Compute Module 4 NAS With Custom Carrier Board

April 8, 2021 by Tom Nardi 20 Comments

At this point, we’ve seen more Raspberry Pi Network Attached Storage (NAS) builds than we can possibly count. The platform was never a particularly ideal choice for this task due to the fact it could only connect to drives over USB, but it was cheap and easy to work with, so folks made the best of it. But that all changed once the Compute Module 4 introduced PCIe support to the Raspberry Pi ecosystem.

If this impressive NAS built by [mebs] represents the shape of things to come, we’re more than a little excited. On the outside, with its 3D printed case and integrated OLED display to show system status, it might look like plenty of builds that came before it. But pop the top of this cyberpunk-styled server, and you realize just how much work went into it.

At the heart of this NAS is a purpose-built carrier board that [mebs] designed based on the KiCad files the Raspberry Pi Foundation released for their official CM4 IO Board. While not much larger than the CM4 itself, the NAS board breaks out the board’s PCIe, Ethernet, HDMI, and USB. There’s also a header for I2C, used primarily for the OLED display but naturally expandable to additional sensors or devices, and nine GPIO pins for good measure.

Of course, that alone doesn’t make a NAS. Into that PCIe port goes a four channel SATA controller card, which in turn is connected to the hard disk drives that are nestled into their respective nodes of the printed case. A central fan blows over the electronics at the core, and thanks to clever design and a few cardboard seals, pulls air over the drives by way of intake vents printed into the sides.

As impressive as this build is, not everyone will need this level of performance. If you don’t mind being limited to USB speeds, you can 3D print a NAS enclosure for the standard Raspberry Pi. Or you could always repurpose an old PC case if you’d like something a bit more substantial.

Fan-tastic Misuse Of Raspberry Pi GPIO

April 6, 2021 by Stephen Ogier 36 Comments

[River] is a big fan of home automation. After moving into a new house, he wanted to assimilate two wirelessly controlled fan lights into his home automation system. The problem was this: although the fans were wireless, their frequency and protocol were incompatible with the home automation system.

Step one was to determine the frequency the fan’s remote used. Although public FCC records will reveal the frequency of operation, [River] thought it would be faster to use an inexpensive USB RTL-SDR with the Spektrum program to sweep the range of likely frequencies, and quickly found the fans speak 304.2 MHz.

Next was to reverse-engineer the protocol. Universal Radio Hacker is a tool designed to make deciphering unknown wireless protocols relatively painless using an RTL-SDR. [River] digitized a button press with it and immediately recognized it as simple on-off keying (OOK). With that knowledge, he digitized the radio commands from all seven buttons and was quickly able to reverse-engineer the entire protocol.

[River] wanted to use a Raspberry Pi to bring the fans into his home automation system, but the Raspberry Pi doesn’t have a 304.2 MHz radio. What it does have is user-programmable GPIO and the rpitx package, which converts a GPIO pin into a basic radio transmitter. Of course, the Pi’s GPIO pin’s aren’t long enough to efficiently transmit at 304.2 MHz, so [River] added a proper antenna, as well as a low-pass filter to clean up the transmitted signal. The rpitx package supports OOK out of the box, so [River] was quickly able get the Pi controlling his fan in no time!

If you’d like to do some more low-cost home automation, check out this approach to using a Raspberry Pi to control some bargain-bin smart plugs.

Raspberry Pi Spigot Puts Digits Of Pi On Tap

April 6, 2021 by Kristina Panos 11 Comments

What did you do for Pi Day? Play with your Raspberry Pi 400? Eat some pizza or other typically round objects and recite all nine digits you’ve got memorized? That’s about where we were at this year. But not [bornach], no. [bornach] went all out and built a spigot that spews digits of Pi well past the first nine decimal places.

This clever spigot sculpture implements the spigot algorithm for generating digits of Pi one-by-one in a stream on to a chain of 8×8 matrices, and does so using a Raspberry Pi (of course). The point of the spigot algorithm is to store as few numbers as possible at any given time by reusing variables. We love the way the digits materialize on the matrix, almost as if they are ink being activated by water. Be sure to check out the build and demo video after the break.

That 10k pot on the top really does control the spigot — since the Pi has no ADC, [bornach] is using the potentiometer to charge a capacitor and using the time it takes to reach the threshold to decide whether the faucet is open or closed. There are a couple of hacks at play here, including the Popsicle-stick LED matrix bracing and the HAT [bornach] fashioned so the daisy-chained 8×8 LED modules could interface with the Pi.

We love Raspberry Pis of all eras around here, especially the darling new Pico. Diminutive as it may be, the Pico can be sliced even smaller with a hacksaw if you don’t mind losing a few GPIO pins.

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Classic Triumph Gets A Modern Digital Dash

March 31, 2021 by Lewin Day 46 Comments

Analog gauges gave way to all manner of fancy electroluminescent and LED gauges in the ’80s, but the trend didn’t last long. It’s only in the last decade or so that LCD digital gauges have really started to take off in premium cars. [Josh] is putting a modern engine and drivetrain into his classic Triumph GT6, and realised that he’d have to scrap the classic mechanical gauge setup. After not falling in love with anything off the shelf, he decided to whip up his own solution from scratch.

The heart of the build is a Raspberry Pi 4, which interfaces with the car’s modern aftermarket ECU via CANBUS thanks to the PiCAN3 add-on board. Analog sensors, such as those for oil pressure and coolant temperature, are interfaced with a Teensy 4.0 microcontroller which has the analog to digital converters necessary to do the job. Display is via a 12.3″ super-wide LCD sourced off Aliexpress, with the graphics generated by custom PixiJS code running in Chromium under X.

The result is comparable with digital displays in many other modern automobiles, speaking to [Josh]’s abilities not just as a programmer but a graphic designer, too. As a bonus, if he gets sick of the design, it’s trivial to change the graphics without having to dig into the car’s actual hardware.

Gauge upgrades are common on restomod projects; another route taken is to convert classical mechanical gauges to electronic drive. If you’re cooking up your own sweet set of gauges in the garage, be sure to drop us a line! Video after the break.

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A Floppy Controller For The Raspberry Pi

March 30, 2021 by Lewin Day 26 Comments

The Raspberry Pi is the darling single board computer that is everything to everyone. It even has lit up the eyes of the older set with the Pi 400 mimicking the all-in-one keyboard computer design so popular in the 1980s. Another project that harkens back to that golden era is this Raspberry Pi floppy controller board from [Dr. Scott M. Baker].

[Scott] is no stranger to floppy controllers, having worked with the popular WD37C65 floppy controller IC before with the RC2014 homebrew Z80 computer. Thus, it was his part of choice when looking to implement a floppy interface on the Raspberry Pi. The job was straightforward, and done with just the IC itself. Despite the Pi running at 3.3 V and the controller at 5 V, [Scott] has found no problems thus far, implementing just a resistor pack to try and limit damage from the controller sending higher voltage signals back to the Pi. With that said, he plans to implement a proper level shifter down the road to ensure trouble-free operation long term.

The project is rounded out with a bunch of Python tools used to interface with the controller, available on Github. Performance is limited by the non-realtime nature of the Raspberry Pi’s user mode operation, which [Scott] notes could be fixed with a kernel module. With that said, if you’re looking for performance, floppies aren’t it anyway.

We do love the Pi put to use in retro tasks; it can even be a SCSI Swiss Army Knife if you need one. Video after the break.

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Data Blaster Is A Hip RPi Cyberdeck

March 25, 2021 by Lewin Day 16 Comments

Cyberdecks were once a science fiction approximation of what computing might look like in the future. In the end, consumer devices took a very different path. No matter, though, because the maker community decided cyberdecks were too awesome to ignore and started making their own. After lusting after some of the amazing builds already out there, [Zach Freedman] decided it was time to start his own build, resulting in the Data Blaster.

Epoxy holds the printed parts to the Pi 400

The Raspberry Pi has always been popular in the nascent cyberdeck scene, providing real Linux computing power in a compact, portable package. Now, we have the Raspberry Pi 400, which is exactly that, built into a shell that is, approximately, half of a cyberdeck. This formed the base of [Zach]’s build, coming in handy with its full-sized keyboard.

To that, he added a widescreen 1280×480 LCD, wearable display, and a USB powerbank, turning it into a true go-anywhere terminal. The 3D-printed handles are a particularly nice touch, making it easy to use the deck from a standing position, something that no laptop really does well. As a bonus, there’s even a tiny software defined radio on the side, complete with a collapsible antenna for that added cool factor.

It’s a fun build, and a useful one too. We suspect the chunky plastics and grabbable design might actually make the Data Blaster preferable to a laptop in rugged field use versus a more traditional laptop. We’ve seen some other great work in this area, too. Video after the break.

A Raspberry Pi Tablet, With A DSI Screen

March 24, 2021 by Jenny List 36 Comments

Since the Raspberry Pi arrived back in 2012, we’ve seen no end of interesting and creative designs for portable versions of the little computer. They often have problems in interfacing with their screens, either on the very cheap models using the expansion port or on more expensive ones using an HDMI screen with associated controller and cabling. The official Raspberry Pi touchscreen has made life easier with its DSI convector, but as [jrberendt] shows us with this neat little tablet, there are other DSI-based options. This one uses a 5″ DSI touchscreen available through Amazon as well as a Pi UPS board to make a tablet that is both diminutive and self-contained.

Having fooled around ourselves in the world of Pi tablets we like this one for its clean look and a bezel that is little bigger than the screen itself. As is the case with so many Pi tablets though it has to contend with the bulk of a full-sized Model B board on its behind, making it more of a chunky brick than a svelte tablet. The screen has potential though, and we can’t help wondering whether there’s any mileage in pairing it with a much thinner Pi Zero board and a LiPo board for a slimmer alternative.

Probably the nicest Pi tablet we’ve brought you was this one, which managed to remain impressively slim despite its HDMI screen.