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Category Archives: IT

A Raspberry Pi light switch API with Node-RED

My brother has been working on a small project to control some  Christmas lights with a Raspberry Pi. He is using the Energenie system, and followed MiniGirlGeeks python example to get things working, and set up a cron job to syncronize his four (yes four) sets of lights. He then asked for pointers on controlling them via a web page served from the Pi, and I immediately thought that Node-RED might be a great solution. I don’t have the Energenie setup, but using my Pibrella LEDs as a substiture, I thought I’d put together a quick hack to show him how it might be done.

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On Wearable computing…

I’m getting a smart watch for my birthday. It’s a big one, the birthday not the smart watch, although I’ll admit the current models aren’t the smallest arm wear ever. Ever since Android Wear and the first three Android Wear smart watches were announced, I’ve wanted one. Not because they are new technology and the latest thing, or because I want to show off. My phone is over two years old, and my tablet is even older – my tech purchases tend not to be on a whim. No, I want one because I genuinely think it will remove some pain points in my interactions with my phone, and I can see the potential for a smart watch to make my life a bit easier.

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Adventures in MQTT, MongoDB and REST – Part 2

In part 1 of my adventures in MQTT, MongoDB and REST  I described the project I’m working on in my free time, and how I want to use it to explore these technologies. In part 2, the focus will be on MongoDB, since that was really the first part of the puzzle I needed to get working. Once I have the database in place, I can start feeding it with data, and creating the API to access it.

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Adventures in MQTT, MongoDB and REST – Part 1

Unfortunately my day job doesn’t involve much of the new technology I see talked about, but  I do like to keep up where I can. Since the start of the year, in my free time I have been starting to scratch the surface of MQTT, MongoDB and REST.  I have an existing project which I’m updating, and  thought it might be worth jotting down a few thoughts as I go, probably over several posts. In this first post, I’ll cover a bit of background and outline ‘the plan’, with future posts going more technical as appropriate.

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Permanent SSH Tunnel with Better Routing

Edit Feb 2014 – after running with the new routing I discovered that after the connection dropped, the routing didn’t work properly. A quick fix is to add the local routing info into to the tunnel-check script after bringing the interface up. I haven’t investigated further yet, but I have updated the instructions to reflect this.

A while back I set up a permanent SSH tunnel between two systems on different sites to allow me to route specific internet traffic through a different external internet connection so that the traffic appears to originate from the remote site. This is useful when the source IP is used for authentication or authorisation in some way, such as for a geo-fenced application. I wrote a previous blog post on how to do that, which is here, and there were a couple of issues with managing the routing that I was never happy with. Yesterday I had cause to configure the tunnel again (using my previous post as guide of course) and this time I was determined to fix the routing.

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Real life with Windows 8

It’s been almost four months since I took the plunge and blew away my Windows 7 system and replaced it with Windows 8. I can’t remember exactly why I did it, except that I figured it would be good to get some hands on experience. Having read about but not used any of the pre-release versions, I approached the new release with an open mind, especially since I’m a real fan of Windows 7 (compared to previous Windows releases and Ubuntu). Now I’ve been using the new OS for a while I thought I’d post some some thoughts on the experience of daily use over a sustained period, compared to say initial rantings after a just a few days.

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Ode to Steve

A friend asked on Facebook which sort of tablet to go for, an iPad, Microsoft Surface or Android device. She eventually chose the iPad, and for some reason I felt inspiration to write the following.

Our Steve, who art in heaven,
hallowed be thy name.
Thy iPad come.
Thy will be done,
on Mac, as it is on iPhone.
Give us this day our daily cool,
and forgive us our patent wars,
as we forgive those who patent troll against us,
and lead us not into Microsoft,
but deliver us from Android.
For thine is the walled garden,
and the content and the app store,
for ever and ever.
Apple.

I have seen similar misappropriations of the Lords Prayer before, but not one similar to this that I recall. As far as I can tell this is my work, but it is possible something I read previously lodged in my brain and popped out at time of writing. If that’s the case I apologise. I did have a quick Google to see if I could find anything similar, but my very brief search didn’t find anything.

For the record,  I’m no Apple fan – I have two Android phones and an Android tablet – this just seemed amusing to me.

Static IP Gotcha in Ubuntu

Last week I had to re-install a small server after a file system failure, and I hit a gotcha which I always hit, and always forget about. This post is to try to ingrain it into my memory so I don’t waste time on it again.

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Permanent OpenSSH VPN with Routing on Ubuntu

*Update 29/12/2013* – I’ve written a new post on this topic with updated instructions here. I’m leaving this page as is for posterity, and I recommend you use the new post since it has (I think) better handling of routing.

I run two servers in two different locations which are connected via a permanent OpenSSH VPN, complete with routing between the two. The servers both sit on independent internet connections and I’ve implemented it so that if one side or the other drops, the connection will be automatically re-established. This means I can have some devices which route through the secure connection and access the internet through the remote end point, which can be quite useful in some situations.

Last week, one of the servers suffered severe disk corruption when power failed (no, these boxes aren’t important enough to run on a UPS), and I had to rebuild it from scratch and re-configure the permanent VPN from scratch. This was a bit of a pain the first time, and just as much the second, so I have decided to document it for posterity and (if nothing else)  future reference.

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