Raspberry Pi

1501 Articles

Scratch Built Tracked Robot Reporting For Duty

June 17, 2021 by 8 Comments

Inspired by battle-hardened military robots, [Engineering Juice] wanted to build his own remote controlled rover that could deliver live video from the front lines. But rather than use an off-the-shelf tracked robot chassis, he decided to design and 3D print the whole thing from scratch. While the final product might not be bullet proof, it certainly doesn’t seem to have any trouble traveling through sand and other rough terrain.

Certainly the most impressive aspect of this project is the roller chain track and suspension system, which consists of more than 200 individual printed parts, fasteners, bearings, and linkages. Initially, [Engineering Juice] came up with a less complex suspension system for the robot, but unfortunately it had a tendency to bind up during testing. However the new and improved design, which uses four articulated wheels on each side, provides an impressive balance between speed and off-road capability.

Internally there’s a Raspberry Pi 4 paired with an L298 dual H-bridge controller board to drive the heavy duty gear motors. While the Pi is running off of a standard USB power bank, the drive motors are supplied by a custom 18650 battery pack utilizing a 3D printed frame to protect and secure the cells. A commercial night vision camera solution that connects to the Pi’s CSI header is mounted in the front, with live video being broadcast back to the operator over WiFi.

To actually control the bot, [Engineering Juice] has come up with a Node-RED GUI that’s well suited to a smartphone’s touch screen. Of course with all the power and flexibility of the Raspberry Pi, you could come up with whatever sort of control scheme you wanted. Or perhaps even go all in and make it autonomous. It looks like there’s still plenty of space inside the robot for additional hardware and sensors, so we’re interested to see where things go from here.

Got a rover project in mind that doesn’t need the all-terrain capability offered by tracks? A couple of used “hoverboards” can easily be commandeered to create a surprisingly powerful wheeled platform to use as a base.

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2:3 Scale VT100 Terminal Gets Closer To Its Roots

June 15, 2021 by 39 Comments

When [Michael Gardi] finished his scaled down DEC VT100 replica a few months ago, he made it very clear that the project was only meant to look like a vintage terminal on the outside. A peek into the case revealed nothing more exotic than a Raspberry Pi running its default operating system, making the terminal just as well suited to emulating classic games as it was dialing into a remote system. But as any hacker knows, some projects end up developing a life of their own.

It started simply enough. The addition of an RS-232 Serial HAT to the Raspberry Pi meant that the 3D printed VT100 could actually operate as a serial terminal using software such as minicom. Then [Lars Brinkhoff] got involved. He loved the look of the printed VT100, and thought it deserved better than a generic terminal emulator. So he went ahead and started developing a custom terminal simulator for it to run.

Reliving those CRT glory days.

The idea here is that an an 8080 emulator actually runs an original VT100 firmware ROM, warts and all. It makes all the beeps and chirps you’d expect from the real hardware, and there’s even some OpenGL trickery used to mimic an old CRT display, complete with scan lines and a soft glow around characters.

Naturally the visual effects consume a fair amount of processing power, so [Lars] cautions that anything lower than the Pi 4 will likely experience slowdowns. Of course, nothing is stopping you from running the simulator on your desktop machine if you’re looking for that classic terminal experience.

Did this gorgeous recreation of the VT100 need to have a true serial interface or a simulator that recreates the unique menu system of the original? Not at all. Even without those additions, it blew us away when [Michael] first sent it in. But are we happy that these guys have put in the time to perfect this already stellar project? We think you already know the answer.

Raspberry Pi Zero Takes The Wheel In Miniature Fighting Robot

June 12, 2021 by 17 Comments

Looking to capitalize on his familiarity with the Raspberry Pi, [Sebastian Zen Tatum] decided to put the diminutive Pi Zero at the heart of his “antweight” fighting robot, $hmoney. While it sounds like there were a few bumps in the road early on, the tuxedoed bot took home awards from the recent Houston Mayhem 2021 competition, proving the year of Linux on the battle bot is truly upon us.

Compared to using traditional hobby-grade RC hardware, [Sebastian] says using the Pi represented a considerable cost savings. With Python and evdev, he was able to take input from a commercial Bluetooth game controller and translate it into commands for the GPIO-connected motor controllers. For younger competitors especially, this more familiar interface can be seen as an advantage over the classic RC transmitter.

A L298N board handles the two N20 gear motors that provide locomotion, while a Tarot TL300G ESC is responsible for spinning up the brushless motor attached to the “bow tie” spinner in the front. Add in a Turnigy 500mAh 3S battery pack, and you’ve got a compact and straightforward electronics package to nestle into the robot’s 3D printed chassis.

In a Reddit thread about $hmoney, [Sebastian] goes over some of the lessons his team has learned from competing with their one pound Linux bot. An overly ambitious armor design cost them big at an event in Oklahoma, but a tweaked chassis ended up making them much more competitive.

There was also a disappointing loss that the team believes was due to somebody in the audience attempting to pair their phone with the bot’s Pi Zero during the heat of battle, knocking out controls and leaving them dead in the water. Hopefully some improved software can patch that vulnerability before their next bout, especially since everyone that reads Hackaday now knows about it…

While battles between these small-scale bots might not have the same fire and fury of the televised matches, they’re an excellent way to get the next generation of hackers and engineers excited about building their own hardware. We wish [Sebastian] and $hmoney the best of luck, and look forward to hearing more of their war stories in the future.

TV Ambient Lighting Built For Awesome Performance

June 11, 2021 by 34 Comments

[AndrewMohawk] had seen all kinds of ambient lighting systems for TVs come and go over the years, and the one thing they all had in common was that they didn’t live up to his high standards. Armed with the tools of the hacker trade, he set about building an Ambilight-type system of his own that truly delivered the goods.

The development process was one full of roadblocks and dead ends, but [Andrew] persevered. After solving annoying problems with HDCP and HDMI splitters, he was finally able to get a Raspberry Pi to capture video going to his TV and use OpenCV to determine the colors of segments around the screen. From there, it was simple enough to send out data to a string of addressable RGB LEDs behind the TV to create the desired effect.

For all the hard work, [Andrew] was rewarded with an ambient lighting system that runs at a healthy 20fps and works with any HDMI video feed plugged into the TV. It even autoscales to work with video content shot in different aspect ratios so the ambient display always picks up the edge of the video content.

With 270 LEDs fitted, the result is an incredibly smooth and fluid ambient display we’d love to have at home. You can build one too, since [Andrew] shared all the code on Github. As an added bonus, he also gave the system an audio visualiser, and tested it out with some Streetlight Manifesto, the greatest third-wave ska band ever to roam the Earth. The Fourth Wave still eludes us, but we hold out hope.

We’ve seen plenty of hacks in this vein before; one of the most impressive hacked a smart TV into doing the video processing itself. Video after the break.

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Lamp Sheds Light On Air Quality

June 3, 2021 by 4 Comments

It can be difficult to appreciate when the air quality is decent and when it’s poor, unless conditions are so bad that you can literally see the smog hanging in the air. Rather than try to digest a bunch of air quality numbers, [guillaume_slizewicz] built Canari — a lovely lamp that sheds light on the air pollution problem by taking local air quality data and turning it into light patterns.

Canari is of course named after the brave birds that once alerted miners to dangerous air conditions before they were forced to switch to carbon monoxide sensors. This bird has a Raspberry Pi Zero W that gets air quality data from a public API and controls the lights with a PWM bonnet based on the concentration of particulates in the air. The more particulates, the dimmer the LEDs are, and the faster they fade in and out.

The main piece of data that Canari grabs is the amount of particulate matter, and the display can switch between representing the level of PM2.5 (particulate matter with diameter less than 2.5 micrometers)  in the air and PM10. Check out the demo and setup video after the break.

More of a numbers person? All you really need is a microcontroller, an air quality sensor, and a display.

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New Part Day: RP2040 Chips In Single Unit Quantities

June 1, 2021 by 26 Comments

Since the launch of the Raspberry Pi Pico back in January the little board with its newly-designed RP2040 microcontroller has really caught the imagination of makers everywhere, and we have seen an extremely impressive array of projects using it. So far the RP2040 has only been available on a ready-made PCB module, but we have news today direct from Eben Upton himself that with around 600k units already shipped, single-unit sales of the chip are commencing via the network of Raspberry Pi Approved Resellers.

This news will doubtless result in a fresh explosion of clever projects using the chip, but perhaps more intriguingly it will inevitably result in its appearance at the heart of a new crop of niche products that go beyond simple clones of the Pico in different form factors. The special ingredient of those two PIO programmable state machines to take the load of repetitive tasks away from the cores raises it above being merely yet another microcontroller chip, and we look forward to that feature being at their heart.

The Broadcom systems-on-chip that power Raspberry Pi’s existing range of Linux-capable boards have famously remained unavailable on their own, meaning that this move to being a chip vendor breaks further new ground for the Cambridge-based company. It’s best not to think of it in terms of their entering into competition with the giants of the microcontroller market though, because a relative minnow such as the RP2040 will be of little immediate concern to the likes of Microchip, ST, or TI. A better comparison when evaluating the RP2040’s chances in the market is probably Parallax with their Propeller chip, in that here is a company with a very solid existing presence in the education and maker markets seeking to capitalise on that experience by providing a microcontroller with that niche in mind. We look forward to seeing where this will take them, and we’d hope to eventually see a family of RP2040-like chips with different package and on-board peripheral options.

Neural Networks Emulate Any Guitar Pedal For $120

May 30, 2021 by 62 Comments

It’s a well-established fact that a guitarist’s acumen can be accurately gauged by the size of their pedal board- the more stompboxes, the better the player. Why have one box that can do everything when you can have many that do just a few things?

Jokes aside, the idea of replacing an entire pedal collection with a single box is nothing new. Your standard, old-school stompbox is an analog affair, using a combination of filters and amplifiers to achieve a certain sound. Some modern multi-effects processors use software models of older pedals to replicate their sound. These digital pedals have been around since the 90s, but none have been quite like the NeuralPi project. Just released by [GuitarML], the NeuralPi takes about $120 of hardware (including — you guessed it — a Raspberry Pi) and transforms it into the perfect pedal.

The key here, of course, is neural networks. The LSTM at the core of NeuralPi can be trained on any pedal you’ve got laying around to accurately reproduce its sound, and it can even do so with incredibly low latency thanks to Elk Audio OS (which even powers Matt Bellamy’s synth guitar, as used in Muse‘s Simulation Theory World Tour). The result of a trained model is a VST3 plugin, a popular format for describing audio effects.

This isn’t the first time we’ve seen some seriously cool stuff from [GuitarML], and it also hearkens back a bit to some sweet pedal simulation in LTSpice we saw last year. We can’t wait to see this project continue to develop — over time, it would be awesome to see a slick UI, or maybe somebody will design a cool enclosure with some knobs and an honest-to-god pedal for user input!

Thanks to [Mish] for the tip!

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