Media Centre Odyssey Part 2: The Hardware

If you’ve arrived in the middle and want to read the whole story, you can start at the beginning.

The core of my media centre is the Raspberry Pi that stores and supplies the music files. Although the Pi is cheap, it comes utterly bare. You can think of it like buying a motherboard, memory, procesor and graphics card: it is the core of what you need, but is quite a way from being a full computer.

Alongside the Pi, I also need:

  1. A Power supply. To start with, I used the power supply from my HTC Desire but later used a powered USB hub – see below.
  2. An SD card for the operating system. I have one 4GB and one 8GB and the 4GB is a bit on the pokey side. I recommend 8GB.
  3. A hard drive for the music. I started with one with an external power supply, but I really wanted the Pi to run on a single power socket. There are plenty of cheap-ish USB drives now that are powered from USB only, although you will need a powered USB hub. I have a 750GB drive.
  4. A wifi dongle. I tried a few that might have worked in theory but after several evenings fruitless module bashing were not working. I ended up with a “Mini Nano 802.11n” (very generic name) which was cheap and worked out of the box. It reports itself (lsusb) as “Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter”. They can also be powered by a Raspberry Pi without a powered hub, which will be useful for satellite players.
  5. Depending on what came with your other peripherals, you will also probably need a fistful of cables of all shapes and sizes (HDMI, USB, audio…)

Also useful:

  1. A screen, for the first time you boot the Pi to get ssh setup. Possibly, you can get a Raspbian image that will just boot with ssh switched on so you can go headless from the get-go.
  2. A keyboard. I bought a weird floppy thing (and a keyboard, snigger) which is really horrible to type with but folds up small for storage (so does the keyboard, snigger again. OK, enough sniggering).
  3. A case for the Pi, if I don’t want the bare board sitting around. I bought one of these snazzy plastic things. Ths is nice, but if you have a USB hub and a hard drive, you still have a really messy pile of components so the case on the Pi itself doesn’t really help much.

As well as all the core stuff, you also need a USB hub. The Pi has 2 USB ports, which is enough for Wifi and a USB hard drive, but it can only power very low-power peripherals, so as soon as you ask it to run a few USB devices you need a powered USB hub. Luckily, you can also power the Pi itself from the USB hub. The Pi is a sensitive beast, and with the wrong power supply or an unreliable connection, it will crash often especially if you wiggle the cables by moving the Pi while it’s on.

The hub is the thing I had the most problems getting right. I started by buying an anonymous piece of crap on eBay and the Pi crashed all the time. Then I bought a recommended device, which worked for a while until I couldn’t find the power supply for it, plugged in the wrong one. Then there was a nasty smell and instead of a USB hub I had a smouldering little plastic brick. I bought another one, but even then either the Pi or the hard drive plugged into it kept giving up. Also, the later stages of my project used more and more USB ports and it didn’t have enough. Finally, and I don’t want to get precious about this, but it felt really cheap and nasty. So I bought a bigger one on eBay. This thing has more ports, is cheaper and even feels nicer than the one on ModMyPi, so I recommend it.

This is where you see that the Raspberry Pi project can become a bit of a non stop buy-a-thon. I’ve already spent more just on USB hubs than I have on the Pi itself. On the other hand, all the bits and pieces are fairly cheap on their own and if you move slowly and you’re happy to piss away £10 a month on a tinkering project I guess you can probably justify it. At least I’m not pimping my car or anything.

If I cost up the stuff I really needed for this part of the project it looks roughly like this, including postage:

  • Pi: £35
  • SD Card: £8
  • Hard Drive: I blagged one from somewhere else, but you can get one for about £50
  • USB hub: £5
  • mini-USB power cable: £2
  • Wifi dongle: £5

So that’s £105. If I add the keyboard, case and extra cables it’s maybe another £20-25. If I add all the stupid other crap I bought and it didn’t work, about another £40. So more expensive than buying an AppleTV, then. Sigh. But more “fun”! Sigh again.

Anyway, wiring up all this lot, what you get is a bit of a mess, but it does work:

Pi Media Centre: v1Pi Media Centre: v1

So from top to bottom, there is a single plug; the USB hub, the USB-powered hard drive and the Pi itself in a snazzy case. You can see the Pi is plugged into the hub twice, once to provide the Pi with power and the second time to connect the Pi to the other devices plugged into the hub. You might also be able to see the tiny wifi adapter, plugged into the bottom left slot on the hub. These things are very small, which is both good and bad, I guess. I once lost one when it was stuck in one of the holes on the case.

This is a bit of a mess, but with the current architecture I only need wifi and power so I can site this anywhere it can reach a socket. It can be in the bottom of a draw and I never have to look at it. Unfortunately, as I will explain in the next installment, that architecture needs to be modified so that I need way more devices, way more wires and to site it somewhere specific.

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