Argon One M.2 case for the Raspberry Pi 4 by Argon40

Last week I installed an alternate image on my Raspberry Pi 3 Model B - the recently available SDRPlay image. I have the (rather excellent, in my opinion) RSPdx SDR receiver, and I'm in the process of migrating as many radio-related applications as I can over to the Pi as part of a wider logical reorganisation of my setup.

All went well, but I quickly found the CPU temperature hitting some fairly alarming numbers when using Cubic SDR for more than a few minutes. That was all the excuse I needed to spend some money on an upgrade. I guess I could have just opted for an active cooling solution, but as a new Raspberry Pi is small enough to get past an unsuspecting wife, it was a virtually guilt-free foregone conclusion.

I've always liked the look of the Argon Pi cases as they appear to be really well engineered, so one of the M.2 versions quickly followed an 8GB RPi 4B into the PiHut shopping basket as well as a WD Green 240GB M.2 SATA SSD and an official PSU. Then the difficult bit - waiting for it to arrive.

Now this may seem daft. I know how big a Raspberry Pi is, but I was still surprised to see the size of the Argon case. Somehow, Internet reviews made it literally more of a 'big' deal in my mind. Pleasantly surprised though, as I had partly justified the purchase on the compact and robust nature of the thing with one eye on a transportable setup.

The Pi 4 is what it is, so I won't linger here. It's much faster and more capable than my 3B, so I just want to cover the very straightforward marriage with the Argon One M.2 (which confusingly also carries 'Argon40' branding - it turns out that this is the name of the company).

The Argon basically comes in three parts. The metal 'lid' for want of a better name, the base, which houses the SSD module (which won't take an NVMe SSD by the way, only Key-B and Key B&M) and a daughterboard which relocates two full sized HDMI ports and the audio socket to the back of the unit.

The top half is definitely where most of your £40 goes. It relocates the USB-C power socket to the rear panel, the GPIO pins to the top rear of the case, acts as a sizeable heat sink, and houses a small cooling fan.

Underside of the Argon One Raspberry Pi case lid

Joining the two components together - Raspberry Pi with the Argon One HDMI daughterboard

Assembly (and that's all this is really - a simple, modular project) is guided by a well written and clearly illustrated manual which is worth stepping through as you go. Firstly, the HDMI board plugs into the side of the Pi, and then the inverted assembly drops into the top half of the case, sandwiching two silicon thermal pads (supplied). It's at this point that you realise just how well made this enclosure is - everything lines up just as you would hope, and with nice tight tolerances; GPIO pins, all the PCB-mounted hardware at what is now the rear of the device, and all the screw holes. It's precision-cast alloy and beautiful to work with and handle.

Fitting the Raspberry Pi and HDMI board

It feels heavy and never gives you any concern that you're close to stripping a screw thread. The small detachable metal flap which covers the external GPIO array snicks satisfyingly into place on a couple of magnetic pads. It just puts a smile of contentment on your face. The GPIO pins are all very well labelled and I suspect that the legend won't be rubbing off anytime soon. The pinouts are usefully colour-coded too.

New GPIO pin arrangement

One of the selling points of the Argon is also one of the downsides of the Raspberry Pi itself, and that is the process of powering the device on and off. Yanking a wire out and plugging it back in again is not where I want to be. The Argon has a high quality push-button power switch at the rear, which is subsequently integrated into the completed system via a small software tweak, and it works like you'd expect. Short click to power on, click and hold to power off. Double click also does a soft reboot. Nice touch. There is a jumper on the upper PCB to effectively disable this, so that the Pi will boot as soon as power is applied to the board if you so wish. Based on the use you're putting your Pi to, this could clearly be a distinct advantage, but not for general 'desktop' use I feel. It could of course be very useful if you're running a remote station. An IR sensor/receiver is also added to the Pi's already feature-packed specification, allowing use of Argon's own remote control (an optional extra). I'm sure somebody will have a use for that in the media-center world perhaps.

Finishing up this little project, is the optional M.2 SSD installation. Not required, but I have an irrational fear of future regret, so blowing another £30 on a 240GB SSD in the Argon's basement just sounded like a prudent future-proofing policy.

M.2 SATA SSD baseplate.

Construction of the plastic base was again more than adequate, but didn't have the same metallic sensory titillation as the lid. If it had, I'd probably be criticising it for being unnecessary. Fitting the drive was straightforward, although the securing screw, which was already located where you see it in the photo prior to the memory module being fitted, came away from the PCB with the brass standoff attached. That should clearly go underneath the drive, but I bet a lot get installed incorrectly because of this minor niggle.

Argon One M.2 Rear Panel with Power button, 1 x USB 3, 2 x USB 2, Gigabit Ethernet Port, power, audio and HDMI ports

Final steps are to fit your microSD card of choice (Sandisk Ultra Class 10 all the way here) pre-loaded with your software, fit the remaining screws and rubber feet, and plug in the USB3 plug thing. The what? Yeah, that's what connects the two halves together electronically. It means you effectively lose a USB3 port, but gain a SSD so that's fair enough.

Maybe you also noticed that at no point did we plug anything into the USB-C power port on the Pi itself. Cleverly, the power is now delivered by some internal magic - I'm guessing via the GPIO pins and the previously mentioned USB-C port round the back - so you can still use the factory 3A power supply.

Changing the microSD card just became a screwdriver-based operation, but that's probably the only real drawback with this case. There is a slot in the upper housing to feed through the ribbon cable for the Pi camera, though I've not tried this yet.

The end result is a tough, compact and very capable little machine which would stack up well against Linux laptops of just a few years ago. Ideal for a field day or just a little portable messing around if you can find a suitable monitor solution. I know small touchscreens are available for example. I'll be testing and evaluating the setup over the next couple of weeks, and may write some of that up if I think it's of interest,

Berni M0XYF