Choosing a Raspberry Pi
In This Chapter
- Raspberry Pi models available
- Differences among the models
- Choosing your model
- Buying your Raspberry Pi
As of this writing, four versions of the Raspberry Pi are available—the Model A+, the Model B, the Model B+, and the Model 2. Each is slightly different from the others, and each has its pros and cons, depending on your intended use.
For most DIY projects, it’s usually best to get the newest model so you have the most up-to-date equipment and software, but the older models still have their charm and usefulness.
Which is right for you depends on what you want to use your Raspberry Pi for. If you’re interested in multimedia projects, the B+ is your model. If you’d prefer to just run a small, out-of-the-way automation system, the Model A+ will do the trick. Whichever model you choose, you can do plenty of projects with it.
In this chapter, we take an in-depth look at the four models, the hardware of each, and ways to pick the right one for your needs.
Let’s start by looking at some of the very basic details about each model. It might surprise you that the actual chip and processor are quite similar on each model. The latest model has gained some processing power, with more memory and USB ports added as new models launched.
Model A+
Model B+
Model B
Model 2
All the Raspberry Pi models look mostly the same but have a few upgrades.
The following table offers a breakdown of the key points of each model.
DEFINITION
Random access memory (RAM) is a form of computer storage from which programs can temporarily read and write data. Nearly every computer has RAM these days, including your smartphone. Synchronous dynamic random access memory (SDRAM) is RAM that can run at higher clock speeds than other types of RAM. The speed is synchronized with the system speed. GPIO, or general-purpose input/output, is a connector that enables you to connect your Raspberry Pi to other computers for more advanced projects.
Each iteration of the Raspberry Pi is an improvement on the previous version. The Model B got an upgrade in RAM from the Model A to increase its speed, while the B+ was an overhaul of the whole thing, with additional USB ports, a different type of SD card, and more. The B+ has a totally different setup and is much larger than the other models. The Model 2 keeps the design of the B+ while swapping out the processor and RAM. Still, each is about the size of a credit card and only weighs a few ounces. And regardless of which model you get, you’ll be able to complete every project in this book. You’ll definitely notice some speed improvements with video- and graphic-intensive programs with the B and B+ though.
Let’s start by taking a look at its hardware.
Unlike its older brothers, the Raspberry Pi Model A+ only has one USB port, no Ethernet port, and only 256MB RAM. It consumes about a third of the power the Model B does, so it’s great for low-power projects.
The Model A+ Raspberry Pi.
Model A+ Hardware Specifications
The Raspberry Pi Model A+ is designed specifically to run small, portable equipment that doesn’t need internet access. Because of that, it’s even more stripped down than the B, B+, and 2 models. It’s also physically smaller than the other two, coming in at about an inch less in length. Here’s an overview of what’s on the board:
256MB RAM: The small amount of RAM means this model isn’t as powerful as the others, but it also means it consumes less power.
Broadcom BCM2835 SoC with 700MHz low-power ARM1176JZF-S applications process: The processor is the Raspberry Pi’s main brain, and it’s the same for all three of the bottom-tier models. It was originally designed for mobile phones, but it’s powerful enough for the Raspberry Pi to run full desktop software.
Dual-core VideoCore IV multimedia co-processor: This graphics processor is the same for all four models. It’s integrated into the SoC, but it’s a separate piece of hardware and enables the Raspberry Pi to power all kinds of graphically intense games and applications.
Micro SD slot: This is for the micro SD card. The Raspberry Pi doesn’t have a regular hard drive. Instead, you install the operating systems on an SD card using your home computer. (I cover this process in Chapter 8.)
5-volt micro USB power slot: This is where you plug in your Raspberry Pi for power. (I walk you through getting a power supply that works with the Pi in the next chapter.)
That’s it for the Raspberry Pi’s main hardware. The key differences between the Model A+ and the other models are the ports.
HARDWARE HELPER
The Raspberry Pi only has a handful of USB slots, but you can always add more using a powered USB hub. Nonpowered USB hubs won’t work because the Pi doesn’t have enough power to share. You can find powered USB hubs at almost any electronics retailer.
Model A+ Ports and Connectors
The price, size, and power consumption of the Model A+ are what set it apart from the other models, but it comes at the cost of ports. Here are the ports you get on the Model A+:
Single USB connector: You can only connect one USB device to the Raspberry Pi Model A+ at a time. That means if you want to use both a keyboard and a mouse, you need an external USB hub.
HDMI port: You can output video from the Raspberry Pi Model A+ using the HDMI port, which also outputs audio. The HDMI output gives you a clearer HD picture and works best with modern monitors or televisions.
3.5mm audio jack: This audio-plus-video jack does double-duty. For audio, you need a 3.5mm audio cable, but if you want to send out composite video, you also need a 3.5mm-to-3 RCA adapter cable. The Model A+ also improves on previous versions (Models A, B, and B+) by adding a dedicated low-noise power supply so it can send a better signal.
GPIO (general-purpose input/output) connector: The GPIO connector enables you to hardwire the Raspberry Pi into other components for more advanced DIY projects. (If this sounds a bit scary, don’t worry. I cover this in Chapter 6.) The Model A+ has a 40-pin GPIO header.
Camera connector: This allows you to connect the official Raspberry Pi camera.
Display connector: The display connector is great if you want to hardwire your Raspberry Pi to a screen instead of going through the HDMI port.
HARDWARE HELPER
The Raspberry Pi Model A+ does not have an Ethernet jack, which means you can’t get connected to the internet with it unless you use the one USB connector for a Wi-Fi adapter.
That’s it. As mentioned, the Raspberry Pi Model A+ is the minimalist of the bunch. It still gets the job done, but it’s not the best for beginners looking to play around with a lot of different types of projects.
The Model B
The Raspberry Pi Model B is a step up from the Model A+, but the two have the same basic blueprint. The Model B has a bit more power in the form of more RAM and more ports to work with.
The Model B Raspberry Pi.
Model B Hardware Specifications
With the exception of the on-board RAM, the hardware in the Model B is similar to the Model A+’s:
512MB RAM: The Model B has double the RAM the Model A had (256MB), so it can run a lot more advanced software. It also means it’s a lot better at doing anything with video, including encoding and outputting in HD.
Broadcom BCM2835 SoC with 700MHz low-power ARM1176JZF-S applications process: This processor is the same for all three models.
Dual-core VideoCore IV multimedia co-processor: This graphics processor is the same for all three models.
SD, MMC, SDIO card slot: The Model B is the only currently available model of the Raspberry Pi that uses a standard-size SD card slot.
5-volt micro USB power slot: This is where you plug in your Raspberry Pi for power. All four models have this slot.
HARDWARE HELPER
The upgrade from 256MB RAM in the Model A to 512MB in Model B (and the B+) adds a significant boost to the Raspberry Pi’s multimedia power. 256MB RAM is just enough to run a media server, but 512MB makes the Raspberry Pi much more suited for games and video. The Model 2’s 1GB is even faster, and you can run a lot more complicated programs with it.
The Model B has a few more ports that make it a lot easier to work with.
Model B Ports and Connectors
The Model B has a similar set of ports and connectors to the Model A+, with an additional USB port and Ethernet jack.
Two USB connectors: You can connect two different USB devices to the Raspberry Pi Model B at once, or more if you get a powered USB hub.
10/100 Ethernet RJ45 jack: The Ethernet jack enables you to connect your Pi to the internet via an Ethernet cable.
HDMI port and composite RCA output: These are the same as the Model A+.
3.5mm audio jack: The Model B has a 3.5mm audio jack output.
GPIO (general-purpose input/output) connector: The Model B has a 26-pin GPIO header.
Camera connector: This is the same for all four models.
Display connector: This is the same for all four models.
The Model B manages to get most of what you need onto the board, but although it’s perfectly good for nearly any DIY project, it’s not as powerful as the B+ or the 2.
The Model B+
The Raspberry Pi Model B+ marks the first big advancement in the Raspberry Pi hardware line. Unlike the leap from the original Raspberry Pi to the Model B, the Model B+ changes the overall architecture and adds a ton of improvements.
The Model B+ Raspberry Pi.
Model B+ Hardware Specifications
With the exception of a new micro SD card slot, all the improvements to the B+ come in the form of new ports. So for the most part, the specifications are basically the same as the Model B:
512MB RAM: The Model B+ has the same amount of RAM as the B.
Broadcom BCM2835 SoC with 700 MHz low-power ARM1176JZF-S applications process: This processor is the same for all three of the bottom-tier models.
Dual-core VideoCore IV multimedia co-processor: This graphics processor is the same for all four models.
SDIO card slot: This is for the micro SD card.
5-volt micro USB power slot: This is where you plug in your Raspberry Pi for power. All four models have this slot.
HARDWARE HELPER
The Model B+ is a nice upgrade to the B that really makes it easier to use and a bit more powerful. The audio jack in particular features an upgrade that makes output audio sound a lot better than the older models.
The big difference with the Model B+ is the ports, so let’s take a look at how it changes things up.
Model B+ Ports and Connectors
Like any computer, the Raspberry Pi has a variety of ports and connectors so you can attach accessories, screens, and other cables. The Model B+ differs from the Model B and A+ in that it has more USB connectors. Both the A+ and B+ have more GPIO pins as well.
Four USB connectors: The Model B+ doubles the USB connectors the Model B has for a total of four. This makes it a lot easier to use as a computer with a keyboard, mouse, Wi-Fi adapter, and whatever else you need to plug into it.
10/100 Ethernet RJ45 jack: This is the same as the Model B.
HDMI: The HDMI port is the same as the Model B.
3.5mm audio/video jack: This is the same as the audio/video jack on the Model A+.
GPIO (general-purpose input/output) connector: The B+ (and the Model A+) has a GPIO header with 40 pins.
Camera connector: This is the same for all four models.
Display connector: This is the same for all four models.
The Model 2 improves on the previous models by adding in a new CPU and more RAM.
The Model 2 Raspberry Pi.
Model 2 Hardware Specifications
The Model 2 has a few updates to be happy about:
1GB RAM: The Model 2 has 1GB RAM–twice that of Models B and B+.
Broadcom BCM2836 quad-core 900Mhz ARMv7 processor: The Model 2 gets a brand-new processor that’s about six times faster than the ones on previous models.
Dual-core VideoCore IV multimedia co-processor: This graphics processor is the same for all four models.
SDIO card slot: This is for the micro SD card.
5-volt micro USB power slot: This is where you plug in your Raspberry Pi for power. All four models have this slot.
Other than the speed, the Model 2 is about the same as the B+ with everything else.
The Raspberry Pi has several ports and connectors. The Model 2 is pretty much the same as the Model B+ in this respect.
Four USB connectors: The Model 2 has four USB ports.
10/100 Ethernet RJ45 jack: This is the same as the Model B+.
HDMI: The HDMI port is the same as the Model B+.
3.5mm audio/video jack: This is the same as the audio/video jack on Models A+ and B+.
GPIO (general-purpose input/output) connector: The Model 2 (and Models B+ and A+) has a GPIO header with 40 pins.
Camera connector: This is the same for all four models.
Display connector: This is the same for all four models.
That’s it for technical details. Let’s move on to picking the right Raspberry Pi for your specific needs.
Which Model Is for You?
Each Raspberry Pi model is suitable for different projects. Because of that, it’s a good idea to know what you want to do with your Raspberry Pi before you purchase one.
There’s no real wrong choice here. Among the four models, each can do almost everything the others can, although the newer B, B+, and 2 models are much better suited to multimedia work.
What Do You Want to Do?
Which model is best for you depends on what you want to start making.
The Model A+ is aimed toward more advanced users who want to make low-power DIY projects that don’t require a lot of external components. Because the Model A+ only has one USB, it’s not as well suited for running Linux or doing anything where you need a keyboard and mouse.
In addition, the lack of Ethernet makes it a poor choice for most beginners who’ll need to download and install a lot of new software on their Pi to complete the more popular projects.
However, the Model A+ is great for projects like making a DIY camera because it doesn’t consume much power and you won’t need the USB ports for the camera.
The B, B+, and 2 models are all equally good for just about everything else. If you want to use the Raspberry Pi as a full computer, the B, B+, and 2 models have all the USB ports you’ll need. Because the B, B+, and 2 models have more RAM, they’re also better suited for multimedia projects and games. If you really want to do some work with your Raspberry Pi, the Model 2 is powerful enough to handle all kinds of modern applications and is your best choice.
If you’re not sure which is best for you, the B+ or 2 is the likely the one to go with because it’s the newest model and it’ll have everything you could possibly need.
PI POINTER
Besides the currently available models of the Raspberry Pi, different revisions existed as well. These are no longer available to purchase, but this is how they differed from current models:
Model A: The original Model A was the same size as the Model B, had a standard SD card slot, and cost $25.
Model B Rev 1: The original Model B, known as revision 1, only had 256MB RAM. Otherwise, it was the same as the currently available Model B (known as revision 2).
Pros and Cons of Models B, B+, and 2
For the time being, the B, B+, and 2 models are all still available, but the Model 2 is clearly meant as a replacement for Models B and B+. Because they’re all available, the main pros and cons are really a matter of which accessories you already own.
The big difference between the B and the 2 (and B+) is the SD card slot. The B uses a standard SD card, whereas the Model 2 uses a micro SD. If you already have a Raspberry Pi and have made a lot of SD cards with all your different operating systems, you’ll basically have to start over from scratch to use Models B+ or 2. Likewise, the standard SD card pokes out from the board, whereas the micro SD is flush.
Similarly, if you already purchased or made a case for an earlier model, you’ll have to get a new one. (I talk more about cases in Chapter 4.)
If you’re starting from scratch though, the Model 2 is definitely the way to go. It’s more powerful, has more ports, and is going to be a better system all around.
As of this writing, the Raspberry Pi has a set price structure for the models, and all are generally only available through a few authorized dealers.
The pricing structure for the Raspberry Pi is intentionally set in stone:
Model A+: $25
Model B: $35
Model B+: $35
Model 2: $35
For the most part, these prices shouldn’t fluctuate for any reason, unless, perhaps, a new model is released. If you go through an unauthorized seller, you might end up paying a little more for your Raspberry Pi.
PI POINTER
The prices of the Raspberry Pi are set at $20 and $35, so if anyone’s ever trying to charge you more than that, look elsewhere. They’re widely available, so you shouldn’t have trouble finding an authorized seller and lower price.
Every region has authorized Raspberry Pi sellers, but in the United States, the official seller is element14 (element14.com).
You also can find a Raspberry Pi at a number of resellers, including larger sites like Amazon, but most of them are getting their Raspberry Pis from element14. These other resellers might charge more than the set $25 and $35 price points, too.
The Least You Need to Know
- A few different models of Raspberry Pi exist as of this writing–the Model A+, the Model B, the Model B+, and the Model 2.
- The main difference among the four models is the number of ports they have and their overall power.
- Each model has its strengths and weaknesses, but you’ll be able to do most of the projects in this book on any model.
- Depending on your region, you’ll need to buy your Raspberry Pi from an authorized retailer. But you should be able to pay the same price from any authorized retailer.