open-hardware carrier board for the Radxa CM5

More I/O than a Pi 5,
in 100 mm.

Dual 2.5 GbE, native NVMe, optional PoE, 6 TOPS NPU — on a 4-layer board that fits in your palm. Designed in KiCad, assembled by JLCPCB, open-sourced under CERN-OHL-P v2.

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  • 100mmBoard size
  • 8-coreRK3588S2
  • 2×2.5GEthernet
  • $99Target price

features

Why NodePad exists

The Pi 5 is great. This is better for homelabs. More cores, more Ethernet, native NVMe, and PoE — all on a 100mm square board.

>>

Dual 2.5 GbE

One built into the CM5, second via RTL8125BG. Run it as a router, K3s node, or dedicated cluster interconnect.

[NVMe]

Native NVMe

M.2 M-key 2280 slot on-board. Real SSDs, no microSD lottery, no HAT required.

[PoE]

PoE+ Optional

Populate the MP8007 PD circuit for 802.3at 25W. Leave it off for cheaper builds. One cable does power + data.

USB-C

USB-C PD Input

CH224K negotiates 12V/15V/20V from any PD charger. No barrel jack, no wall wart.

6T

6 TOPS NPU

The RK3588S2's built-in NPU for edge AI, object detection, and local inference workloads.

mm

100 × 100 mm

Cheapest JLCPCB tier. Fits in a 3D-printed cube smaller than a Pi 5. Stack four of them.

the spec sheet

NodePad vs Pi 5

Side by side, the numbers speak for themselves.

Feature Pi 5 NodePad (CM5)
CPU 4× Cortex-A76 @ 2.4 GHz 8× (4×A76 + 4×A55) @ 2.4 GHz
GPU VideoCore VII Mali-G610 MP4
NPU — 6 TOPS
Max RAM 8 GB 16 GB
Ethernet 1× 1 GbE 2× 2.5 GbE
NVMe Via HAT Native M.2 on-board
PoE HAT (~$20) On-board (optional)
Boot microSD eMMC on module

// two SKUs

Pick your NodePad

Same 100×100mm 4-layer PCB scaffold. Different I/O composition.

NodePad

Base

The general-purpose homelab node. HDMI, 4× USB 3.0, WiFi slot, and a single 2.5GbE uplink.

  • 1× 1 GbE + 1× 2.5 GbE
  • 1× M.2 M-key NVMe (2280)
  • 1× M.2 E-key WiFi/BT (2230)
  • 1× HDMI 2.0
  • 4× USB-A 3.0
  • 40-pin GPIO (Pi-compatible)
  • PoE footprint (DNP)
Empty board $99
+ CM5 4GB / 32GB $169
+ CM5 8GB / 64GB $199
+ CM5 16GB / 128GB $249
Get notified
Networking

NodePad-Net

Pro

The network appliance. Triple Ethernet, SFP cage, headless — built for routers, firewalls, and K3s clusters.

  • 1× 1 GbE + 2× 2.5 GbE
  • 1× SFP cage (1G SGMII)
  • 1× M.2 M-key NVMe (2280)
  • No HDMI (headless)
  • 2× USB-A 3.0
  • PoE footprint (DNP)
Empty board $129
+ CM5 4GB / 32GB $199
+ CM5 8GB / 64GB $229
+ CM5 16GB / 128GB $279
Get notified

overview

A carrier board for the Radxa CM5

You skip designing the CPU/RAM/eMMC section (Radxa already did that) and get a compact server-class SBC with I/O aimed at self-hosting, homelab, mini-Kubernetes, edge servers, network appliances, and NAS-lite.

The pitch

Think of it as a "buy 4, stack them, run K3s on PoE" kind of board. Two 2.5 GbE ports, native NVMe, optional PoE — all on a 100mm square that costs less than a Pi 5.

Why not just a Pi 5?

The Pi 5 gives you 1 GbE and requires a HAT for NVMe. NodePad gives you 2× 2.5 GbE, native M.2 NVMe, optional PoE, 6 TOPS NPU, and 8 cores — in a smaller form factor.

Open hardware

Designed in KiCad, licensed CERN-OHL-P v2. Every file — schematic, PCB, BOM, gerbers, case CAD — will be public. Manufacture your own or buy pre-assembled.

architecture

How it all connects

┌──────────────────────────────────────────┐
│        Radxa CM5 (RK3588S2)             │
│   8-core • 8GB LPDDR4X • 64GB eMMC     │
│   Native: 1 GbE, HDMI, USB3, PCIe, GPIO │
└──┬────┬────┬────┬────┬────┬────┬────────┘
   │    │    │    │    │    │    │
   │    │    │    │    │    │    └── 40-pin GPIO
   │    │    │    │    │    └── HDMI 2.0
   │    │    │    │    └── 4× USB-A 3.0
   │    │    │    └── M.2 E-key (WiFi/BT)
   │    │    └── M.2 M-key (NVMe SSD)
   │    └── RJ45 #1 (1 GbE native)
   └── RTL8125BG → RJ45 #2 (2.5 GbE)

   Power: USB-C PD (12/15/20V) or PoE+ (802.3at)
        └─ MP2315 buck → 5V rail
        └─ AP2112K LDO → 3.3V aux

design rationale

Design decisions

01

PoE is optional

Footprint-only. Populate the MP8007 PD circuit for 802.3at 25W PoE, or leave it off for cheaper builds. One cable does power + data.

02

2.5 GbE, not 1 GbE

RTL8125BG adds a second NIC via PCIe. Enough bandwidth for a router, K3s node, or dedicated cluster interconnect.

03

eMMC, not microSD

Boot from the CM5's onboard eMMC. No microSD lottery, no HAT required. microSD kept as fallback only.

04

USB-C PD input

CH224K negotiates 12V/15V/20V from any PD charger. No barrel jack, no wall wart headache.

05

100 × 100 mm

Cheapest JLCPCB tier. Fits in a 3D-printed cube smaller than a Pi 5. Stack four of them for a cluster.

06

Pi-compatible GPIO

40-pin header with the same pinout as the Pi. Existing HATs and accessories work out of the box.

reality check

What to expect

Hardware takes longer than software. Here's the honest timeline.

Timeline

~3 months part-time to a rev-2 sellable board. Schematic and PCB layout are front-loaded in the first 2–3 weeks.

Rev 1 will have bugs

High-speed routing (2.5 GbE, PCIe Gen 2, USB 3.0) benefits from human review. Plan for at least one rev-2 spin. Every serious hardware product does this.

Comparable products

Turing Pi 2 ($260, 4-node), Radxa Rock 5A ($90 SBC), DeskPi Super6C ($200, CM4-only). NodePad's niche = smallest + PoE + cheap single node.

status

Where we are

Design phase — schematic & PCB not started yet.

Design brief locked

Board outline, stackup, design rules, BOM with LCSC part numbers.

KiCad project scaffold

100×100mm outline, 4× M2.5 mounting holes, 4-layer stackup, net classes.

Schematic capture

Power tree, CM5 connectors, RTL8125 NIC, M.2 slots, USB hub, HDMI, GPIO.

PCB layout & routing

Placement, high-speed routing (PCIe, USB3, 2.5GbE), DRC clean.

Prototype & rev 2

Order 5 from JLCPCB, bring-up, fix bugs, sellable rev 2 spin.

FAQ

Frequently asked

The Radxa CM5 module already has the CPU, RAM, eMMC, and GPU designed in. We skip the ~$1000-per-chip BGA design effort and focus purely on I/O: Ethernet, NVMe, USB, PoE. Faster to market, cheaper to manufacture.

That's the entire point. Buy 4 NodePad-Net boards, connect them via the 2.5GbE ports, power them all with PoE, and you have a 32-core K3s cluster the size of a paperback book.

~3 months part-time to a rev-2 sellable board. Schematic capture and PCB layout are front-loaded in the first 2–3 weeks. Expect at least one rev-2 spin to fix prototype bugs — every serious hardware product does this.

Planning CERN-OHL-P v2 (permissive open-hardware license). KiCad files, gerbers, BOM, and case CAD will all be public. You can manufacture your own or buy pre-assembled.

Those benefit massively from human review before spending money on prototypes. The schematic can be generated, but differential-pair routing for 2.5GbE and PCIe Gen 2 needs careful impedance control. Plan for at least one rev-2 spin.

Turing Pi 2 is $260 for a 4-node CM4 carrier. NodePad is $99 for a single node with better I/O (2.5GbE, NVMe, PoE). Different niches: Turing Pi is a pre-built cluster board; NodePad is a cheap, flexible single node you compose yourself.

get in touch

Follow the build

Prototyping in progress. Drop us a line if you want early access or bulk pricing.

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