Raspberry Pi – $25 computer with a huge amount of potential

Raspberry Pi – $25 computer with a huge amount of potential

I’ve just stumbled across the Raspberry Pi (RasPi) and have spent the past 3 hours contently reading about it and the Gertboard. In a nutshell, RasPi is a credit card sized computer with USB, HDMI, composite and analogue audio I/O ports – all powered by a 600MHz Broadcom ARM processor and 128MB RAM – selling for $25. There’s a $35 “B” model which, as I understand it, has 256MB RAM and an Ethernet port. An SD card reader provides permanent storage for the device.

The RasPi beta boards have been shown to successfully run Linux and are set to be the core of a host of home-brew devices performing a variety of tasks. The boards can compile and run high level programming languages and would be perfect to teach programming to school kids and individuals alike.

However, the thing that interested me most was Gertboard. This is a programmable expansion board for the RasPi. It was created by Broadcom Engineer Gert van Loo and has been designed to teach both electronics and low level programming. In another nutshell, it allows the programming and control of motors, relays, LEDs, etc. I have personally dabbled with electronics (with little success) and this is something that really interests me. I half wish I did electronics as a degree rather than spending 3 years learning very little of real value on a Computer Science course. I dabbled with low level programming in the form of Intel 8086 compatible assembly language whilst at University and I quite enjoyed this also.

I rarely jump on anything shiny and new, eagerly anticipating its release; however the RasPi and Gertboard have gotten my attention and I will be sure to pick some up when they’re released.

Did you not go to school..? The correct use of the apostrophe

Did you not go to school..? The correct use of the apostrophe

It’s really not a difficult bit of punctuation, however I see so many painfully inventive uses/omissions of it. The one that inspired this blog post was on a food menu. A Ploughman's lunch is a common English lunch consisting of bread, cheese, cold meats, etc. Apparently you can get different types of Plougman’s lunches, which the pub had put under the menu category Plougmen’.

I’m not  actually sure whether the plural of Plougman’s is Ploughmen, let alone Plougmen’. If anything, it’s probably Plougman’s lunches or maybe Plougmen’s lunches. Who knows.

Anyway, it’s really fucking simple. There’s 2 common uses of the apostrophe:

Signifying missing characters in a word

If you are missing out characters in a word, use a ‘ in place of them. For example, you’re instead of you are. The ‘ replaces the space and the a. It’s instead of it is. The ‘ replaces the space and the i. “Learn the fuckin’ grammar” instead of “Learn the fucking grammar”. The ‘ replaces the g.

Simple.

Signifying ownership

If someone owns something, use a ‘ to signify this.

If the word which is the owner of the object is not already plural, add ‘s to the end of the owner. For example, if Bob owned a hat, you would add ‘s to Bob making Bob’s hat. If the girl owned a dog, you would add ‘s to the girl, making the girl’s dog.

If the word is already plural, add ‘ to the end. For example, if the girls owned a hat you would add ‘ to the girls making the girls’ hat. If the dogs owned a badger, you would add ‘ to the dogs making the dogs’ badger. If the boys owned some elephants, you would add ‘ to the end of the boys making the boys’ elephants. As you can see, whether or not the object or plural is irrelevant to the use of the apostrophe on the owner.

Keep in mind that an s on the end of the owner does not always mean it’s plural. For example, Chris, referring to a guy called Chris. If Chris owned a hamster, because Chris is singular, you would still add ‘s to make Chris’s hamster.

Simple.

 

Now, go forth into the world and stop misusing or omitting this important piece of punctuation.

Creating a wireless network with multiple access points

Following on from my earlier article on converting an old wireless router into an access point you can have many wireless access points dotted around your house in order to provide the best wireless coverage without the need for expensive repeaters. To do this, you will need to do the following:

  1. Give each access point a different management IP address
  2. Give each access point a different channel – the further apart the channels the better
  3. Give each access point the same SSID
  4. Give each access point the same encryption type and key

It’s as simple as that. If one access point disappears (e.g. is unplugged) wireless devices should relatively seamlessly start using another one. As you move around the house, wireless devices should seamlessly switch between access points as they engage in client controller handover to ensure they achieve the best signal.

Converting an old wireless router into an access point

Converting an old wireless router into an access point

A “wireless router” is actually quite a complex device. It comprises of a router, a network switch and a Wireless Access Point. A router is a bridge between two networks – typically the Internet and a Local Area Network. A switch (in its simplest form) connects many devices on the same network – typically a Local Area Network. A Wireless Access Point (WAP) provides a point of connectivity for wireless devices onto a network – typically a Local Area Network. A WAP can be thought of a little bit like a wireless switch in such that it connects many wireless devices on the same network.

I have a tonne of wireless routers knocking around. Most of these are Netgear WGR614 (v9) routers which I acquired whilst I was a student, forced to suffer the pain of being a Virgin Media customer. There’s 2 ways to use a wireless router as an access point. The right way and the easy way. I shall cover each of these below.

Edit: For both methods you will likely want to disable DHCP on the router via its web control panel – Thanks to @Duffy177 for pointing this out.

The Easy Way

A typical wireless router is constructed in such that the routing happens between its “WAN” port and its switch. As such, if you just plug all of your devices into the switch ports and don’t use the “WAN” port, you have a switch and wireless access point rolled into one. It’s normally pretty easy to identify which is the “WAN” port and which are the switch ports as most routers group the ports together and some even colour the WAN port differently. The below image of the Netgear WGR614 shows this:

Netgear WGR614 (v9)

 

 

 

 

 

 

 

 

The Right Way

The right way is sadly not always possible as it depends if the router supports it. When you log into the web interface, look for a setting relating to using the router as an access point or assigning the WAN port to the switch. If you can enable this option, you can use all of the ports on the router as it has now stopped routing. The below image of the DD-WRT firmware config shows an example of this:

DD-WRT Assign WAN Port to Switch

 

 

 

 

That’s about it. Hopefully you can recycle some old routers and give them a new lease of life.

 

I hate public transport

I hate public transport

I went to Birmingham today. Exciting, eh? Well, I took the train! The train is a marvelous invention and the pinnacle of British Engineering. However… I should have taken the fucking car. This is why:

  1. My car is never late – it’s always where I expect it to be at the time I expect it to be there. The train never fails to be late.
  2. It takes 35 mins to drive from here to Birmingham… the train takes 45.
  3. It costs about £11 in fuel to drive to Birmingham from here. The train cost £14.
  4. It is generally assumed that I can use my car at any time. An ‘any time day return’ train ticket apparently means ‘any time as long as it’s a Virgin train’. Where the fuck was the warning of that..?
  5. There’s always enough seats for everyone in my car – the police get pissy if there’s not. The train has seats for only 1/2 the passengers.
  6. My car carries no cocky teenagers who think they own the place. Those found on the train are rather set to own criminal records and children by the age of 15.

To summarize… fuck the environment. Next time, I’m driving.