Raspberry Pi Setup Notes

Figure 1 | Raspberry Pi
Introduction

First, let me clarify that this blog is about the $35 Model B (512 MB RAM, 2 USB ports, and an Ethernet port), not its cheaper cousin, the $25 Model A (256 MB RAM, 1 USB port, no Ethernet port).

To learn more, see the FAQ. The FAQ is short and informative. I recommend reading it even if you don't have questions.

Take 1

My first goal was to get my Raspberry Pi up and running.

The first thing I needed was power. So, I hooked up a cable/adapter combination to connect the USB A port on my laptop (5 V, 500-900 mA) to the USB Micro B port on my Raspberry Pi. Doing so caused the red LED on my Pi to turn on (see figure 1). So, I figured I had a good power source established. (As it turns out, learning about USB standards is one of the many educational side-effects of trying to setup a Pi device of your own. There are some finer points about whether the power source is providing the Pi with sufficient power, relative to the required 3.3 volts. However, I won't get into that just now.)

My next step was to provide my Pi with something beyond the firmware that it shipped with. I needed to get some software to comprise an operating system (OS). Thankfully, the Pi box points you in the right direction on where to download the OS. As most folks seem to recommend, I downloaded the version of Linux that is called Raspbian "wheezy". (There are some finer points here as well, such as the right way to get the image file onto the SD card that serves as the Pi's primary data source. Again, I won't get into those details here and now.)

If you power your Pi after inserting a correctly imaged SD card, you should not only see the solid red "power" LED but also the flickering of the green "activity" LED as the Pi goes through its boot up process. But without a display you're not going to find out any more than that.

So, it seemed that the SD card was valid, but I still couldn't confirm what was going on as far as the boot process. The quickest way for me to get a display going was to run one of those yellow RCA/composite video cables from the Pi's RCA/composite output to my TV's RCA/composite input. (Everyone either has a RCA/composite cable lying around or can easily pick one up from RadioShack or online.) Once I connected both ends of the RCA/composite video cable and switched my TV to video1 (or video2, depending on which input I had plugged by RCA/composite cable into), I was able to see the familiar Pi configuration menu.

Figure 2 | Raspberry Pi Setup (Take 1)

The setup described above is summarized in figure 2. At this point I figured I had a working Pi and I could start thinking about a more practical setup.

Take 2

In my quest to make my Pi more portable I was helped by several online articles and videos that describe how to hookup a Pi to the now defunct Motorola/AT&T Atrix 4G Laptop Dock. The dock is available for $60 or so online and is a compact way to augment the Pi with audio (the dock has speakers), video, keyboard, mouse (track pad), and power all in one shot. I haven't seen any of the site describe the setup I have documented in figure 3. I will describe in it a bit more detail to try and fill in the blanks and provide additional information.

Figure 3 | Raspberry Pi Setup (Take 2)
As the astute reader will note, the most efficient route is to go directly from the connector type on the Pi to the connector type on the dock. However, you will find that not all imaginable cables, adapters, and dongles (henceforth mostly referred to generically as "connectors") are equally available. Given a random combination from connector type A to connector type B (e.g. HDMI A port/female to Micro HDMI D plug/male shown in figure 3), chances are that such a cable does not exist or isn't readily available. Many that are available are not available in the US and have to be shipped from overseas, mostly from China. I should mention here that someone with adequate knowledge of electronics and access to electronics components (e.g. some adapters may require a resistor to be added to reduce the current) and equipment (soldering iron etc.) can create the desired cable at home. For those who are interested in taking that extra step toward electronics, the best book I've seen on the subject is Make: Electronics by Charles Platt (O'Reilly, 2009).

As you will note by studying the setup described in figure 3, at least one connector in any leg of the setup must be a cable (in order to provide the needed maneuverability). The remaining connectors in a leg can be adapters/dongles. For example, the HDMI leg of the setup has two connectors, i.e. #1 and #2. Only one of them needs to be a cable. The other is free to be a cable or an adapter/dongle. The same goes for the middle leg. However, the last (power) leg has only one connector, i.e. #5. Therefore, #5 must be a cable.

For your convenience, I am listing out the connectors used in figure 3. Again, make sure that at least one connector in each leg is a cable. See figure 4 for a useful diagram of the standard USB types.
  • #1. HDMI A (regular) male/plug to HDMI D (micro) male/plug cable or adapter/dongle.
  • #2. HDMI D (micro) female/receptor/port to HDMI D (micro) female/receptor/port cable or adapter/dongle. Also known as a gender changer (this is the case whenever both ends of a connector have exactly the same connection type).
  • #3. USB A (regular) male/plug to USB A (regular) male/plug cable or adapter/dongle (gender changer). 
  • #4. USB A (regular) female/receptor/port to USB B (micro) female/receptor/port cable or adapter/dongle.
  • #5. USB B (micro) male/plug splitter (a micro female/receptor/port at one end and two micro male/plugs at the other end).
Figure 4 | USB Types
A final point about terminology. As you would have noted in the text above, the male connector is variously also known as a jack or a plug. Similarly, the female receptacle is also known as a socket. As a point of confusion, in the US, a jack can often refer to a female receptacle. Furthermore, in the US, a jack can refer simply to the immobile part of the connection pair that's typically attached to a wall or panel.and a plug can refer to the mobile part of the connector pair that's typically attached to a wire. For more on this interesting topic, see the following article. Due to the above mentioned sources for potential confusion, I recommend always using the terms male connector and female connector so that there is no room for ambiguity or interpretation. This is the approach I have consistently tried to use in this blog post.

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