The Raspberry Pi CM0 Finally Reaches Hobbyists — $33 on AliExpress With eMMC and Wi-Fi

A China-Only Compute Module Quietly Reaches the Global Maker Community

The Raspberry Pi CM0 — the cost-engineered castellated system-on-module that Raspberry Pi originally designed for the Chinese OEM market — is now widely available to global hobbyists through AliExpress resellers, with prices starting at $33 and many sellers reporting several thousand units in stock. CNX Software flagged the development on April 27, 2026, and for the maker community that has been watching the CM0 from a distance since its September 2025 unveil, the AliExpress availability is the first practical path to getting one in hand without setting up a Chinese OEM relationship.

For Raspberry Pi enthusiasts, embedded developers, and hobbyists building compact projects around Raspberry Pi silicon, the CM0 is genuinely interesting. It packages the same RP3A0 system-in-package found in the Raspberry Pi Zero 2 W and the Compute Module 3E into a tiny castellated module — meaning it solders directly onto a custom PCB rather than requiring socket connectors. That form factor is what makes the CM0 attractive for purpose-built hardware projects where a Pi Zero footprint is too large or where a socketed module is too expensive.

What the Raspberry Pi CM0 Actually Is

The CM0 is built around the Raspberry Pi RP3A0 system-in-package, which combines a quad-core 64-bit Arm Cortex-A53 CPU running at 1 GHz with 512MB of LPDDR2 RAM in a single integrated package. That is the same compute profile as the Raspberry Pi Zero 2 W — meaningfully more capable than the original Pi Zero and well-suited to lightweight Linux workloads, embedded applications, and IoT projects.

The module ships with optional 8GB or 16GB eMMC flash storage built in, which removes the need for an external microSD card and meaningfully improves boot reliability and write endurance compared to SD-card-based deployments. Optional 2.4GHz Wi-Fi 4 and Bluetooth 4.2 LE radio variants make the CM0 a complete connected compute module rather than a bare CPU module.

The 132 castellated holes around the perimeter expose the RP3A0's GPIO, USB, camera, display, and other interfaces directly to the carrier PCB. For maker projects that mount the CM0 onto a custom board, this is exactly the integration model that high-volume embedded products have used for years.

Specifications at a Glance

The CM0 lands in the following configuration:

- CPU/RAM: Raspberry Pi RP3A0 SiP — quad-core Cortex-A53 @ 1 GHz, 512MB LPDDR2

- Storage: Optional 8GB or 16GB eMMC flash (also a non-eMMC variant)

- Wireless: Optional 2.4GHz Wi-Fi 4 and Bluetooth 4.2 LE

- Form factor: Castellated module with 132 holes for direct PCB soldering

- Pricing: Starting at $33 on AliExpress, varying by configuration

The price floor of $33 is a markup over the original $18 OEM price for the bare CM0, but it is the first time the module has been practically purchasable in single-unit quantities outside China.

Why This Matters for the Maker and SBC Community

Raspberry Pi's official position when the CM0 launched in September 2025 was that it was a cost-engineered product specifically for the Chinese OEM market with no plans for broader availability. CEO Eben Upton was direct about that positioning. For nine months, the only way to get a CM0 outside China was through finished products that integrated it.

The AliExpress availability changes that calculus. Hobbyists building compact Pi-based projects — handheld devices, embedded sensors, robotics control boards, low-power IoT gateways — now have access to a Raspberry Pi castellated module in single-unit quantities. The form factor is genuinely useful for projects where the Pi Zero 2 W's standard PCB layout is too constraining or where the cost of socketed Compute Modules makes a project economically borderline.

Comparison to the Pi Zero 2 W and CM3E

The CM0 is not a strict upgrade or downgrade compared to the existing Raspberry Pi compact options — it is a different physical form factor for the same compute profile. The Pi Zero 2 W remains the right choice for projects that want a complete board with USB and HDMI connectors. The Compute Module 3E remains the right choice for projects that want a socketed module on a carrier board. The CM0 fills the gap for projects that want to integrate the RP3A0 directly into a custom PCB design, where socketing and external connectors are unwanted overhead.

For hobbyist hardware designers, the castellated form factor is also pedagogically useful. Designing a carrier board for a castellated module is closer to designing a real embedded product than it is to wiring up a Pi Zero with header pins. Projects built around the CM0 are training ground for the kinds of hardware decisions that production embedded products require.

Caveats Worth Knowing

The CM0 is officially sold only in China. The AliExpress channel is reseller-driven, which means availability, configuration mix, and pricing will vary over time as resellers manage their stock. Bulk OEM pricing remains different from the AliExpress retail price.

The eMMC and Wi-Fi-equipped variants are the most practically useful configurations for hobbyist projects. The bare CM0 without eMMC requires booting from external storage, which adds carrier board complexity. The non-Wi-Fi variants narrow the project use cases meaningfully. Single board computer enthusiasts shopping the listings should check the configuration details carefully before ordering.

What to Build With It

The CM0 is well-suited to the projects that the Pi Zero 2 W has historically anchored — but with the form factor flexibility that custom carrier boards provide. Compact handheld retro gaming devices, smart home sensor hubs, robot control boards, low-power network appliances, and embedded display modules all fit cleanly within the CM0's compute envelope.

For makers who have been waiting for a Raspberry Pi castellated module at this price point, the AliExpress channel is the practical answer for spring 2026. The 132-hole footprint is a small but interesting design canvas, and the $33 entry price keeps experimentation cost low even for hobbyist projects that may not reach production.

Sources: CNX Software (April 27, 2026), Hackster.io (September 2025), Jeff Geerling Blog (September 2025), Raspberry Pi Compute Module Zero Product Page