A Lot Of Effort For A Pi Laptop

April 13, 2021 by Bryan Cockfield 7 Comments

Building a Raspberry Pi laptop is not that uncommon. In fact, just a few clicks from any of the major electronics suppliers will have the parts needed for such a project speeding on their way to your house in no time at all. But [joekutz] holds the uncontroversial belief that the value in these parts has somewhat diminishing returns, so he struck out to build his own Pi laptop with a €4 DVD player screen and a whole lot of circuit wizardry to make his parts bin laptop work.

The major hurdle that he needed to overcome was how to power both the display and the Pi with the two small battery banks he had on hand. Getting 5V for the Pi was easy enough, but the display requires 8V so he added one lithium ion battery in series (with its own fuse) in order to reach the required voltage. This does make charging slightly difficult but he also has a unique four-pole break-before-make switch on hand which doesn’t exactly simplify things, but it does make the project function without the risk of short-circuiting any of the batteries he used.

The project also makes use of an interesting custom circuit which provides low voltage protection for that one lonely lithium battery as well. All in all it’s a master course in using some quality circuit-building skills and electrical theory to make do with on-hand parts (and some 3D printing) rather than simply buying one’s way out of a problem. And the end result is something that’s great for anything from watching movies to playing some retro games.

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An RP2040 Board Designed For Machine Learning

April 13, 2021 by Lewin Day 30 Comments

Machine learning (ML) typically conjures up ideas of fancy code requiring oodles of storage and tons of processing power. However, there are some ML models that, once trained, can readily be run on much more spartan hardware – even a microcontroller! The RP2040, star of the Raspberry Pi Pico, is one such chip up to the task, and [Arducam] have announced a board aiming to employ it to those ends – the Pico4ML.

The board goes heavy on the hardware, equipping the RP2040 with plenty of tools useful for machine learning tasks. There’s a QVGA camera on board, as well as a tiny 0.96″ TFT display. The camera feed can even be streamed live to the screen if so desired. There’s also a microphone to capture audio and an IMU, already baked into the board. This puts object, speech, and gesture recognition well within the purview of the Pico4ML.

Running ML models on a board like the Pico4ML isn’t about robust high performance situations. Instead, it’s intended for applications where low power and portability are key. If you’ve got some ideas on what the Pico4ML could do and do well, sound off in the comments. We’d probably hook it up to a network so we could have it automatically place an order when we yell out for pizza. We’ve covered machine learning on microcontrollers before, too – with a great Remoticon talk on how to get started!

Hamster Goes On Virtual Journey

April 9, 2021 by Bryan Cockfield 19 Comments

Hamsters are great pets, especially for those with limited space or other resources. They are fun playful animals that are fairly easy to keep, and are entertaining to boot. [Kim]’s hamster, [Mr. Fluffbutt], certainly fits this mold as well but [Kim] wanted something a little beyond the confines of the habitat and exercise wheel and decided to send him on a virtual journey every time he goes for a run.

The virtual hamster journey is built on an ESP32 microcontroller which monitors the revolutions of the hamster wheel via a hall effect sensor and magnet. It then extrapolates the distance the hamster has run and sends the data to a Raspberry Pi which hosts a MQTT and Node.js server. From there, it maps out an equivalent route according to a predefined GPX route and updates that information live. The hamster follows the route, in effect, every time it runs on the wheel. [Mr Fluffbutt] has made it from the Netherlands to southeastern Germany so far, well on his way to his ancestral home of Syria.

This project is a great way to add a sort of augmented reality to a pet hamster, in a similar way that we’ve seen self-driving fish tanks. Adding a Google Streetview monitor to the hamster habitat would be an interesting addition as well, but for now we’re satisfied seeing the incredible journey that [Mr Fluffbutt] has been on so far.

Three-Piece Cyberdeck Plays The Role Of Military Computer That Never Was

April 8, 2021 by Dan Maloney 15 Comments

While we’re not at all sick of the cyberdeck movement yet, we do have to admit that some of the builds we see are starting to fall into categories that are beginning to seem a little familiar. The clamshell aesthetic comes to mind, but really, with spaces for a display and a keyboard, the form factor is pretty much a natural for cyberdecking. Which is why we like this three-piece twist on the cyberdeck concept so much.

Like many cyberdeck builds, inspiration for the awesomely mustachioed [Max]’s deck came from the military surplus world. As the story goes, he has a smallish clamshell case that once held radio tools and supplies for the Bundeswehr. Figuring it would make the perfect case for half of a split keyboard, he tracked down a couple more of the sturdy aluminum cases and got to work. As a mechanical keyboard aficionado, [Max] already had PCBs that would fit into two of the cases, so he populated those with suitably clicky switches, came up with cool-looking faceplates, and connected the two boxes with retractile cables. The third case got a Raspberry Pi 4 with a trimmed-down heatsink, a battery and power management, and a generous touchpad and LCD panel display. A Kali Linux install completes the tacticool look.

The three-piece cyberdeck looks very cool when all wired up together, but [Max] needed one more piece to really sell it. So he 3D-printed a slipcase for all three units; painted in military colors and suitably distressed, the whole thing really just works. We’ve seen a lot of cyberdecks lately in all sorts of styles, but this one really pleases.

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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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