Friday 27 November 2015

How to set up Cloak VPN on your Asus RT or DD-WRT router using OpenVPN

Hey all!
I was quite surprised today at how little information there is out there on how to configure Cloak on non-apple devices, so I thought I'd do a little write-up to save everyone the hour or two it took me to gather all this information myself. For me, the reason I need Cloak on my router is so that I can watch American Netflix on my Chromecast (and future Apple TV hehe).

Cloak is a great VPN service that's geared towards Apple products, but its official support is limited to ONLY iOS and OSX devices, with no indication of future support of other systems (so if you want a VPN android or windows support have a look at services like ExpressVPN). on the OSX client it uses an OpenVPN profile with the following configuration (don't worry if this makes no sense):

/Applications/ --client --daemon cloak --writepid /var/run/ --log-append /var/log/cloak.log --dev tun --lport 0 --comp-lzo --ca /.../cloakca --remote-cert-tls server --ifconfig-noexec --route-noexec --server-poll-timeout 10 --auth-user-pass --auth-nocache --auth-retry interact --management /.../cloakmgt.unix --management-client --management-query-passwords --up-delay --up-restart --plugin /Applications/ --script-security 0 --verb 2 --setenv cloak_logging_uid UID --setenv cloak_plugin_server /.../cloak.pluginserver --remote ENDPOINT_1 443 tcp --remote ENDPOINT_1 443 udp --remote ENDPOINT_2 443 tcp --remote ENDPOINT_2 443 udp --remote ENDPOINT_3 443 tcp --remote ENDPOINT_3 443 udp --remote 443 tcp --remote 443 udp
And after some googling i found a gist written by davepeck (one of the guys from Cloak) that specified an OpenVPN config file for using with cloak here Awesome! But it didn't work for me :(

Nov 27 10:28:09 rc_service: waitting "start_vpnclient1" via udhcpc ...
Nov 27 10:28:10 openvpn[726]: Options error: You must define CA file (--ca) or CA path (--capath)
Nov 27 10:28:10 openvpn[726]: Use --help for more information.
So I did some playing around with the config file and eventually I got one working for me, here is where to download it  (I uncommented one line)

So here are the full instructions:

Get your router:

This is my Asus RT-AC67U. It's a fast, powerful router with a great UI (and I got it for free from work!)

Update your router firmware

Add a new VPN Client Profile
Upload the OpenVPN configuration settings provided in my gist here
Tick Import the CA file or edit the .ovpn file manually." and copy the CA from the file (including the start and finish lines) into the CA field

Click OK and Activate the VPN profile.

If everything went well, you should be exiting out of the closest exit node (in my case, Melbourne)

Now, here's where things get hacky...

Update the openVPN server in the config

If you want to exit through another country, you have to activate cloak on another device, and then resolve the domain to get the ip address of the exit node then replace the instances of with that IP. Yes, this seems like a pretty silly hack but it totally worked for me! I can't guarantee the stability of this but it's lasted me a few hours.

Now I have a portal to california, I'm free to browse the internet anonymously and American Netflix on my Chromecast!

Monday 17 August 2015

Experimenting with soluble support materials

The main reason we wanted to have dual extrduers was to enable the printing of complex structures using a soluble support material. The materials we have been using are HIPS and ABS.  HIPS (High Impact Polystyrene) can be dissolved in Limonene, a cyclic terpene made from the leftover pulp and rind of oranges.

The first design which made use of the soluble support material was a simple gear mesh test found here on Thingiverse. The print turned out functional, but the gears had a lot of freeplay and wasn't a great example of what I believed the printer was capable of.

I wanted something challenging to print, I settled on designing a bearing, specifically a roller bearing, this suited a first design as it is relatively easy to design and print compared to a ball bearing. Using information learned from an MIT Fundamentals of Design pdf on bearings I wrote an OpenSCAD script to generate a roller bearing design given desired inner and outer diameters, you can find the script on my github.

The design went through a couple of iterations, this first version I printed had a very small gap between the inner and outer side walls, this made it very difficult to get the soluble support material out.

Below is the latest render of the bearing without the outer wall to show the internal workings, in this iteration the gap between the inner and outer sidewalls has been increased to allow more liquid flow into the internals of the bearing. The ring running through the center of the rollers is the cage, this keeps the rollers spaced correctly.

For the first print I generated more support material than needed, I rectified this and below you can see a render of the support structure less the outer wall support. One of the biggest reduction in disolving time is to adjust the slicing settings for the soluble support I used slic3r with the following settings: 
    For soluble support:
        -Extruder                       soluble material (HIPS)
        -Top solid layers                      1
        -Solid bottom layers                0
        -Perimeters                                 0
        -Solid infill threashold area   1mm^2 
    For bearing:
        -Extruder                                   solid material (ABS)
        -Top solid layers                     3
        -Solid bottom layers               3
        -Perimeters                               5
The removal of unnecessary support and adjustment of slicing settings keeps the amount of material to be dissolved as minimal as possible and saves on your dissolving fluid.

The final print is dissolved in limonene, it took quite some time to dissolve the support but in the end A couple of the rollers were still stuck. In the process of trying to work them loose one of the rollers snapped in half at the cage so I will be reprinting again. It can handle a filament spool but I don't think it would survive at anything but slow speeds.

See here for the design on thingiverse or on my github.

I might try redesigning the cage in the future, in replace of the single cage there would be a cage either end of the rollers. This would make the support material between the roller and cage easier to dissolve. However it has a couple of downsides, it will mean more support material to support a second cage and restrict the side openings.


Monday 10 August 2015

The Hydra: a Dual Head i3-Based 3D Printer

Laserphile's most extensive project so far has to be our 3D printer, dubbed The Hydra. The Hydra evolved naturally from it's ancestor, the Prusa i3 which we have modified and tinkered with for 2 years to get to where we are now. Although still under development it's a fast, thermally efficient, dual head printer with a custom, laser-cut acrylic case and uses the Bowden mechanism for extrusion. Here's a run down of the process we went through to get to where we are now.



Using the designs of the Prusa i3, created by Josef Prusa we had the aluminium frame cut using an industrial water jet cutter and sourced as much of the electronics and hardware from local stores. Altronics had all the cabling, the arduino micro, various electronics and a small selection of nuts and bolts. The smooth and threaded rods came from various local hardware stores.

Once we had gathered all the pieces together, the printer came together really quickly. Within a few hours we had assembled most of the printer, and we had an awesome 3-axis robot that moved around with serial commands within a few days.


After finishing construction we had some issues relating to the reliability of prints, namely getting prints to stick to the heated bed. We mitigated this by increasing the temperature of the heat bed, this was helped by insulating the underside of the bed with styrofoam wrapped in Aluminium foil to decrease thermal losses and adding a layer of Kapton tape to the print surface to increase the print adhesion. This worked great but after some months of use we found the heated bed (which is essentially just a fibreglass circuit board) had started to warp, so we decided to splash out and get a piece of glass cut (actually only cost $5 from a local glass cutter). Having the glass made a world of difference, it made levelling the print bed much easier and the build surface was now perfectly flat. No more would prints fail to stick!


Our printer management software of choice has been Octoprint which runs on our Raspberry Pi and provides an excellent graphical interface to the Arduino micro controller using a web server. You can upload your gCode files to it and initiate prints along with the ability to manually control temperatures and movement, very useful for calibration. In the photo below you can see the raspberryPi mounted on the right hand side of the frame.

Bowden Extruder

Now that we had unlocked the "relatively stable print quality" achievement with our mostly vanilla i3, we really started to tinker with things. The fist major deviation from the i3 blueprint came with our implementation of a bowden extruder, it was a huge upgrade to our heavy, direct drive extruder that was causing a lot of backlash on the X axis. The first extruder we used was a slightly modified QU-BD MBE V9 direct drive extruder which we turned into a bowden setup with a few custom parts, later on we switched to E3D V6 hotends and re-designed our own bowden motor mount. The different designs for the motor mount can be found in this repository.
QU-BD direct drive extruder
QU-BD bowden extruder
E3d V6 hot end

Two heads are better than one

By far the biggest upgrade we have done to the printer is add a second extruder to it. This allows it to do a few extra things that are just impossible with a single extruder, first it can do two colours (see below) and it can do different plastic types. The main reason for the upgrade is so it can print with a soluble support plastic along with the normal plastic, this opens up a realm of possibilities.

Laserphile Hydra dual head extruder systemLaserphile Hydra 3D printed dice with multiple materials

Acrylic Case

Our most recent mod is probably our most unique. Although our cider box thermal solution was actually pretty effective, to further combat the issues we had with warping we designed an acrylic case to try and retain some of the heat from the heated bed and block any draughts. Although it took a while to refine the design using Open SCAD, it was really surprising how easily this case came together after we got the pieces laser cut. You can find the design files here.

Laserphile Hydra 3D printer with cardboard case
Laserphile Hydra with custom acrylic case

The Future

Our plan is to continue to work on improving the print reliability, and increasing the z axis print height. This will require modifications to the heat bed mount and hot end mounts as these are the parts most vulnerable to vibrations and effect the print height.
Laserphile Hydra 3D printer on desk
Printer desk

I recently designed and printed a roller bearing to be printed in one piece and then the support material holding the rollers in place can be dissolved away to create a working bearing. I'll discuss this in a future post.


Saturday 11 April 2015

Bluetooth DMX controller update

After a couple of queries from people interested in this project i have decided to post an update to what we have been working on. We have produced a production prototype of the Bluetooth DMX controller to bring it a step closer to being ready for a small run production sample. I also threw together a very basic Android application using MITs application inventor, this let us test the first prototype as well as show off the proof of concept to friends.

The hardware

There were a couple of design iterations building up to the construction of the first production prototype. The production prototype boards are based around an Arduino mini controller and a Roving Networks RN-42 SMD bluetooth module.

The component list in full:
  • Arduino mini
  • RN-42 SMD bluetooth module
  • MAX485 RS-485 serial interface
  • 5V TO-220 regulator
  • 3.3V TO-220 regulator
  • 3 * 10µF electrolytic capacitors
  • 2.5mm barrel jack power connector

You can see the component layout in this early design revision. from the right most side we have the XLR connector, the 8 pin MAX485 IC, the 5v regulator with capacitor above, socket layout for the arduino mini, surface mount pad layout for the RN-42 bluetooth module, 3.3v regulator, two capacitors and the 2.5mm barrel jack power connector. Note that all the thru-hole components are on the non copper side and the bluetooth SMD module is soldered straight onto the copper side of the printed circuit board.

The following is the layout of the first unit built, it has the power components all to the right hand side of the board to simplify the track layout, and have both power and DMX connectors coming out the one end.

For production the design is transferred to a Kinsten positive photo resist board by covering the bare circuit board with the printed design (printed on transparency paper) and exposing it to UV light, in our case using a specially designed UV flruo lightbox. After exposure the baord is still sensitive to light so it must be quickly developed in the Kinsten developer solution. Finally it is ready to etch, I did this using Ferric chloride and an old electric stove in an open area (the fumes can be quite noxious). Last two steps are to give the etched board a coat of circuit board lacquer to prevent the copper oxidising in the air and drilling out the holes for components.

You can just see 4 identical circuits laid out on the large circuit board on the table.

The first constructed prototype.

The current hardware plan is to make a small production run of units with 3d printed cases. We will give these units out to friends so we can get some feedback on what could be changed.

The Android software

The Android software is currently very basic, being able to only address 5 DMX channels via sliders on the touch screen. I built this quickly using the MIT app inventor, a very useful tool for quickly and easily making android applications.
I set up the first 2 channels to be able to strobe between 0 and the selected value on the slider (maximum 255).

I plan on re-writing the application from scratch and will be working to add the ability to assign a group of DMX channels to individual devices (like multi colour LED lights or moving heads). This will allow for a simple and intuitive interface for any screen size.
Following that I will work on enabling the ability to pre-set scenes and animations to be enabled on cue or run on a pre-set timeline.This will bring the functionality of the control software to be on par or better than low end dedicated DMX lighting desks.

Stay tuned.