Raspberry Pi Makes A Practical Tricorder

August 24, 2020 by Al Williams 3 Comments

What do you get when you add a thermal camera, a software-defined radio dongle, and a battery to a Raspberry Pi? If you are [saveitforparts] you make a tricorder for sniffing radio signals and viewing heat signatures. He admits, the videos (see below) aren’t exactly a “how-to” but it will still give you some ideas for your next build.

You can sense the frustration with some Linux configuration issues, but [saveitforparts] admits he isn’t a Linux or Raspberry Pi guru. Version 1 seemed to be a bit of a prototype, but version 2 is more polished. We still aren’t sure we’d see Spock carrying a case like that, but some 3D printing could spiff that right up.

Of course, a real tricorder is a McGuffin that does whatever the plot calls for. This one is a bit more practical, but it can monitor thermal and RF energy and could accommodate more sensors. This is a great example of a project that would have been very hard to do in the past but is much easier today. The availability of cheap computers and ready-made modules along with associated software open up many possibilities.

If you want to do your own Tricorder hacking you could take over a commercial model. Then again, there’s an official replica on its way that seems like it might have some similar features.

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Student Rover Explores The Backyard In Tribute

August 21, 2020 by Al Williams 3 Comments

Three students were a little sad when NASA’s Opportunity rover went silent after 15 years on the Martian surface. So they decided to build their own rover inspired by Opportunity to roam their backyards using an off-the-shelf robot chassis, a Raspberry Pi, and the usual list of parts like motors, H-bridges, and batteries.

Like the real rover, the vehicle uses a rocker-bogie system, although it is a little less complex than the version NASA sent blasting off towards the Red Planet. The plucky vehicle comes complete with miniature solar panels to recharge its onboard battery, courtesy of some dollar-store garden lights. A pair of videos after the break show how the rover is controlled, as well as the view sent back from its onboard camera.

The rover ran a simulated Mars mission as part of a school project where it had to find an object and transmit an image of it back to home base, and by the looks of it, is was a rousing success. But the young explorers aren’t resting on their laurels, and are already working on a second version of their exploration vehicle that can operate in inclement weather and includes some new tools such as a robotic arm and infrared illumination for low-light imaging.

We’ve seen plenty of Mars rover clones in the past, but there’s always room for more. Of course, if you’re looking for something a bit easier to start with, you can always go the LEGO route.

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Rack ’em Stack ’em Raspberry Pi Controller Board

August 12, 2020 by Al Williams 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 Donald Papp 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 Lewin Day 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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Generate Positivity With Machine Learning

August 6, 2020 by Bryan Cockfield 4 Comments

Gesture recognition and machine learning are getting a lot of air time these days, as people understand them more and begin to develop methods to implement them on many different platforms. Of course this allows easier access to people who can make use of the new tools beyond strictly academic or business environments. For example, rollerblading down the streets of Atlanta with a gesture-recognizing, streaming TV that [nate.damen] wears over his head.

He’s known as [atltvhead] and the TV he wears has a functional LED screen on the front. The whole setup reminds us a little of Deep Thought. The screen can display various animations which are controlled through Twitch chat as he streams his journeys around town. He wanted to add a little more interaction to the animations though and simplify his user interface, so he set up a gesture-sensing sleeve which can augment the animations based on how he’s moving his arm. He uses an Arduino in the arm sensor as well as a Raspberry Pi in the backpack to tie it all together, and he goes deep in the weeds explaining how to use Tensorflow to recognize the gestures. The video linked below shows a lot of his training runs for the machine learning system he used as well.

[nate.damen] didn’t stop at the cheerful TV head either. He also wears a backpack that displays uplifting messages to people as he passes them by on his rollerblades, not wanting to leave out those who don’t get to see him coming. We think this is a great uplifting project, and the amount of work that went into getting the gesture recognition machine learning algorithm right is impressive on its own. If you’re new to Tensorflow, though, we have featured some projects that can do reliable object recognition using little more than a Raspberry Pi and a camera.

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IOT Pinball Puts Oktoberfest Fun On Tap

August 3, 2020 by Kristina Panos 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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