  conn:on("disconnection", function(sck, c)
    print("VPN Disabled")
    gpio.write(5, gpio.LOW) --RED
    gpio.write(6, gpio.HIGH) --GREEN
    gpio.write(7, gpio.HIGH) --BLUE
    connected = 0
    end
  )
end


function buttonpress (level)
  if triggered == 0 then
    if level == 0 then
      if connected == 1 then
        triggered = 1
        tmr.alarm(1, 200, 0, function() --debounce delay
          if state == 0 then
            conn:send("hold off\r\n hold release\r\n")
            state = 1
          else
            conn:send("hold on\r\n signal SIGHUP\r\n")
            state = 0
          end
          triggered = 0
          end
        )
      end
    end
  end
end


--Don't forget to associate with AP with (once off) commands:
--wifi.setmode(wifi.STATION)
--wifi.sta.config("accesspointname","yourpassword")
--wifi.sta.connect()
--print(wifi.sta.status()) <--5 means associated
--print(wifi.sta.getip())


gpio.mode(4,gpio.INT)
gpio.mode(5, gpio.OUTPUT) --RED
gpio.mode(6, gpio.OUTPUT) --GREEN
gpio.mode(7, gpio.OUTPUT) --BLUE

--Set output low to turn on LED
gpio.write(5, gpio.LOW) --RED
gpio.write(6, gpio.HIGH) --GREEN
gpio.write(7, gpio.HIGH) --BLUE


connected = 0
state = 0
triggered = 0


gpio.trig(4, "down", buttonpress)


tmr.alarm(0, 1000, 1, function()
  if connected == 0 then
    vpnconnect()
    conn:connect(7505,"192.168.1.1")
    connected = 1
  end
  if connected == 1 then
    conn:send("state\r\n")
  end
  end
) 

PCBs have arrived. Just waiting on some more ESP8266 modules.

You can now order 3 of the PCBs from OSHPark for $4.90!:

https://oshpark.com/shared_projects/IvtIc9f2

The bill of materials is as follows:

Part Value         Device        Package     Description                   
C1   0.1uF Ceramic C-EUC0805     C0805       CAPACITOR, EU symbol    
C2   22uF Tantalum C-EUC0805     C0805       CAPACITOR, EU symbol    
JP1  2.54mm        PINHD-1X2     1X02        PIN HEADER                    
JP2  2.54mm        PINHD-1X3     1X03        PIN HEADER                    
JP3  2.54mm        PINHD-1X2     1X02        PIN HEADER                    
LED1 GM5WA94310A   GM5WA94310A   GM5WA94310A Chip LED RGB                  
R1   Blue LED      R-EU_R0805    R0805       RESISTOR, EU symbol     
R2   Red LED       R-EU_R0805    R0805       RESISTOR, EU symbol     
R3   Green LED     R-EU_R0805    R0805       RESISTOR, EU symbol     
R4   10K           R-EU_R0805    R0805       RESISTOR, EU symbol     
R5   100Ohm        R-EU_R0805    R0805       RESISTOR, EU symbol     
S1   SKHMPSE010    TACT Switch   SKHMPXE010  6.2X6.5mm 
ESP  ESP8266       ESP8266       ESP-03      ESP8266 Wifi module  
U1   MIC5209-3.3YS MIC5209-3.3YS SOT223      LDO REGULATOR

You will need to pick R1,2,3 to suit the LED you order as this can change. Please see the datasheet of the LED when ordering. The power supply is 3.3V.

With the MIC5209-3.3YS regulator you can have an input voltage of 3.3V to 16V and it has reverse input voltage protection (the regulator shuts off safely)!

Update:

It turns out the GM5WA94310A LED is obselete, as is the SKHMPSE010. Suitable replacements for these are:

Osram Opto LRTB GFTM - http://docs-europe.electrocomponents.com/webdocs/0e24/0900766b80e2426e.pdf

APEM DTSM644RV - http://docs-europe.electrocomponents.com/webdocs/0642/0900766b80642d5a.pdf

If using the Osram Opto, appropriate resistors are (note the designations have changed too):

R1   Red  LED      R-EU_R0805    R0805       RESISTOR, EU symbol, 47ohm     
R2   Green LED     R-EU_R0805    R0805       RESISTOR, EU symbol, 6.8ohm     
R3   Blue LED      R-EU_R0805    R0805       RESISTOR, EU symbol, 22ohms

I'll soon have these made up and tested. It also doubles as an all purpose no purpose ESP board. The board itself is 1"x1" so you can order three of them from OSHPark for $5 including shipping.

In this video I test the LED and button operation in two separate steps. This is testing the LUA code and is completely functional.

Unfortunately, as there are limited GPIO pins on the ESP01 module, when testing the buttons, I disable one of the LEDs.

Once I break out some more GPIO pins from the module, I will finalise the code to perform as per the state machine.

Here is some code to monitor the status of the VPN server. The RGB LEDs are common anode, with the anode connected to 3.3V (and a 100Ohm resistor on each leg connected to GPIO). The ESP module sinks the current:

LED on - gpio.write(3, gpio.LOW)
LED off - gpio.write(3, gpio.HIGH)

Unfortunately because the ESP01 module only has two GPIOs, it is difficult to add both button and LED functionality at the same time. I will break these connections out later. But for the moment, the button is connected to GPIO 3 and the LED to GPIO 4.

The button is connected as follows:

                         VCC                  
                        +-+-+                 
                          |                   
                          |                   
                        +-+-+                 
                        |   |                 
                        |10K|                 
                        |   |                 
                        +-+-+                 
                          |                   
                          |                   
           +-------+      |                   
GPIO ------+  100  +------+                   
           +-------+      |                   
                          +                   
                           \  Switch          
                            \                 
                          +                   
                          |                   
                        +---+                 
                         +-+                  
                          +                   
                         GND

The code:

function vpnconnect () 
  conn=net.createConnection(net.TCP, 0) 
  conn:on("receive", function(sck, c) 
    if string.find(c,"CONNECTED") then 
      print("Connected") 
      state = 1 
	  --gpio.write(3, gpio.HIGH)
      gpio.write(4, gpio.LOW) 
    end 
    if string.find(c,"RECONNECTING") then 
      print("Standby") 
	  --gpio.write(3, gpio.HIGH) 
	  gpio.write(4, gpio.HIGH)
      state = 0 
    end 
    if string.find(c,"AUTH") then 
      print("Auth") 
      state = 1 
	  --gpio.write(3, gpio.LOW) 
      gpio.write(4, gpio.LOW) 
    end 
    end 
  ) 
  conn:on("disconnection", function(sck, c) 
    print("VPN Disabled") 
	--gpio.write(3, gpio.LOW) 
    gpio.write(4, gpio.HIGH) 
    connected = 0 
    end 
  ) 
end 

function buttonpress (level) 
  if triggered == 0 then 
    if level == 0 then 
      if connected == 1 then 
        triggered = 1 
        tmr.alarm(1, 200, 0, function() --debounce delay 
          if state == 0 then 
            conn:send("hold off\r\n hold release\r\n") 
            state = 1 
          else 
            conn:send("hold on\r\n signal SIGHUP\r\n") 
            state = 0 
          end 
          triggered = 0 
          end 
        ) 
      end 
    end 
  end 
end 

--Currently using GPIO3 as button, all LED references commented out
--gpio.mode(3, gpio.OUTPUT) 
gpio.mode(3,gpio.INT) 
gpio.mode(4, gpio.OUTPUT) 

connected = 0 
state = 0 
triggered = 0 

gpio.trig(3, "down", buttonpress)

tmr.alarm(0, 1000, 1, function() 
  if connected == 0 then 
    vpnconnect() 
    conn:connect(7505,"192.168.1.1") 
    connected = 1 
  end 
  if connected == 1 then 
    conn:send("state\r\n") 
  end 
  end 
) 

Note that when the VPN is in "standby", the service is still running, it just changes the IP tables so the VPN is no longer used. The service daemon will report that it is still running.

You can use LuaLoader to save the file to the ESP module so it runs on boot.

To stop it while testing just run:

tmr.stop(0)
conn:close() 

Here is a link to the NodeMCU firmware - https://github.com/nodemcu/nodemcu-firmware

You can build this with the ESP toolchain (instructions on building the toolchain here). You can also use the NodeMCU flasher which has prebuilt firmware included - https://github.com/nodemcu/nodemcu-flasher

To connect to a telnet session and send/receive, you can use the following using the socket library:

conn=net.createConnection(net.TCP, false)
conn:on("receive", function(sck, c) print(c) end )
conn:connect(7505,"192.168.1.1")
local ok, err = conn:send("state\n")
conn:close()

Using an OpenVPN daemon (on a WRT based router for example) with the following added to the config file, you can monitor the VPN status and control it (once the service has started):

management 192.168.1.1 7505

If the service hasn't started, the LED will be red, indicating it needs to be started manually (via the router's web GUI for example). Once it is up and running however, it can easily be controlled via a telnet connection to port 7505.