cm4

It's dire: Raspberry Pi availability tracker is launched

Yesterday André Costa emailed me about his new website, rpilocator.

rpilocator website screenshot as of Jan 31 2022

It's a website to track Raspberry Pi 4 model B, Compute Module 4, Pi Zero 2 W, and Pico availability across multiple retailers in different countries.

In his own words:

This database was created out of frustration trying to locate a Raspberry Pi product in the height of the chip and supply chain shortages of 2021. I got tired of visiting multiple websites every day trying to figure out if there were any Raspberry Pi's in stock. I coded this website in a few days during my spare time and had it hosted on a Raspberry Pi for a couple of weeks before deciding to make it publicly available. This is not hosted on a Raspberry Pi anymore.

Raspberry Pi holds its own against low-cost ARM NAS

Earlier this year, I pitted the $549 ASUSTOR Lockerstor 4 NAS against a homebrew $350 Raspberry Pi CM4 NAS, and came to the (rather obvious) conclusion that the Lockerstor was better in almost every regard.

Jeff Geerling holding Raspberry Pi Radxa Taco NAS board and ASUSTOR Drivestor 4 Pro

Well, ASUSTOR introduced a new lower-cost NAS, the $329 Drivestor 4 Pro (model AS3304T—pictured above), and sent me one to review against the Raspberry Pi, since it make for a better matchup—both have 4-core ARM CPUs and a more limited PCI Express Gen 2 bus at their heart.

Around the same time, Radxa also sent me their new Taco—a less-than-$100 Raspberry Pi Compute Module 4 carrier board with 5x SATA ports, 1 Gbps and 2.5 Gbps Ethernet, an M.2 NVMe slot, and an M.2 A+E key slot. (The Taco will soon be available as part of a kit with a CM4 and case for around $200.)

The specs evenly matched, at least on paper:

Pine64 and Radxa's new Pi CM4-compatible boards

Since the Raspberry Pi was introduced, hundreds of clones have adopted the Pi's form factor (from the diminutive Zero to the 'full size' model B). Often they have better hardware specs, and yet they remain a more obscure also-ran in that generation of Single Board Computer (SBC).

Pine64 SOQuartz and Radxa CM3 in front of Raspberry Pi Compute Module 4

So when I saw Radxa's CM3 and Pine64's SOQuartz, I wanted to see if either would be—as they advertised—'drop in, pin-compatible replacements' for the Raspberry Pi Compute Module 4.

tl;dr: They're not. At least not yet.

Hardware and Specs

Both boards are technically pin-compatible. And both will boot and run (to some extent) on pre-existing Compute Module 4 carrier boards, including Raspberry Pi's official IO Board:

Controlling PWM fans with the Raspberry Pi CM4 IO Board's EMC2301

Noctua 120mm PWM fan connected to Raspberry Pi CM4 IO Board

When I initially reviewed the Compute Module 4 IO Board, I briefly mentioned there's a 4-pin fan connector. It's connected to the Pi's I2C bus using a little PWM chip, the EMC2301.

But wait... what's I2C, what's PWM, and what's so special about a 4-pin fan connector? I'm glad you asked—this post will answer that and show you how you can control a fan connected to the IO Board, like the quiet Noctua NF-P12 pictured above with my IO Board.

If you plug a fan like that into the CM4 IO Board, it will start running full blast, 24x7. If you need that much cooling, that's great, but a lot of times, I don't mind my Pi's CPU getting warmer if it means I can run the fan silent most of the time.

Kubesail's PiBox mini 2 - 16 TB of SSD storage on a Pi

Kubesail Raspberry PiBox mini 2 front side exposed

Many months ago, when I was first testing different SATA cards on the Raspberry Pi Compute Module 4, I started hearing from GitHub user PastuDan about his experiences testing a few different SATA interface chips on the CM4.

As it turns out, he was working on the design for the PiBox mini 2, a small two-drive NAS unit powered by a Compute Module 4 with 2 native SATA ports (providing data and power), 1 Gbps Ethernet, HDMI, USB 2, and a front-panel LCD for information display.

The Hardware

The PiBox mini 2 is powered by the Compute Module 4 on this interesting carrier board:

PiBox mini carrier board with Raspberry Pi Compute Module 4

Face detection for my leaf blower

In the class of 'out there' projects, I recently added a little AI to my leaf blower:

Leaf blower with Raspberry Pi on top for AI ML Machine Vision blasting

The short of it: I have a face detection algorithm running which, when a certain individual enters the field of the Pi's vision, triggers a servo that powers on the blower, releasing a powerful air blast.

Red Shirt Jeff gets blasted by air cannon

I've been wanting to play around with face detection on the Pi for some time, but the Pi Zero I use in most of my camera projects is seriously underpowered for this kind of work.

CM4Ext Nano

So when Harlab (Hardware Laboratory) told me they'd like to send me a CM4Ext Nano board for testing, I thought it'd be the perfect opportunity to play with machine vision on the Pi.

Uptime Lab's CM4 Blade adds NVMe, TPM 2.0 to Raspberry Pi

A few weeks ago, I received two early copies of Uptime.Lab's CM4 Blade.

Uptime Lab's Raspberry Pi CM4 Blade Computer with NVMe SSD

The Blade is built for the Raspberry Pi Compute Module 4, which has the same processor as the Pi 4 and Pi 400, but without any of the built-in IO ports. You plug the CM4 into the Blade, then the Blade breaks out the connections to add some interesting features.

A 1U rackmount enclosure is in the works, and 161 of these boards would deliver:

  • 64 ARM CPU cores
  • up to 128 GB of RAM
  • 16 TB+ of NVMe SSD storage

That's assuming you can find 8 GB Compute Modules—they've been out of stock since launch almost a year ago, and even smaller models are hard to come by. More realistically, with 4 GB models, you could cram in 64 GB of total RAM.

The Wiretrustee SATA Pi Board is a true SATA NAS

In my earlier posts about building a custom Raspberry Pi SATA NAS, and supercharging it with 2.5G networking and OMV, I noted that my builds were experimental only—they were a mess of cables and parts, with a hilariously-oversized 700W PC power supply.

I lamented the fact there was no simple "SATA backplane on a board" for the Raspberry Pi Compute Module 4. But no longer.

Wiretrustee SATA Board for Raspberry Pi OMV NAS

Wiretrustee's SATA Board integrates a SATA controller and data and power for up to four SATA drives with a Raspberry Pi Compute Module 4.

And their entire solution makes for a great little Raspberry Pi-based NAS, using software like OpenMediaVault.

Two Tiny Dual-Gigabit Raspberry Pi CM4 Routers

Since I started testing various PCI Express cards on the Raspberry Pi Compute Module 4, I've been excited to see what new kinds of custom networking devices people would come up with.

Well, after months of delays due to part shortages, both DFRobot and Seeed Studios have come out with their 2-port Gigabit router board designs, and I was happy to receive a sample of each for testing:

DFRobot and Seeed Studios Router Boards with Dual Gigabit Ethernet

The boards are tiny, and even with the Compute Module 4 installed, they are incredibly small—take a look at the entire assembled DFRobot unit, complete with a Raspberry Pi attached:

DFRobot CM4 IoT Router Board with Raspberry Pi CM4 and Quarter