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Automatic Software In The Loop (SITL) setup for ArduPilot

For those who use and develop using the ArduPilot autopilot software (as featured on DiyDrones and ArduPilot Discourse), a powerful simulation tool is available that can replicate all of the features of the autopilot without flying an actual aircraft. This is extremely useful for testing complex missions or parameter configurations without risking real hardware.

Flying a simulated ArduPlane UAV around Canberra from the comfort of my desk in Perth.
Flying a simulated ArduPlane UAV around Canberra from the comfort of my desk in Perth.

Unfortunately setting it up is a bit tricky, official instructions are available however to make life easier I have created an automatic script that you can run that will install and run the SITL software on a Ubuntu 14.04 Linux PC or virtual machine.

This software is licensed under GNU General Public License version 3 and the source code is available at

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Download all attachments from Trello card as a zip file

Trello is amazing tool for co-ordination, planning and collaboration with the ability to assign cards, create due dates and checklists and also attach files. I have often found myself wanting to download all of the files associated with a card but have not found an easy way to do this without manually clicking and downloading on each one.

To simplify this I’ve created an online attachment downloading tool that you can export your card information to and it will create a single zip file of all attachments on the card:

Trello Attachment Downloader

Apache as reverse proxy for letsencrypt free https certificates


You have a single incoming IP address and want to run multiple web servers for multiple sites behind this IP address on your local network. The best way to do this is using a reverse proxy server For example:

  • Your External IP is: with and internal LAN of 10.1.1.X
  • Ports 80 (http) and 443 (https) have been forwarded from your external ip to an internal server at which will handle the reverse proxy and SSL/TLS work using letsencrypt
  • You have other application web servers listening on port 80 on your internal LAN at and but these are not accessible from outside your network.
  • You have and both pointed to and you want visitors to them to see the application servers at and respectively.
  • You want to provide secure https access to both subdomains but don’t want to configure this on each of the three servers separately.

This guide is based on using Apache2 on Ubuntu 16.04, some commands may differ slightly between different flavours of Linux but the core configuration for Apache2 should work on any distribution.

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Simple set up for Turnigy 9XR (or similar) 6 position mode switching with APM Autopilots – No Hardware/Flashing Required

This is a cross post for one of my original blog posts on DIY Drones. It is included here for permanent reference.


Until recently my main TX was a Turnigy 9X and I (like many others) was using a hacked in 6 position POT switch to select modes on my various aircraft. Unfortunately the 9X has died so has been replaced by a shiny new 9XR. Rather then hack apart the 9XR (too pretty) I wanted to experiment with using the existing controls to select modes on my aircraft. I have seen several tutorials on this but none met all of my requirements below.

  1. Not relying on guessing the position of the continuous POT switches
  2. Gives a easy to read visual indicator of current mode
  3. Uses only a single radio channel
  4. All performed with the default software and hardware – no flashing/hacking required

The method I used was to combine the 3 position switch (ID0/1/2) with the Aileron Dir switch. Between these two switches there are six possible combinations which neatly matches the 6 modes of the APM ecosystem.

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Team West Coast UAV in the 2016 Medical Express UAV Challenge

One of my passions is UAVs or drones of which I’ve built a number. Over the past year I’ve been working with a local team of fellow enthusiasts preparing an entry for the 2016 UAV Medical Express Challenge.

The competition involves a simulated scenario where teams must send an unmanned, autonomous aircraft a substantial distance (10-30km) away to locate a person who is unwell. Once located, an aircraft must land near the unwell individual and a blood sample will be placed in the aircraft. Next, the aircraft must autonomously take-off and return back to the launch site where that sample would be “tested” to help diagnose and treat the simulated casualty.

In September 2016 we received a “go” decision from the judges to proceed to Deliverable 2 where we must demonstrate our capability to complete the challenge. We submitted this yesterday and from here the judges will short-list the 20 teams that will get to attempt Deliverable 3 and enter the competition.

Our team blog contains the full details from Deliverable 2 including the written report and the accompanying video is below:

This challenge is an exciting opportunity to demonstrate the abilities of technology for doing good in our world. The fact we can develop this on tiny budgets with a DIY approach is a real testament to the amazing world we all live in.



I run a Tor Exit Relay (and so should you)

We’re all being monitored online in some way – that’s no surprise or secret. Many of us, myself included are not particularly concerned about this for most day to day things. We might not be doing anything “wrong” by the laws of our country so we go about our online business without much of a second thought.
For many people around the world this is not the case. Numerous governments create environments where online freedom is curtailed and censorship rules. They may restrict access to news, communication tools or even specific topics by keyword and will often punish people who attempt to access such information.

For the last few months I’ve been experimenting with hosting Tor relays on some virtual private servers across the internet as a way of helping to provide channels for people to access information and communicate more freely.

The status screen for one of my exit relays showing a solid 40-50Mbit/sec a second of traffic passing through it.

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Don’t throw it away – the future of spaceflight

An economist would ask the question; what is the price elasticity of the orbital space launch market? In simpler terms – what could the impact of space launch costs reducing but as much as 75% do to the commercial space industry.


For my thoughts I want to take you back in time to some quotes in the early days of a new technical development:


“The Americans have need of the telephone, but we do not. We have plenty of messenger boys.”
Sir William Preece, chief engineer of the British Post Office, 1876

“Television won’t be able to hold on to any market it captures after the first six months. People will soon get tired of staring at a plywood box every night.”
Darryl Zanuck, 20th Century Fox, 1946

“There is no reason anyone would want a computer in their home.”
Ken Olson, President of Digital Equipment Corp 1977


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Jack of many trades and decent at some!

So what motivated an IT guy turned management consultant to start a blog without any central theme to hold it together?

Of course this being my blog that’s a rhetorical question. I’ve always thought of sharing more about my various projects as well as my thoughts about various things that affect us all so here we go!


You can expect to hear from me on a variety of topics:

I have built at least four different autonomous aircraft and am part of the WestCoastUAV team in the 2016 Medical Express Challenge.

My Talon aircraft during testing for the 2016 Medical Express Challenge

Space Exploration
Alas I do not own any spacecraft yet but my beautiful girlfriend gave me an awesome telescope for my Birthday this year and I’ve always had a lot of enthusiasm for space exploration.

The Moon
Holding a phone up to the telescope – arranging a proper way to capture images will probably be a future post once I figure it out.

I am passionate about how technology can change our world for the better. I am most definitely an advocate in favour of privacy and encryption andto back this up I operate a tor exit node on a VPS to help improve the availability of private and secure communications on the internet for those that need it.

This is my day job but I am fortunate enough to be at the centre of some major transformation projects and where appropriate will look to share some insights here.


That will about do for now. Of course there is every possibility I’ll actually end up posting something completely unrelated and you can expect I’ll take things where my mind goes which should keep things fresh!