Raspberry Pi Availability and Alternatives
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Raspberry Pi Availability
Raspberry Pi is a family of single-board computers first introduced in 2012. Seneca has been invovled with the Raspberry Pi project in various ways since before it was commercially available.
The Covid-19 pandemic has significantly disrupted supply chains throughout the electronics industry, and coupled with increased demand, this means that the Raspberry Pi products are in short supply across the globe.
This page provides some information about Raspberry Pi products, their availability, and alternative boards.
Current and Past Raspberry Pi Boards
There are actually quite a few different "Raspberry Pi" boards -- there are at least 23 main board versions, plus and different configurations, sub-variants, minor board revisions, and special editions.
These are the main boards, capable of running a full operating system (such as Linux), that are available from suppliers:
Raspberry Pi 4
The Raspberry Pi 4 (model B) is a 64-bit, quad-core system with these interfaces:
- WiFi
- Bluetooth
- Full-speed gigabit ethernet
- USB 2.0 and 3.0
- Dual micro-HDMI
- DSI (display serial interface)
- CSI (camera serial interface)
- GPIO connector
The cores are Arm Cortex-A72, and the board is available with 1/2/4/8 GB of RAM.
Raspberry Pi 400
This is a Raspberry Pi 4 built into a small keyboard. It is available as a full desktop kit with peripherals, or just the Pi 400 unit (including keyboard, but without the power supply, SD card, and mouse).
It can be cheaper to buy a Pi 4000 desktop kit than to buy a Pi 4 plus the peripherals. The GPIO connector is exposed on the back of the unit, so most projects interfaced to that connector will work but it is not possible to attach most HAT (Hardware Attached on Top) boards without an adapter cable.
Raspberry Pi 3
The Raspberry Pi 3 Model B+ is a 64/32-bit, quad-core system with these interfaces:
- WiFi
- Bluetooth
- Gigabit ethernet connected via USB 2.0 - max throughput 200-300 Mbps
- USB 2.0
- HDMI
- DSI (display serial interface)
- CSI (camera serial interface)
- GPIO connector
The cores are Arm Cortex-A53 and therefore slower than those in the Pi 4. However, this also means that the board draws less power, and is therefore bettery suited to projects that are powered by alternate energy supplies, such as solar power or battery power. The board has 1 GB of RAM.
Raspberry Pi Zero (Multiple Versions)
The Raspberry Pi Zero is a smaller board, well-suited to compact projects. There are three main variants of this board which may be available from suppliers:
- Pi Zero - this board has a single-core 32-bit processor, 512 MB RAM, no network connectivity, a single mini-USB OTG port, and mini HDMI.
- Pi Zero W - this board has a single-core 32-bit processor, 512 MB RAM, WiFi and Bluetooth capability, a single mini-USB OTG port, and mini HDMI.
- Pi Zero 2 W - this board has a quad-core 64/32-bit processor (same as the Pi 3 B+), 512 MB of RAM, WiFi and Bluetooth capability, a single micro-USB OTG port, and mini HDMI.
All of these boards have a CSI (camera serial interface) connector and the GPIO connector, plus an additional micro-USB connector for power only.
Since the USB ports on these boards are OTG (On-The-Go) ports, they can act in either of two modes:
- As a USB host, connected to a peripheral such as a keyboard or a printer. Multiple devices can be connected through a USB hub. Note that if you're using multiple (or high-powered) peripherals powered through the USB connection, such as a keyboard, flash drive, or mouse, you will probably need to use a powered USB hub.
- As a USB peripheral, connected to a host such as a laptop or PC. In this mode, the Raspberry Pi will use a "gadget driver" to provide some functionality to the host - such as acting like a keyboard, mass storage device, serial port, or printer. Only one host can be connected to the Pi in this mode, and no USB peripherals are available -- so if you want to attach a keyboard, mouse, speakers, or other peripherals, you'll need to use some other method of attachment, such as Bluetooth.
Basic Peripherals and Accessories
The Pi boards all require:
Storage
Storage is usually provided through a micro-SD card. Choose a quality card of at least 16 GB with at least Class 10 and/or UHS-1 speed. Note that there are a lot of counterfit cards in the marketplace (usually with far less capacity than advertised), but sometimes inexpensive cards work well (such as 16GB cards from Dollarama).
The Pi 4, Pi 400, and Pi 3 can boot from a USB device such as an external hard disk drive, or from a network storage device, but doing so requires a significant amount of additional setup.
Display
A display is not required, but can be useful.
The most common type of display is an HDMI monitor. Be sure that you have the correct type of cable:
- Regular HDMI for a Pi 3
- Mini-HDMI for a Pi Zero
- Micro-HDMI for a Pi 4 or Pi 400
- Note that the Pi 4 and Pi 400 can each drive up to two displays, at up to 4K resolution
If you do not have a free HDMI monitor, but want to observe the HDMI output, you can use a HDMI-USB capture device (which can be bought for under $20) and use your laptop, tablet, smartphone, or PC to view the HDMI output from the Pi.
You can also use an LCD display connected to the DSI connector, such as the official Raspberry Pi touchscreen display.
There are many other display options, such as E-ink displays, OLED panels, and small LCDs, but most of these are incapable of displaying the standard desktop, and are instead useful for specialized project indicators, such as showing wifi status, weather information, or other data.
Note that it is possible to program, observe, and manage a Raspberry Pi board entirely over the network connection using the SSH protocol instead of connecting a monitor. SSH is typically used for a command-line interface, but is also capable of supporting graphical user interfaces, file transfer, and more.
Keyboard and Mouse
Any standard USB keyboard or mouse (or trackpad) can be used with the Raspberry Pi boards. Most Bluetooth keyboards and mice can also be used, but you might need to use a USB keyboard/mouse to pair the bluetooth device!
If you are using only an SSH connection, you will not need a keyboard or mouse.
Raspberry Pi Suppliers
Raspberry Pi boards are supplied globally by two production partners: