Determining Movement of a Distant Object on a Small Sensor

by nickw | Posted in Blog

I took a few pictures of the moon last night, which got me thinking – how many pixels on my sensor will the moon move in a specific time frame. I noticed results where I left the shutter open for more than 4 seconds, a motion blur can be seen, and anything > 1/50th of a second shows a slight elongation of the moon.

I set out to calculate this elongation; however the results weren’t great, and I know my equations are definitely wrong. The following images outline the process to determine the movement. I will return to this at a later date, and determine how to calculate the movement on a sensor.

Once completed, I found that the equation can be noted as this through the above working (although incorrect):

πS(r+a)h/43200*ø*a
Where:
ø = Horizontal angle of projection from the lens (in radians)
a = orbital altitude of object
r = radius of the earth
S = shutter time in second
h = horizontal resolution of sensor

 

iOS7 Remote Notification Removal

by nickw | Posted in Blog, Programming

I’ve noticed since the early builds of iOS7 that notification centre on both the lock screen and within the phone, now has this really nice feature.

It appears as though specific services such as Google Plus and Facebook which distribute notification to users phones will now remove the notifications from the lock screen if they have been viewed somewhere else (ie, on a computer).

A quick google search of this reveals no specific results for this phenomenon. I’m 100% sure this is a new addition to the OS, as previous builds of iOS with Facebook notifications would not be removed from your lock screen.

At the present time I am unsure of how the implementation works, however, I would assume that it would involve APNS sending a badge count of 0 to the phone, ideally removing all notifications. I will be testing this after my HSC and determining it’s results.

Smoke Pollution (Red Moon)

by nickw | Posted in Blog, Photos

Bushfire Smoke Pollution

by nickw | Posted in Blog, Photos

Microsoft Remote Desktop for Mac. It’s about time

by nickw | Posted in Blog

It’s been over 3 years since Microsoft last updated their Remote Desktop Connection client for mac. Their client was included in the Microsoft Office 2011 suite, however was available for a standalone download on their website. It worked. Not well. But it worked. It did the job, however only supported a single monitor, and wouldn’t let you quickly restore saved preferences.

Screen Shot 2013-10-19 at 7.12.36 PM

The old, Remote Desktop Connection for Mac

Finally, Microsoft have released the updated Microsoft Remote Desktop for both Mac and iOS. It’s available from the App Store. The Mac Client is fantastic. It supports all the features of the Windows client, and even has full support for more than 1 display. This means I can now utilise my 4 screens in full screen on a remote terminal session. Awesome! It has a built in saved session list, supports folder redirection and printer forwarding. Continue reading

Windows 8.1 Blue – Where’s my Standalone Upgrade

by nickw | Posted in Blog

Awesome. Windows 8.1 has been released, however, at the moment it’s only available via the Microsoft Store. This means downloading the entire 3GB upgrade on EACH computer you wish to upgrade to 8.1.

Seeing as Windows 8.1 or Blue, is ideally classified as a service pack, as it is free, why wouldn’t they create a standalone MSI? I work in a small computer shop with a connection of 10mbit/s on ADSL as it’s all we can get in our area, and to update 2 computers at once steals all the bandwidth for other tasks, and takes over 4 hours to download and complete.

Could Microsoft be channelling every new service pack into the Microsoft Store? Could this mean they may charge for future updates? Who knows. All I know is that the person who decided to not release a standalone MSI or installer for 8.1 upgrade deserves a good slap.

Closed API’s: SnapChat

by nickw | Posted in Blog, Programming

Snapchat. It’s a big craze. The point: To send photo’s that self destruct after being viewed. However; there are hacks as well as entire apps which can allow the saving of images without the sender being notified. Awesome. Hardly.

I have spent the last 2 hours finding an efficient way to reverse engineer the protocols and data being passed between the SnapChat client and the SnapChat server, in hope that I’d gain some more knowledge about how snaps are encrypted/transmitted/received by the devices. Unfortunately I have been unable to find a way to read the data in a raw format. I’ve tried both packet sniffing via WireShark, various HTTP Proxies, as well as my own Python creation. Nothing.

So now, I am writing this piece from my perspective, about how the service should work.

The service appears simple. For example;  Friend A sends a snap, the server holds this image and sends a push notification to User A’s phone, telling him/her they have an image awaiting collection. User A opens the app on their phone, SnapChat now downloads and caches all the snaps which have been awaiting collection; including Friend A’s snap.

You now have the snaps on your phone. Mods/Plugins like Phantom (iOS) simply save these cached images.

But what about other apps, like “Snap Save”? This is what I would have liked to gone into earlier. It appears the developer of Snap Save has reverse engineered the connection protocols, and mimics within it’s own app. This allows it to save the images straight to the device, instead of restricting the time limit like SnapChat does.

Could SnapChat fix this? Yes. They could.

 

Why don’t we fix it for them. Here’s how:

  1. Server generates a random string(), seeded from the current time, therefore it always changes. Let’s set up a time window, to allow these to last for ~2 minutes
  2. Server encrypts this string using a public key (KeyA). The private key(KeyA) is within the App Bundle.
  3. Server sends the encrypted string to the client
  4. Client decrypts the original random string(stringAand uses the private key (KeyA)

In the mean time, the server has done the following:

  1. Uses the original stringA
  2. Uses the secret algorithm to turn StringA into StringC

The server has now received StringB from the client

  1. Server decrypts the Encrypted StringB using KeyB
  2. Server should compare it’s own StringC  to the client’s StringB
  3. If StringC is equal to StringB, we should in theory have an authorised client.
  4. The server should now give the AuthorisedClient an access token with an expiration time or only permissions to view a specific image to limit the damage an unauthorised client could do with it (ie, saving snaps).

It’s complex, and yes, it could most definitely simpler, I am sure there are more efficient ways (lol lots of server resources) to do this, however, I have never implemented such a system, nor have I began to research this topic. This is simply how I would jump in and solve the problem.

And a quick note, this does not solve issues of plugins such as Phantom, as they hook into the SnapChat app itself.

Night trip to Helensburgh and Otford

by nickw | Posted in Blog, Photos

Liberal’s NBN & Why It Will Be Redundant In 10 Years

by nickw | Posted in Blog

Within Australia, low cost, high bandwidth internet is something we need in the future, however, the future is looking dull. The Liberal Government of Australia have now proposed a new plan to roll out a nation wide internet network for a fraction of the cost of the implementation of the NBN by the Labor Party, however, the amendments are not for the better. They are a waste.

BTj8DJLCQAA2iA9Tony Abbot’s NBN will consist of a Fibre to the Node Network (FTTN), which involves running fibre connections to ugly above ground nodes to provide for 20-30 households each. Each household will be connected to the node through existing copper connections. Within a node, switching hardware will be required, as well as modulation and demodulation hardware. Households will be using a VDSL protocol, theoretically capable of speeds up to 250mbit/s. This is fast, but will it be fast enough in 7 years when the rollout will be complete (2019)? The government only promise speeds of 25-100mbit/s by 2016 and 50-100mbit/s by 2019). The predicted cost of Liberal’s network is $30 Billion.

Labor’s NBN would have consisted of a Fibre to the Premises (FTTP) Network, which involves running fibre from Households directly to telecom exchanges. No existing copper infrastructure would be in use, and anyone on existing copper would be moved onto the NBN network for both Telephone and Internet. A fibre connection is capable of over 26Tbit/s (27262976mbit/s – more than 100000x faster than VDSL – Record set by NEC over a 50 km distance) – A connection medium more than perfect for many years to come; future-proof. Labor promised speeds of up to 1000mbit/s to be available to consumers by the end of 2013. The predicted cost of Labor’s network was $44.1 billion, $14 billion more than Liberal’s FTTN network, however, I believe, in the long run, would have been the most cost effective solution.

BTjimxeCUAEZehyThe hidden costs of running a FTTN network includes costs of maintaining the Nodes, the power usage of the nodes running switching equipment, lead acid batteries (used to provide backup power to the nodes if a power outage occurred to ensure emergency calls could still be placed) would end up in landfill after their service life, and most likely the largest cost – the ongoing maintenance of the existing Copper to the premisses to ensure a stable connection. These costs could eventually add up to the $30 billion the plan would be saving, and overall leave us with a slow, out of date, high maintenance and high cost network, and thus shows how a FTTN network is completely pointless.

Instead of running a whole new network, many households in built up areas already have access to Telstra and Optus cable, which is easily capable of 100mbit/s connections. Why is the Government building a network that we already have. It is outrageous to think that we are building an infrastructure that is going to be out of date within 5 years, and ALREADY exists. Why bother waiting for NBN in your area now? Just jump on an Optus or Telstra cable plan and enjoy the NBN speeds that you’ll be stuck with until the government realises they need to roll out Fibre in 10 years time to keep up with the growing demands of internet and technology.

 

Mid-trials Bike Ride

by nickw | Posted in Blog, Photos

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