Raspberry Pi

1842 Articles

Rack ’em Stack ’em Raspberry Pi Controller Board

August 12, 2020 by 14 Comments

It isn’t that hard to assemble an array of Raspberry Pi boards and there are several reasons you might want to do so. The real trick is getting power to all of them and cooling all of them without having a mess of wires and keeping them all separated. The ClusterCTRL stack lets you stack up to five Raspberry Pi boards together. The PCB aligns vertically along the side of the stack of Pis with sockets for each pin header. Using a single 12 to 24V supply, it provides power for each board, a USB power connection, and provisions for two fans. There is also a USB port to control the fans and power.

There’s also a software component to deliver more granular control. Without using the software, the PI’s power on in one second and monitor a GPIO pin to control the fans. With the software, you can turn on or off individual nodes, gang the two fans to turn on together, and even add more stacks.

There is a case that you can print from STL files, although you can buy them preprinted on the Tindie listing where the bulk of information on ClusterCTRL is found. You could also have a 3D printing vendor run off a copy for you if you’d rather.

The power supply is a 10A 5.1V DC to DC converter. That works out to 2A per Pi and 51W total. The power supply for the input, then, needs to be enough to cover 51W, the power for the fans, and some overhead for regulator inefficiency and other small overhead.

We’ve seen a lot of Pi clusters over the years including one that is a good learning tool for cluster management. Of course, there’s always the Oracle cluster with 1,060 boards, which is going to take a bigger power supply.

Folding Raspberry Pi Enclosure Prints In One Piece, No Screws In Sight

August 11, 2020 by 14 Comments

[jcprintnplay] has challenged himself to making Raspberry Pi cases in different ways, and his Fold-a-Pi enclosure tries for a “less is more” approach while also leveraging the strong points of 3D printing. The enclosure prints as a single piece in about 3 hours, and requires no additional hardware whatsoever.

The design requires no screws or other fasteners, and provides a mounting hole for a fan as well as some holes for mounting the enclosure itself to something. All the ports and headers are accessible, and the folding one-piece design is not just a gimmick; in a workshop situation where the Pi needs to be switched out or handled a lot, it takes no time at all to pop the Raspberry Pi in and out of the enclosure.

Microsoft’s 3D Builder has a pretty useful measurement tool for STLs.

[James] points out that the trick with a print-in-place hinge like this is leaving enough space between the parts so that the two pieces aren’t fused together, but not so much space that the print fails. He doesn’t go into detail about how much space worked or didn’t work, but an examination of the downloadable model shows that the clearance used looks like 0.30 mm, intended to be printed with a 0.4 mm nozzle.

[James] also demonstrates the value of being able to do quick iterations on a design when prototyping. In a video (embedded below) The first prototype had the hinge not quite right. In the second prototype there was a lack of clearance when closing. The third one solved both and shows the final design.

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Raspberry Pi Gets PATA/IDE Drive Via GPIO Header

August 10, 2020 by 36 Comments

By and large, the Raspberry Pi is a computer that eschews legacy interfaces. Primarily relying on SD cards for storage and USB ports for further expansion, magnetic hard drives are a rare sight. However, [Manawyrm] decided that some 40-pin goodness was in order, and set to making a PATA IDE adapter for the platform.

To achieve the task of interfacing now-vintage IDE devices with the Raspberry Pi, [Manawyrm] elected to use the single board computer’s GPIO pins to get the job done. 23 pins are required, with 16 used for the data bus, with the rest dedicated to address lines, strobes, and other features.

The adapter is no speed demon, netting 800 KiB/s on reads and 500 KiB/s on writes with a Raspberry Pi 4. The main bottleneck comes from relying on libgpiod, which [Manawyrm] readily admits is designed for general IO tasks, not data transfers. Despite this, it’s still fast enough to play an audio CD from an IDE CD-ROM drive without skipping. A kernel build is required, however, as Raspberry Pis are unsurprisingly not configured to use ATA disks by default.

Obviously, more serious applications would substitute a dedicated USB hard disk adapter or give the Raspberry Pi a PCI-express (PCIe) card for sata drives instead, but that doesn’t discount the fun inherent in the build. While it may be slow, it shows that talking to PATA hard disks is actually quite straightforward when you understand the basics. Of course, if you want to do the opposite, and have your Raspberry Pi emulate a PATA disk, that’s possible too. Video after the break.

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The Zero Terminal 3: A Pop-Out Keyboard Linux Computer In Your Pocket

August 10, 2020 by 35 Comments

The mobile phone revolution has delivered us attractively packaged and convenient computing in our pockets, but without the easy hackability we like in our community. Meanwhile the advent of single board computers has given us affordable super-powerful hardware that can run a very capable GNU/Linux operating system and fulfill all our hackable computing needs. Combine the two though? Plenty have tried, few have succeeded in making something as slick as the former with the open power of the latter. Fine if you like your portable devices to have a cyberdeck vibe, but maybe not something you’d take into the boardrooom. Never fear though, for [N-O-D-E] have the solution, in version 3 of the Zero Terminal. It’s the ultimate in Raspberry Pi based handheld computing, and it resembles a slightly chunky mobile phone.

At its heart is a Waveshare OLED 5.5″ touch screen, on the back owhich is mounted a PCB that carries a USB hub and power circuitry. A Pi Zero is mounted directly to this, and a cleverly designed HDMI adapter board interfaces it to the display. The power board is a generic one, the one designed for the PCB proved difficult to hand solder. There’s a very smartly designed case to give it that mobile phone feel, and on the back are a set of sockets with all the relevant Pi connections. This opens the possibility of some exciting add-ons, the first of which is a sliding keyboard similar to those on early Android phones. The ‘board is based on a [Bobricius] design, though sadly isn’t quite working yet.

As you can see in the video below the break, this is about as slick a mobile Pi as it’s possible to get. [N-O-D-E], we want one. Just take our money!

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Unbricking A $2,000 Exercise Bike With A Raspberry Pi Zero And Bluetooth Hacks

August 4, 2020 by 17 Comments

Really, how did we get the point in this world where an exercise bike can be bricked? Such was the pickle that [ptx2] was in when their $2,000 bike by Flywheel Home Sports was left without the essential feature of participating in virtual rides after Peloton bought the company. The solution? Reverse engineer the bike to get it working with another online cycling simulator.

Sniffing Flywheel Bluetotooth packets with Bluetility

We have to admit we weren’t aware of the array of choices that the virtual biking markets offers. [ptx2] went with Zwift, which like most of these platforms, lets you pilot a smart bike through virtual landscapes along with the avatars of hundreds of other virtual riders. A little Bluetooth snooping with Bluetility let [ptx2] identify the bytes in the Flywheel bike’s packets encoding both the rider’s cadence and the power exerted, which Zwift would need, along with the current resistance setting of the magnetic brake.

Integration into Zwift was a matter of emulating one of the smart bikes already supported by the program. This required some hacking on the Cycling Power Service, a Bluetooth service that Zwift uses to talk to the bike. The final configuration has a Raspberry Pi Zero W between the Flywheel bike and the Zwift app, and has logged about 2,000 miles of daily use. It still needs a motor to control the resistance along the virtual hills and valleys, but that’s a job for another day.

Hats off to [ptx2] for salvaging a $2,000 bike for the price of a Pi and some quality hacking time, and for sticking it to The Man a bit. We have to say that most bike hacks we see around here have to do with making less work for the rider, not more. This project was a refreshing change.

[Featured images: Zwift, Flywheel Sports]

[via r/gadgets]

Facial Detection With Pi + MATLAB

August 4, 2020 by 2 Comments

[Monica] wanted to try a bit of facial detection with her Raspberry Pi and she found some pretty handy packages in MATLAB to help her do just that. The packages are based on the Viola-Jones algorithm which was the first real-time object detection framework for facial detection.

She had to download MATLAB’s Raspbian image to allow the Pi to interpret MATLAB commands over a custom server. That setup is mostly pretty easy and she does a good job walking you through the setup on her project page.

With that, now she can control the Pi in MATLAB: configure the camera, toggle GPIO, etc. The real fun comes with the facial detection program. In addition to opening up a live video feed of the Pi camera, the program outputs pixel data. [Monica] was mostly just testing the stock capabilities, but wants to try detecting other objects next. We’ll see what cool modifications she’s able to come up with.

If MATLAB doesn’t quite fit your taste, we have a slew of facial detection projects on Hackaday.

IOT Pinball Puts Oktoberfest Fun On Tap

August 3, 2020 by 5 Comments

We don’t really miss going out to bars all that much, unless you’re talking about the one downtown with all the pinball machines. Don’t get us wrong — pinball emulators have gotten crazy good, and you can find exact digital replicas of most machines to play on your phone or whatever. But it just doesn’t compare to the thrill of playing a real cabinet.

Don’t despair, because for the next couple of weeks, you can queue up to play on a real Oktoberfest pinball machine that’s sitting in Espoo, Finland. The controls are hooked up to a Raspberry Pi 4 through a custom HAT, along with a camera pointed at the playfield and another focused on the backglass screen. The game development/video streaming company Surrogate is hosting a tournament over the internet, and will be giving prizes to the top ten high rollers.

We usually have to wait until the holiday season to come across these remote-reality gaming opportunities. Having played it several times now, we recommend spamming the flippers until you get a feel for the lag. Also, just holding the flippers up while the ball is in the upper half of the playfield will catch a lot of balls that you might otherwise lose due to flipper lag, and sometimes they end up back in front of the launcher to shoot again. After the break, check out a brief but amusing video of setting up the cameras and Pi that includes a taste of the Oktoberfest music.

The tournament runs until the end of August, which should be enough time for somebody to set up CV and a keyboard to play this automatically. Need inspiration? Here’s an open-source pinball machine that can play itself.

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