Pi Day Buyer's Guide

Today is the most delicious holiday of the year: Pi Day! To celebrate everyone's favorite single-board computer, we put together a list of fun and useful products to sweeten your Raspberry Pi experience.

A Raspberry Pi

You'll need a Raspberry Pi to take advantage of everything else listed here, so why not buy one of the latest models? The Raspberry Pi 4 Model B is the current flagship of the lineup, while the Raspberry Pi Zero 2 W is a compact alternative that is perfect for use in tight spaces.

Cameras

Raspberry Pi is a perfect platform for computer vision and machine learning on a budget. You just need to add a camera to get started.

One good option is the official Raspberry Pi High Quality Camera which has a 12.3 megapixel Sony IMX477 image sensor and interchangeable lenses. If you don't need that resolution or want USB connectivity, DFRobot has an 8 megapixel camera with a Sony IMX179 image sensor.

Displays

Your Raspberry Pi has built-in HDMI video output and can accept touchscreen input through USB or GPIO, or both through a DSI ribbon cable. The addition of a display will turn your headless single-board computer into an interactive device.

To go with a tried-and-true format, take a look at DFRobot's classic 5" TFT capacitive touchscreen with a resolution of 800x480. It uses a DSI ribbon cable for simple and clean wiring. It also won't break the bank.

If you want to save power and get clean, crisp text even in bright light, then an e-ink display is for you. This model from Waveshare overs a full 6" of real estate, ultra-fast full refresh times of less than a second, 1448 x 1072 resolution, and a handy HAT interface for your Raspberry Pi.

Maybe your project calls for something special or you want to stand out from the crowd. If so, take a look at Pimoroni's unique HyperPixel 2.1 Round display. As the name suggests, this slick little screen is circular. If it were square, it would have a resolution of 480 x 480. But you have to subtract the corners from that. It also has a capacitive touchscreen overlay.

Sensors

The Raspberry Pi's low cost and small form factor make it ideal for embedded applications, where it can replace traditional microcontrollers and handle computing on the edge. Your imagination is the only limit here, but you may want to consider some of these sensors for your next project.

Avnet's own Renesas Air Quality HATs are great for sensing gases and particulates in the air. The Renesas ZMOD4410 Indoor Air Quality HAT is factory-calibrated and can measure concentrations of Total Volatile Organic Compounds (TVOC). It can also measure humidity and temperature. Monica Houston wrote a great tutorial for this HAT. For outdoor applications, you'll want the Renesas ZMOD4510 outdoor Air Quality HAT.

The botanists among you will love Pimoroni's Grow sensor HAT kit. The HAT provides an interface, including a color screen, which lets you monitor the moisture of your plants through three sensors that you stake into the soil. There are even packages available that come with everything you need to grow some plants—either herbs or chili peppers.

Adafruit's Capacitive Touch HAT lets you turn anything into a sensor for your Raspberry Pi. It gives you 12 inputs, which you can use to connect alligator clip cables to anything conductive. Once you do, you Raspberry Pi will be able to detect whenever you touch one of those objects. Make musical fruit!

Communications

While the modern Raspberry Pi boards come with built-in adapters for communication, such as through WiFi or Bluetooth, you may want to expand that capability. These products will enable communication between your Raspberry Pi and many other devices via a variety of protocols.

Seeed Studios' 2-Channel CAN-BUS(FD) HAT will let you join the world of car hacking. It gives you the ability to tap into a modern car's communications network, so you can intercept or inject messages. By doing so, you can listen for events (like a window rolling down) or send commands (such as to turn on the radio).

If long distance communication is more your speed, Adafruit's LoRa Radio Bonnet will connect you to license-free ISM bands. You can use these frequencies to send data over kilometers of distance. This Bonnet comes with a built-in 128 x 32 pixel OLED screen and three buttons to help you control your device.

Robotics

A Raspberry Pi certainly has the power to act as the brain of a robot and can take advantage of the popular Robot Operating System. But while it is possible to drive small servo motors directly from the GPIO pins, you'll want dedicated drivers for most robots.

The SparkFun Servo pHAT gives you the ability to control up to 16 servo motors via standard 3-pin cables. Here is a similar board from Adafruit that is stackable in case you need to drive more than 16 servos.

Moving from servos to stepper motors will give you full rotation and often more torque. H-bridge drivers are the name of the game here and they can also drive regular DC motors. Adafruit's DC & Stepper Motor HAT will let you control either two stepper motors or four bi-directional DC motors.

Cases

All of the products listed above will extend the capabilities of your Raspberry Pi, but sometimes you just want to use it as is. In that situation, you'll want a case to protect your Raspberry Pi.

As the basic end of the spectrum is this simple case for the Raspberry Pi 4 Model B. It's a no-frills solution, but very affordable. If you want something more stylish and substantial that gives you cooling and an SSD bay, the sleek aluminum Argon ONE M.2 case is for you.

The gamers out there will love the retro styling of the NESPi 4 case, which scratches that nostalgia itch. If you want to build your own NAS or Raspberry Pi cluster, the Rack Tower Pro gives you eight layers of bays for your Raspberry Pis or hard drives.