What Pi to use: the Raspberry Pi Comparison

Raspberry Pi models are great, but there are several to choose from. So, which one should you choose for your next Raspberry Pi project?

Your Pi Flavours

• Raspberry Pi A +
• Raspberry Pi 2 Model B
• Raspberry Pi Model B +
• Raspberry Pi 3
• Raspberry Pi 3 Model B+
• Raspberry Pi 4 Model B
• Raspberry Pi Zero
• Raspberry Pi Zero W
• Compute Module
• Compute Module 3
• Compute Module 3 Lite

THE raspberry Pi, Does it exist?

People talk about the raspberry pi all the time these days, when they talk about the RPi  they usually have this idea of a small credit card computer that has various I/O ports and can replace a PC for most typical applications, including document writing, surfing the web, and writing programs. BUT is there a single computer that can be called THE raspberry Pi?
The short answer is kind off, so lets hear about these Raspberry Pi mini computers shall we?

So, since you are reading this you have decided that you are going to design and or build a Raspberry Pi Project, but you can’t find the Pi that fits you. We’ll help you out in that department.

What are your requirements?

When you are in the process of making a decision, you usually write down your requirements; computers are no exception! So the first task you have is to determine what is the most important one for your project, get your requirements on ‘paper’. Here is a list that will help you narrow down.

• Speed: Processing power of the system
• Memory: How much RAM and ROM or HD space the system has
• Size and weight: The physical size and weight of the computing system
• Cost: The financial cost of the system
• I/O: How much I/O support is available

Speed

Speed might be your most important factor in a computing scenario. The faster your computer is, the more work it can do before slowing down your system. The raspberry pi computers are very fast compared to microcontrollers such as PIC, STM, AVR, but there is a difference between the Pi Computer and your microcontroller.

Microcontrollers come in many flavours (8, 16, 32 bit are most common these days), just as with the pi. The first Raspberry Pi computer, the model B, features a quad-core 32-bit ARM Cortex processor, whereas the cheaper version, which was released shortly after the B, the model A, has a single-core 700MHz ARM processor. This means the Raspberry Pi B can do four things simultaneously across its separate cores, but tasks on a single core on the model B will be approximately 30 percent faster than on the A (that, however, is one big assumption for many reasons). The later models, such as the Raspberry Pi 3 B, have a 1.2Ghz 64-bit quad-core processor, which is not only faster than the Raspberry Pi 2, but it can handle larger data sizes. Other Pi computers, such as the Compute range, have similar core speeds, ranging from 700MHz to 1.2GHz.

Memory

Memory, or RAM, can be one of the critical point in your computing project. Operating systems are notorious for using large amount of RAM, just take a look at your windows: 4gb for just running windows… So, if you are going to use an OS (and for most of us an OS is a must on the pi) , maximizing RAM would not be a bad move. The Raspberry Pi A computer has between 256MB and 512MB of RAM, whereas the Raspberry 2 and 3B have 1GB; however, this is shared with the GPU. The newer Raspberry Pi 4B series go from 2GB to whacking 8GB.

Size and Weight

Because the Raspberry pi Computers are already very small (like the pi Zero) this might not be an important factor for you. For most users, this requirement may not apply. However, some projects may have strict requirements, in which case the Raspberry Pi Compute may come out on top. However, the Compute modules come in DDR like packages, which means they need a host PCB to fit into so they can be connected to I/O devices, as well as power. This may end up being larger and heavier than just using a Raspberry Pi A or B. The Raspberry Pi Zero is the smallest Pi computer available that also contains I/O, including USB, HDMI, and an SD card slot. However, the Zero has lower RAM and processing capabilities than the Raspberry 3 B.

I/O

If you are going to use your computer for office tasks then a laptop or computer would be a better choice. Raspberry Pi computers are used usually because there is a need for I/O.
The raspberry pi A and B (+) versions are great for connecting to external circuits and devices since they have a pin header. The A version has a whopping 8 GPIO ports, while the B model has 17 of them. Now if you really need more you can always use expansion chips. But if you don’t mind using the Compute model then you have 46 GPIO’s at your disposal, great for industrial applications.

Networking

Comparing GPIO, memory, and CPU processing power is all fine and good, but arguably the most important difference between the different Raspberry Pi computers is their network capabilities. The first models, the A and A+, lack any networking capabilities at all, whereas the model 1 B and up have an Ethernet port. But not every location has Ethernet access, which is where the model 3 B comes in with an integrated wireless network adaptor, no more need fora n USB Wi-Fi stick. The Compute module and Zero models do not come with internet capabilities, with the exception of the Zero Wireless, which also has an integrated Wi-Fi module.

Side note: “Users of the model 3 B who wanted to pass CE and FCC conformity had some issues due to the integrated Wi-Fi IC, which is why the Raspberry Pi foundation developed the more recent model 3 B+, which houses the Wi-Fi circuitry in a metal shield and is designed to meet CE and FCC requirements.”

Models

Well hellow, what is the “+” in my model name? This inclusion usually indicates improvements in the design without releasing a new product. For example, the Raspberry Pi model A has 256MB RAM, whereas the Raspberry Pi model A+ has 512MB RAM, a microSD slot, and more GPIO. The Raspberry Pi 2 Model B has two USB ports and two mounting holes, whereas the Model B + has four USB ports, four mounting ports, a faster CPU, increased GPIO, and less power consumption.

So, Which One?

So after exploring these requirements, which Pi should you pick, where do we start?
Well here is a list of the current raspberry pi’s available:

Raspberry Pi Model A: Use this model for a low-cost project that needs a complete computer with no networking capabilities and decent I/O support

Raspberry Pi Model B: This model can be used for a project where price is no object and the most powerful Pi is needed. This model also contains easy-to-use I/O, so it is suitable for first Pi projects.

Raspberry Pi Compute: This model is best for industrial applications where many I/O lines are needed. This model also maintains strong CPU capabilities.

Raspberry Pi Zero: This model is best for an ultra low-cost, tiny-space-constrained project that requires a fully functioning computer and would benefit from wireless connectivity.

* There are 4 versions of the Pi 4B, the 1GB version is no longer available, but the 2GB version has been made the same price as the Pi 3B+

* Compute Modules are created for placement into production ready designs. They do not include standard connectors.
* Compute Module 3 Lite brings the SD card interface to the Module pins so a user can wire this up to an eMMC or SD card.

Conclusion:

Looking at today’s prices for the Pi’s I wouldn’t bother going for the older version for the full format B version, the Pi4B 2GB is (almost) the same price as en 2B is and gives you much more for your money.

Other then that it’s up to you to decide what Pi version suits you best.