Category Archives: Uncategorized

Capture your Mac screen activity into daily videos

Screenshot 2015-05-26 14.42.37I know I’m not alone in wishing there was a TimeSnapper equivalent for the Mac.  Among many things it lets you look back in time at what you were doing on your computer minutes, hours or days ago.

Perfect for remembering what you were doing yesterday, and even to recover stuff that was displayed on your screen.

Inspired by TimeSnapper, I’ve created a small bash script that I’ve called MacBlackBox which takes regular screen-shots every few seconds. Every hour it combines the screenshots into an mp4 video, and every day it combines the hourly videos into daily videos, one per screen.

It is available in GitHub here.  Happy to accept improvement suggestions.

Keeping your Moto 360 alive while charging


If you are developing using the Moto 360 and debugging over bluetooth, you’ll notice the battery plummeting quickly.

If you put the watch on a QI charging pad, the Moto 360’s charging screen kicks in, and you can no longer do anything on the watch, although if you launch your app via Android Studio, it will run.

If you still want to use your watch while it is charging, root it, and disable Motorola Connect on the watch using:

adb -s 'localhost:4444' shell
$ su
# pm disable com.motorola.targetnotif

This works for me, although I am sure it stops plenty of other things from working, so only do this on a development device, and at your own risk.

Ski Goggles and Sick Bags: The past, present and future of Virtual Reality

imageimageNote: This is derived from a speech I gave at toastmasters last week, inspired by the arrival of my very own brand new Oculus Rift VR headset




A generation inspired.

In 1984 the author William Gibson penned his first book, called Neuromancer, and inspired a generation.

In it the protagonist navigates through cyberspace.

If you don’t know what cyberspace means, you are not alone.  At the time that William Gibson wrote Neuromancer, nobody else knew what it meant either.  He invented the term.

Cyberspace in that book was a virtual reality.  An immersive computer generated world which when you are in it, feels just like the real thing, beamed directly to the brain via a neural interface.

Our imaginations were fired.  We wanted it so badly.  Looking back, I’m not even sure why, but man was it cool.

There was no way anything like it was possible then.  A personal computer could barely output color, let alone create that kind of world.

Dreams dashed

Time passed, and by the 1990s my generation still hadn’t forgotten the dream of Neuromancer.  Computers and computer graphics were getting more and more powerful. 

You even started to see video arcades with games with virtual reality headsets.  I still remember the day I tried one on, sickly smell of cigarette smoke, music from the arcade games pouring in my ears, almost as loud as the pounding of my heart.  This was it, I was going to experience Virtual Reality.  I placed the headset on my head, and looked around as it projected images into my eyes.

The disappointment was devastating. Not only did it feel like I was wearing a dustbin on my head, it was so clumsy and heavy, but the experience was terrible too.  Clunky objects drawn as outlines, which struggled to be re-drawn as I over my head around.

The virtual reality dreams of a generation were dashed on those arcades, as I and many others consigned the idea of virtual reality to the dustbin.

A new hope

Time passed.  Whole new business sprang up, such as Amazon.  Not only did new business spring up, but new ways of doing business sprang up too.

In the old days if you had an idea for a hardware product, such as some kind of electronic gadget you’d need to go to a big company to get it funded.  Endless bureaucracy and meetings.  You’d likely have to give up the rights to your product, and compromise your soul in order to get something like your idea to market.

But the internet and the world wide web changed that.  Now, when someone has an idea for something, such as a new watch, they can go to sites such as Kickstarter, and pitch their idea not to a committee in a bureaucracy, but instead they can pitch their idea to the world.  They can describe what they want to make, what their experience is in the field, what it will cost to bring it to the market, and they can let thousands of individuals invest in their idea, in return for a sample of the product if it ever gets made.

The Pebble watch I’m wearing right now started on Kickstarter.  Their goal was to raise 100,000 dollars to bring it to market.  They didn’t raise 100,000 dollars.  They raised 10 million dollars.

So that’s one thing that happened”": decentralized “crowd funding” as it is called, a new way of bringing products to market.

The other thing that happened is mobile phones: Incredibly powerful miniature computers that we all carry in our pockets.  Because they are being made in massive quantities the costs of the components that go into them has dropped massively too.  And those components are interesting. 

These phones have small, but incredibly high resolution screens.  They have a vast array of sensors in them, such as gyroscopes so that they can tell when they have been turned, accelerometers to tell when they are moved, and magnetometers to tell which direction they are facing.

Can you imagine what would happen if you took those screens, attached them to some kind of a helmet, like ski goggles, included the sensors from phones to accurately track your head position, and hooked them up to a computer to generate slightly different images on each screen?  You’d have a virtual reality system. 

As it happens, someone in the states did have that idea.  Someone that knew enough about virtual reality headsets to put together a working prototype.

imageIf only they had some way to bring their idea to market.  Of course they did, and the Oculus Rift Kickstarter was a massive success.

Those that have tried them on have been astounded by the results.  It creates a truly immersive virtual reality experience.

Anyone who was wondering what value virtual reality can possibly have beyond games need only watch a 90 year old women trying them on, screaming with joy, walking around an Italian villa, leaves blowing in the wind, butterflies flittering in the air. 

There are plenty of people who for one reason or another are unable to travel, or even to move, yet they can experience the world through virtual realty. 

School kids can watch the birth of the universe, or chemical reactions happening, and step into the reaction to see it from different perspectives. 

This technology is still young.  The Oculus Rift is still not publicly available.  Its only available to software developers who wish to create for it.  But its coming.

I’ve talked about the ski goggles, but what about the sick bag?  Well all is not perfect with the Oculus Rift.  Many people report nausea after trying it on for a while.  Perhaps its the eye strain, or perhaps the image still isn’t moving quite fast enough and the body senses that. 

I’m sure that they will lick the nausea, and soon, very soon indeed, you too will be visiting new parts of our world, or even other worlds, in virtual realty.

Some good books

I was at the speaker’s dinner after speaking at the excellent Reaktor conference in Helsinki, chatting about our favorite authors, and rather than just sending an email to the people that were there, I thought I’d instead write a blog post.

Good authors are hard to find.

These are books I’ve enjoyed over the last couple of years, culled from my Audible and Kindle accounts, skipping over many many “meh” books.  Bing links brought to you courtesy of Gmail.

Changing the Windows Amazon Cloud Drive app sync folder

Amazon just released the first version of their Windows app to sync Amazon Cloud Drive.  It’s very much a first version, with no ability to pause/resume sync, sync selective folders, or even (as far as I can see) a way of changing the default sync folder.

imageWhen I displayed the options dialog, I assumed that all you had to do was click on the location to change it, but that simply opens the folder in the Explorer.

It chose the smallest drive on my machine (of course), but I found a way to change it.



Do this entirely at your own risk, and if you don’t know what this means, then don’t do it.  You can use regedit to change the sync folder’s location, under "HKEY_CURRENT_USER\Software\Amazon\AmazonCloudDrive\SyncRoot" change “SyncRoot” to a different folder.


Works for me, but no guarantees.

HTC Gingerbread–automatically switching from Wifi to costly data connection

I have an HTC Incredible S, and it’s a very nice phone indeed.

I recently upgraded Android 2.3.3 (Gingerbread), and discovered that the Wifi connection was dropping in places at home where it had a perfectly usable (albeit weak) Wifi signal.  Places where previously it had worked.

I fiddled with my Wifi base station, repositioning it, to no avail.

Finally I googled and found that HTC had decided to switch from Wifi to data if the Wifi signal dropped below a certain strength (88dbm).  How nice of them to decide on my behalf that I wanted to switch from my (free) Wifi to my (expensive) data plan, even though I still had a perfectly usable (and free) Wifi connection – one that worked perfectly well in the previous OS version.

This is annoying for a couple of reasons.  Firstly I can now run up horrendous data plan charges even though I’m within range of my Wifi.  Secondly, I have services I run on my local Wifi (IP Cams, remote control software) that can no longer connect when I’m off my Wifi.

I’ve been a big HTC fan for a long time, and have gone through many of their ‘phones.  This is a big disappointment for me – it stinks of paternalism/arrogance – deciding what is best for me without giving me a chance to override it.  I am sure that it isn’t arrogance/paternalism – I am sure it made perfectly good engineering sense, perhaps because less battery will be consumed on data than on Wifi when on a weak link, but give me a choice.

I contacted HTC support and was told that yes, this behavior is new and that no, there was no way to downgrade – the suggestion was to switch off the Data connection when I was at home. Right, as if I will remember to do that.

I’ve ended up installing Tasker, and setting up a rule to switch off my Data connection when within range of my home Wifi.  Not ideal, but it works.

Generating Silverlight / Windows Phone compatible Thrift proxies

Thrift is a software framework for scalable cross-language services development. It combines a software stack with a code generation engine to build services that work efficiently and seamlessly between C++, Java, Python, PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, Smalltalk, and OCaml.

There are two reasons for this post:

  • to float some ideas for C#changes to the Thrift development community.
  • to remind myself in the future what I need to do to download, modify and build the Windows Thrift compiler, and

The idea is to maintain backwards compatibility, whilst at the same time generating Silverlight (and consequently Windows Phone 7) compatible proxies.

There are two sets of changes.  One to the C# code generator (t_cpp_generator.cpp), and the other to the runtime files (mainly THttpClient.cs).

Downloading and building the thrift compiler

To try out these changes on Windows, first install the latest version of Cygwin from, then install the various packages as described here:

You’ll also need to install Subversion.

Next pop open the Cygwin shell, and fetch the latest source, as described here:

Finally, build the source you downloaded, again as described here:

In my environment I build using:


And then I run the new thrift compiler:


Code Generator changes

The code generator (t_cpp_generator.cpp) changes involve generating two additional methods for each “standard” method: a Begin_… method and an End_… method.

Whereas previously there might just have been a method such as this:

   1: SyncState getSyncState(string authenticationToken);

Now, two additional methods get generated:


   2: IAsyncResult Begin_getSyncState(AsyncCallback callback, object state, string authenticationToken);

   3: SyncState End_getSyncState(IAsyncResult asyncResult);

   4: #endif

The two methods allow for the asynchronous invocation of methods, using the standard .NET asynchronous invocation pattern.

In addition, the generated standard method (“getSyncState”) method is modified when building for Silverlight, to make use of the Begin… and End… methods:

   1: public SyncState getSyncState(string authenticationToken)

   2: {

   3:     #if !SILVERLIGHT

   4:     send_getSyncState(authenticationToken);

   5:     return recv_getSyncState();


   7: #else

   8:     var asyncResult = Begin_getSyncState(null, null, authenticationToken);

   9:     return End_getSyncState(asyncResult);


  11: #endif

  12: }

As you can see, when not running Silverlight the standard code path is invoked, but when running Silverlight the asynchronous methods are invoked (the End… method blocks the current thread until the Begin… method completes).  This is not something you should be doing on the UI thread.

The generated Begin… and End… methods are pretty thin:

   1: public IAsyncResult Begin_getSyncState(AsyncCallback callback, object state, string authenticationToken)

   2: {

   3:     return send_getSyncState(callback, state, authenticationToken);

   4: }


   6: public SyncState End_getSyncState(IAsyncResult asyncResult)

   7: {

   8:     oprot_.Transport.EndFlush(asyncResult);

   9:     return recv_getSyncState();

  10: }

Note the call to EndFlush above – this is one of the changes made to the runtime.  The other is invoked by the generated send_getSyncState method:


   2: public IAsyncResult send_getSyncState(AsyncCallback callback, object state, string authenticationToken)

   3: #else

   4: public void send_getSyncState(string authenticationToken)

   5: #endif

   6: {

   7:     oprot_.WriteMessageBegin(new TMessage("getSyncState", TMessageType.Call, seqid_));

   8:     getSyncState_args args = new getSyncState_args();

   9:     args.AuthenticationToken = authenticationToken;

  10:     args.Write(oprot_);

  11:     oprot_.WriteMessageEnd();


  13:     return oprot_.Transport.BeginFlush(callback, state);

  14: #else

  15:     oprot_.Transport.Flush();

  16: #endif

  17: }

The generated recv_getSyncState() has not changed.

The changes in the generated code boil down to asynchronous invocations at the transport layer (BeginFlush and EndFlush).

There are also changes to #ifdef out the Serializable attribute for generated structs, since this is not supported by Silverlight.

Runtime changes

There are minor tweaks required to THashSet, TProtocol and TBinaryProtocol because Silverlight does not support the full .NET framework API.

The main change is to TTransport.cs to introduce the BeginFlush and EndFlush methods shown above, and then to THttpClient.cs to actually implement these methods.

The existing Flush method is #ifdefed out when building using Silverlight, because it makes synchronous calls which are not supported by Silverlight.

Instead, the BeginFlush builds a request and then invokes the HttpWebRequest.BeginGetRequestStream method, passing a local GetRequestStreamCallback method as the callback.

The GetRequestStreamCallback method is invoked once the runtime has the request stream.  It then writes out the data and invokes the HttpWebRequest.BeginGetResponse method, passing a local GetResponseCallback method as callback.

The GetResponseCallback notifies the original caller (in the generated code) that the request has now completed.

The EndFlush method waits for the corresponding BeginFlush method to complete, and if there was an exception thrown at any point, it raises the corresponding exception.

The changes

The changes files are here.  If there is interest and these changes make sense, I’ll submit a patch.