This Is The Raspberry Pi Robot To Beat All Others

August 29, 2018 by Brian Benchoff 13 Comments

Before the introduction of the Raspberry Pi, building robots was hard. The best solution to turning motors on a chassis was repurposing an old roomba. For the brain, maybe you could throw Linux on a router and move your rover around with an old Linksys. Before that, you could buy a crappy robotics kit, thrown together in a box and sold as an ‘educational kit’. I’m sure there are a few readers out there that built robots by wire-wrapping HC11s.

Now we have 3D printers and Raspberry Pis, and with that comes a golden age of robotics. One of the best robot brains out there is the 8BitRobots Modules from [Tim Wilkinson], an entry for this year’s Hackaday Prize.

The 8BitRobots Modules are made up of a few components, not the least of which is a Pi Zero, a fantastically powerful (for its price) Linux computer that is available for five dollars. With an add-on board, cleverly named the RoBonnet, the Pi Zero gets PWM outputs for servos and ESCs, an H-bridge for motors, TTL serial, encoder inputs, a pressure and temperature sensor, an IMU, a power monitor, and everything else you need for a successful Pi robot.

But hardware is only one part of the equation. If you want to program a robot, you need a software stack that makes everything easy. That’s where the 8BitRobots distributed robot platform comes in. This is a bit of Javascript running on the Pi that allows you to program the robot in Blockly, a Scratch-like graphical programming environment that’s been adapted to run in a web browser. It’s an all-in-one solution to robotics development and programming, and an excellent addition to this year’s Hackaday Prize.

PiPod: A Raspberry Pi Zero Portable Music Player

August 28, 2018 by Ben James 16 Comments

[Bram] wasn’t satisfied with the portable music playback devices that were currently available. He craved an offline music player that had a large storage capacity but found that this was only available in high-end, off-the-shelf options, which were far too expensive. [Bram] decided to make his own, powered by a Raspberry Pi zero. After building an initial prototype, the design was iterated a few times, with the latest version featuring a BOM cost of roughly €80.

The whole project is open source, with hardware and software files available on the project GitHub. A 2.2″ TFT displays the UI, which is of course completely customisable. Everything is squashed into a 3D printed case, which has the smallest form factor possible whilst retaining a decent amount of battery life. The electronics are what you’d expect: a boost converter to produce 5 V for the Pi from the 3.7V battery, a charge controller and a battery protection circuit. As a bonus, the battery voltage is monitored with a 12-bit ADC which reports to the Pi, enabling it to do a safe shutdown at low voltage, and display battery level on the UI.

Since the whole purpose of the device is to play audio, onboard filtered PWM wasn’t going to cut it, so instead a 24-bit DAC talks to the Pi via I2S. The audio player backend is VLC, so there’s support for plenty of different file types. A disc image of the whole system is available with everything pre-configured, and you can even buy the assembled PCB from Tindie.

Want to keep the look and feel of your old iPod? We covered an impressive restoration of a 6th gen model, upgrading the storage and battery significantly.

Rasberry Pi PoE Hat Released

August 26, 2018 by Brian Benchoff 37 Comments

It was announced at the beginning of March, but now the Raspberry Pi Power over Ethernet (PoE) hat is out. Thanks to the addition of a new 4-pin header on the Raspberry Pi 3 Model B+, the Pis can get power from an Ethernet cable, provided you’ve got the setup to deliver PoE.

This is a remarkable bit of engineering, even though it’s just adding Power over Ethernet to a small single board computer. Mechanically, the PoE hat doesn’t increase the 3D bounding box volume of the Raspberry Pi at all. It adds cooling with a fan controlled over I2C. Even more bizarrely, the transformer is mounted in a PCB cutout, and we’re desperate to know how that was specced, designed, and assembled. Yeah, it might just be an add-on for the Raspberry Pi, but there’s some clever work that went into designing it.

The Raspberry Pi gained PoE capability with the introduction of the Raspberry Pi 3 Model B+ last March, a release that did require a slight change to the hardware and pinout of the Raspberry Pi. Compared to the Pi 3 Model B, the Pi 3 Model B+ sports a four-pin header right next to the Ethernet jack and one of the mounting holes. This is the same location of the ‘Run’ header found in the Pi 3 Model B, and probably caused much consternation to anyone who built a hat to take advantage of having a real power button on their Pi.

Nevertheless, what’s done is done, and now we have a real PoE solution for the Raspberry Pi. This is bound to be a boon for anyone who wants to build a Raspberry Pi cluster computer, or anyone who is dropping a few Pis into a server rack that already has PoE hardware.

You can pick up a PoE Pi hat through the usual suspects (Farnell, RS, and other resellers) for $20.

Raspberry Shake Detects Quakes

August 25, 2018 by Bryan Cockfield 18 Comments

The Raspberry Pi’s goal, at least while it was being designed and built, was to promote computer science education by making it easier to access a working computer. What its low price tag also enabled was a revolution in distributed computing projects (among other things). One of those projects is the Raspberry Shake, a seismograph tool which can record nearby earthquakes.

Of course, the project just uses the Pi as a cost-effective computing solution. It runs custom software, but if you want to set up your own seismograph then you’ll also need some additional hardware. There are different versions of the Raspberry Shake, the simplest using a single Geophone which is a coil and magnet. Vibrations are detected by sensing the electric signal generated by the magnet moving within the coil of wire. Other models increase the count to three Geophones, or add in MEMS accelerometers, you can easily whip one of these up on your own bench.

The entire setup will fit nicely on a coffee table as well, making it much smaller (and cheaper) than a comparable professional seismograph. Once all of the Raspberry Shakes around the world were networked together, it gives an accurate, real-time view of seismic activity anywhere you can imagine. If you’ve ever been interested in geology or just want to see where the latest earthquake was, check out their projects. But you don’t need even a Raspberry Pi to see where the earthquakes are, thanks to a Hackaday Prize entry all you need is a Twitter account.

Thanks to [Rich Cochran] aka [AG6QR] for the tip!

Guardin, Guarding The Garden: Turn Raspberry Pi Into A 3rd Eye

August 23, 2018 by Jenny List 16 Comments

If you are a gardener, you’ll know only too well the distress of seeing your hard work turned into a free lunch for passing herbivorous wildlife. It’s something that has evidently vexed [Jim], because he’s come up with an automated Raspberry Pi-controlled turret to seek out invading deer, and in his words: “Persuade them to munch elsewhere”.

Before you groan and sigh that here’s yet another pan and tilt camera, let us reassure you that this one is a little bit special. For a start, it rotates upon a set of slip rings rather than an untidy mess of twisted cables, so it can perfom 360 degree rotations at will, then it has a rather well-designed tilting cage for its payload. The write-up is rather functional but worth persevering with, and he’s posted a YouTube video that we’ve placed below the break.

This is a project that still has some way to go, for example just how those pesky deer are to be sent packing isn’t made entirely clear, but we think it already shows enough potential to be worthy of a second look. The slip ring mechanism in particular could find a home in many other projects.

It’s worth reminding readers that while pan and tilt mechanisms can be as impressive as this one, sometimes they are a little more basic.

Continue reading “Guardin, Guarding The Garden: Turn Raspberry Pi Into A 3rd Eye” →

Cross-Correlation Makes Quick Work Of Ads

August 22, 2018 by Kerry Scharfglass 25 Comments

Once relegated to the proverbial Linux loving Firefox user, ad blocking has moved into public view among increased awareness of privacy and the mechanisms of advertising on the internet. At the annual family gathering, when That Relative asks how to setup their new laptop, we struggle through a dissertation on the value of ad blockers and convince them to install one. But what about mediums besides the internet? Decades ago Tivo gave us one button to jump through recorded TV. How about the radio? If available, satellite radio may be free of The Hated Advertisement. But terrestrial radio and online streams? [tomek] wasn’t satisfied with an otherwise sublime experience listening streaming Polish Radio Three and decided to build a desktop tool to detect and elide ads from the live audio stream.

[tomek] was aware of this hip knowledge domain called Digital Signal Processing but hadn’t done any of it themselves. Like many algorithmic problems the first step was to figure out the fastest way to bolt together a prototype to prove a given technique worked. We were as surprised as [tomek] by how simple this turned out to be. Fundamentally it required a single function – cross-correlation – to measure the similarity of two data samples (audio files in this case). And it turns out that Octave provides it in the box. After snipping the start-of-ad jingle out of a sample file and comparing it to a radio program [tomek] got the graph at the left. The conspicuous spike is the location of the jingle in the audio file.

At this point all that was left was packaging it all into a one click tool to listen to the radio without loading an entire analysis package. Conveniently Octave is open source software, so [tomek] was able to dig through its sources until they found the bones of the critical xcorr() function. [tomek] adapted their code to pour the audio into a circular buffer in order to use an existing Java FFT library, and the magic was done. Piping the stream out of ffmpeg and into the ad detector yielded events when the given ad jingle samples were detected.

[tomek] packaged that tool into a standalone executable, but the gem here is the followup post. After removing ads in the online stream they adapted a RaspberryPi to listen to an FM receiver and remote control their Yamaha tuner over the network. So when the tuner is playing Radio Three the Pi notices and ducks the audio appropriately to avoid those pesky ads. Video of this after the break.

Continue reading “Cross-Correlation Makes Quick Work Of Ads” →

Blink A Pi, Win A Prize

August 21, 2018 by Brian Benchoff 5 Comments

You can plug in a Raspberry Pi, and you can blink a LED. You can visualize data, and now there’s a contest on Hackaday.io to show off your skills. Right now, we’re opening up the Visualize It With Pi contest on Hackaday.io. The challenge? Visualize data with LED strips and panels. Is that ‘data’ actually just a video of Never Gonna Give You Up? We’ll find out soon enough.

The goal of this contest is to combine a Raspberry Pi and its immense processing power and the blinky goodness of LED strips and panels to visualize and interpret data in novel and artistic ways. We’re looking for animation. clarity, and flamboyant flickering. Want some ideas? Check out the World of Light or the American Constitution Candle. We’re looking for the most blinky you can do with a Pi, and yes, there will be prizes.

Prizes

Prizes for the best blinky include, of course, more blinky. The best visualizations from a directly connected sensor, data from an Internet Source, and data from an esoteric data source will each receive some Blinkytape. This is a strip of WS2812b LEDs with an ATMega32u4 embedded on the end. Plug a USB power supply into the Blinkytape, and you get a strip of LEDs in whatever color you want with the ability to push animation frames to the chip on the strip. The Grand Prize winner for this contest will also receive Blinkytile Explorers Kit, a Serpentine LED strip, a LED ring, and two meters of ultra thin LED strip.

Let’s Do This!

The requirements for the contest are simple: just use a Raspberry Pi to drive LED strips or panels, post it as a new project on Hackaday.io, and submit the project to the contest. We’re looking for a full description, source, schematics, and photos and videos of the finished version of the project — do everything you can to show off your work! The contest is open right now, and ends at 08:00 Pacific on October 1st. We know you like to blink those LEDs, so get crackin’.