A tiny-but-mighty open-source carrier board for the Raspberry Pi CM4
Piunora is a compact, easy-to-use development board for electronics prototyping with Linux. It has a familiar form factor, legible pin labels, and a design that’s well suited to space-constrained applications.
As a carrier board for the Raspberry Pi Compute Module 4 (CM4), Piunora is essentially a tiny version of the Raspberry Pi 4 Single Board Computer (SBC) with added flexibility to accommodate custom form factors. CM4-based devices like Piunora are fully compatible with software that was written for the Raspberry Pi 4, as long as that software accounts for the hardware peripherals in use. There are also versions of the CM4 that include eMMC memory, which is more reliable than a traditional SD card.
It may be small, but Piunora is packed with powerful peripherals that will come in handy for rapid prototyping and embedded machine-learning applications. Examples include an HDM1 port, camera-input connectors, and PCI-e support, which is not present on a standard Raspberry Pi 4. Finally, the M.2 B-Key port on the rear of the board is not only useful for SSD storage, it can also host a diverse range of PCI-e expansion boards.
Great for Working with Electronics
A Qwiic/Stemma-QT-compatible connector makes it quick and easy to use I²C sensors—from Adafruit, SparkFun, and others—via Python. That puts hundreds of high-end sensors and peripherals at your fingertips, with no soldering or breadboarding required, which makes developing powerful, sensor-based machine-learning applications a breeze.
Qwiic and Stemma QT put the rapid back in rapid prototyping by allowing you to connect and daisy-chain I²C devices. Using just one connector, you can add multiple devices to Piunora. The Qwiic connector was developed by SparkFun (Qwiic) and then picked up by Adafruit (Stemma QT). Both companies offer a number of affordable sensors, displays, and input devices. All of their boards have easy-to-use Python drivers that work with the Raspberry Pi and the CM4.
The demo above uses Adafruit Blinka—a library that enables CircuitPython code in Linux—and an Adafruit VCNL4040 distance sensor attached by a single cable to Piunora’s Qwiic/Stemma-QT connector.
Unlike any of the official Raspberry Pi boards, Piunora includes an on-board ADC that provides true-analog inputs. Six ADC channels are exposed to pin headers and two additional channels are broken out to solder pads on the bottom of the board for when you need that little bit of extra analog.
To make prototyping easier, Piunora also includes two user buttons and an RGB LED for simple status feedback in your applications. We provide sample code that allows you to shutdown Piunora safely using the button on the back.
A New Way to Develop With Raspberry Pi
Piunora includes a USB Type-C port that’s wired for both power and USB 2.0 data. Because it draws less power than a full-featured Raspberry Pi 4, it will happily interface with any modern USB port rated for 900 mA or higher (most USB Type-A 3.0+ and USB Type-C ports). As a result, you can use Piunora simply by plugging it into your computer and connecting to it via USB gadget mode, either as a virtual Ethernet interface, a USB Serial connection, or a USB mass-storage device.
Thanks to Adafruit Blinka (a compatibility layer for CircuitPython on Linux SBCs), you can use Piunora just like any other CircuitPython dev board, which allows you to take advantage of the huge collection of existing drivers for that ecosystem. Our goal is to make it as easy as possible to develop embedded applications with Piunora, and we are actively developing open-source software to enable this specific use case.
Optimized for Hacking & Integration
Piunora is also great for embedding into your own custom hardware solutions. Its compact form factor and obstruction-free pin headers facilitate the development of expansion boards using cheap, two-layer PCBs—or the mounting of Piunora, up-side down, onto larger PCBs. And with all of its core connectors facing in the same direction, Piunora takes much of the guesswork out of enclosure design as well.
And don’t forget that M.2 connector, which provides the perfect interface for a more compact style of add-on board. If you are feeling hacky, you can use the optional jumper pads to connect the USB Host port directly to the M.2 connector following the industry standard M.2 B-Key pinout. That way you can develop simple, space-efficient, USB-enabled MCU solutions that extended the functionality of your Piunora. Please note that this is a feature intended for hackers and it might not work perfectly in all situations.
And finally, there are three additional GPIOs connected from the CM4 itself.
Features & Specifications
Ard R3 / Adafruit Metro compatible form factor (3.3 V logic, may not be compatible with all Shields)
PCI-e through M.2 B-Key connector on the rear of the board with dedicated 3.3 V / 3 A supply
Analog to Digital Converter (MCP3008)
On-the-fly switching between USB host (USB Type-A) and device mode (USB Type-C)
Qwiic/Stemma QT connector to easily interface with I²C devices
A full-sized camera connector that supports all Pi-compatible cameras
A full-sized HDM1 2.0 port
A WS2812 Smart RGB LED for user status
Optional Wi-Fi or eMMC options depending on your choice of CM4
Slim design with the Piunora Lite measuring 8-12 mm and the Piunora Pro measuring 11-13 mm
Two user-controllable buttons (including software that turns one of them into a safe-shutdown button)
Piunora is open hardware, and we will publish both our design files and our software by the time it ships
Differences Between Piunora Pro & Piunora Lite
Piunora Lite uses the exact same PCB as Piunora Pro but leaves off the bottom side components for space and cost savings. Piunora Lite does not include the following features: