A Raspberry Pi CM5 Carrier Board with Zero Footprint Penalty
ARK’s Just A Pi carrier board matches the Raspberry Pi Compute Module 5 footprint perfectly to pack more power into ultra-tight spaces.
If you’ve chosen a Raspberry Pi Compute Module 5 to use in your hardware design, that decision was probably influenced in no small part by the tiny footprint of this module. This compact form factor makes it possible to hide lots of computing power in a very small space. However, once you attach the module to a carrier board, the size typically increases significantly.
A new carrier board developed by ARK Electronics called Just A Pi was designed to address this problem. It attaches to the rear of the Compute Module 5 and perfectly matches its footprint. If you were to look from the front, you might think that it was, well — just a Pi. Despite the fact that it’s barely visible, the Just A Pi board packs in a lot of features.
The board is especially useful for robotics, drones, and autopilot systems, where space and weight are at a premium. To support those applications, the board replaces many of the bulky connectors typically found on Raspberry Pi carrier boards with compact JST-GH and FFC connectors commonly used in professional robotics hardware.
A built-in Ethernet switch provides support for two external Ethernet connections through JST-GH connectors. Rather than relying on standard RJ45 jacks, which would dramatically increase the overall size, ARK opted for lightweight interfaces better suited to embedded systems. The onboard switch is based on a Microchip KSZ8794 chip and supports two 10/100 Mbps Ethernet ports.
The board also exposes a generous amount of I/O considering its dimensions. Multiple JST-GH headers provide access to UART, SPI, PWM, and GPIO signals, making it easy to interface with flight controllers, sensors, and other peripherals. There is also a PCIe connector that follows the Raspberry Pi 5 pinout, dual MIPI CSI camera connectors, a Micro HDMI output, USB-C with USB 3.0 support, and a dedicated USB 2.0 connector.
A fan connector matching the Raspberry Pi 5 standard is included, while power is supplied through a 6-pin Molex CLIK-Mate connector. ARK recommends a 5 V supply capable of delivering at least 2 A, though actual requirements will depend on the attached peripherals.
The carrier board is primarily intended for the Raspberry Pi Compute Module 5, though ARK notes that limited Compute Module 4 compatibility is available. The MicroSD card slot is functional only when using Lite variants of the CM4 or CM5 that do not include onboard eMMC storage.
Just A Pi is available now for $335 as a standalone carrier board, or $475 bundled with a Raspberry Pi Compute Module 5 Lite, a 64 GB microSD card, and ARK's preconfigured software image.