Category Archives: Aggregated

The GuitarBot will strum you a song

via Arduino Blog

While many Makers have musical skill, others attempt to compensate for their lack of it by producing automatic instruments that play themselves. One such attempt started in 2015 as a collaborative project between three University of Delaware professors as part of an initiative known as “Artgineering.” This was meant to “create a public spectacle… to demonstrate that engineering and art can work together harmoniously.”

Although many would consider engineering to be an art in itself, if you’d like to create your own robotic band, this Instructables write-up for the GuitarBot is a great place to start.

The guitar-playing robot is comprised of three major components: the brains, a strummer, and a chord mechanism. An Arduino Mega, a specially-ordered PCB and several shields are used for control, and a series of solenoids press down frets as needed. Finally, strumming is handled by a pick that is pulled by a DC motor and belt assembly, all of which is held up by an aluminum frame.

Levitate liquids and other tiny objects with this DIY device

via Arduino Blog

If you’ve ever wished you could levitate tiny drops of liquid, small solids, or insects in mid-air, new research has you covered. That’s because Asier Marzo, Adrian Barnes, and Bruce W. Drinkwater have developed a 3D-printed, Arduino Nano-controlled acoustic levitator.

Their device uses two arrays of 36 sonic transducers in a concave pattern, which face each other in order to suspend objects like Styrofoam, water, coffee and paper in between. Several items can even be trapped at the same time, and liquid is inserted into the “levitation zone” via a syringe.

The principle is similar to the vibration you feel when next to a large speaker, but in this case, the homemade levitator employs ultrasonic waves to push particles without causing any damage to humans.

Acoustic levitation has been explored in hundreds of studies for applications in pharmaceuticals, biology or biomaterials. It holds the promise of supporting innovative and ground-breaking processes. However, historically levitators have been restricted to a small number of research labs because they needed to be custom-made, carefully tuned and required high-voltage. Now, not only scientists but also students can build their own levitator at home or school to experiment and try new applications of acoustic levitation.

If you’d like to make your own, be sure to check out Marzo’s Instructables post or the team’s full paper on the experiment here.

Raspbian Stretch has arrived for Raspberry Pi

via Raspberry Pi

It’s now just under two years since we released the Jessie version of Raspbian. Those of you who know that Debian run their releases on a two-year cycle will therefore have been wondering when we might be releasing the next version, codenamed Stretch. Well, wonder no longer – Raspbian Stretch is available for download today!

Disney Pixar Toy Story Raspbian Stretch Raspberry Pi

Debian releases are named after characters from Disney Pixar’s Toy Story trilogy. In case, like me, you were wondering: Stretch is a purple octopus from Toy Story 3. Hi, Stretch!

The differences between Jessie and Stretch are mostly under-the-hood optimisations, and you really shouldn’t notice any differences in day-to-day use of the desktop and applications. (If you’re really interested, the technical details are in the Debian release notes here.)

However, we’ve made a few small changes to our image that are worth mentioning.

New versions of applications

Version 3.0.1 of Sonic Pi is included – this includes a lot of new functionality in terms of input/output. See the Sonic Pi release notes for more details of exactly what has changed.

Raspbian Stretch Raspberry Pi

The Chromium web browser has been updated to version 60, the most recent stable release. This offers improved memory usage and more efficient code, so you may notice it running slightly faster than before. The visual appearance has also been changed very slightly.

Raspbian Stretch Raspberry Pi

Bluetooth audio

In Jessie, we used PulseAudio to provide support for audio over Bluetooth, but integrating this with the ALSA architecture used for other audio sources was clumsy. For Stretch, we are using the bluez-alsa package to make Bluetooth audio work with ALSA itself. PulseAudio is therefore no longer installed by default, and the volume plugin on the taskbar will no longer start and stop PulseAudio. From a user point of view, everything should still work exactly as before – the only change is that if you still wish to use PulseAudio for some other reason, you will need to install it yourself.

Better handling of other usernames

The default user account in Raspbian has always been called ‘pi’, and a lot of the desktop applications assume that this is the current user. This has been changed for Stretch, so now applications like Raspberry Pi Configuration no longer assume this to be the case. This means, for example, that the option to automatically log in as the ‘pi’ user will now automatically log in with the name of the current user instead.

One other change is how sudo is handled. By default, the ‘pi’ user is set up with passwordless sudo access. We are no longer assuming this to be the case, so now desktop applications which require sudo access will prompt for the password rather than simply failing to work if a user without passwordless sudo uses them.

Scratch 2 SenseHAT extension

In the last Jessie release, we added the offline version of Scratch 2. While Scratch 2 itself hasn’t changed for this release, we have added a new extension to allow the SenseHAT to be used with Scratch 2. Look under ‘More Blocks’ and choose ‘Add an Extension’ to load the extension.

This works with either a physical SenseHAT or with the SenseHAT emulator. If a SenseHAT is connected, the extension will control that in preference to the emulator.

Raspbian Stretch Raspberry Pi

Fix for Broadpwn exploit

A couple of months ago, a vulnerability was discovered in the firmware of the BCM43xx wireless chipset which is used on Pi 3 and Pi Zero W; this potentially allows an attacker to take over the chip and execute code on it. The Stretch release includes a patch that addresses this vulnerability.

There is also the usual set of minor bug fixes and UI improvements – I’ll leave you to spot those!

How to get Raspbian Stretch

As this is a major version upgrade, we recommend using a clean image; these are available from the Downloads page on our site as usual.

Upgrading an existing Jessie image is possible, but is not guaranteed to work in every circumstance. If you wish to try upgrading a Jessie image to Stretch, we strongly recommend taking a backup first – we can accept no responsibility for loss of data from a failed update.

To upgrade, first modify the files /etc/apt/sources.list and /etc/apt/sources.list.d/raspi.list. In both files, change every occurrence of the word ‘jessie’ to ‘stretch’. (Both files will require sudo to edit.)

Then open a terminal window and execute

sudo apt-get update
sudo apt-get -y dist-upgrade

Answer ‘yes’ to any prompts. There may also be a point at which the install pauses while a page of information is shown on the screen – hold the ‘space’ key to scroll through all of this and then hit ‘q’ to continue.

Finally, if you are not using PulseAudio for anything other than Bluetooth audio, remove it from the image by entering

sudo apt-get -y purge pulseaudio*

The post Raspbian Stretch has arrived for Raspberry Pi appeared first on Raspberry Pi.

Fridge Compressor to 2-Stroke Engine: JB Weld for the Win

via hardware – Hackaday

We like this one because it has a real Junkyard Wars feel to it: turning a cast-off fridge compressor into a two-stroke internal combustion engine. [Makerj101] is doing this with tooling no more complicated than a hacksaw and a hand drill. And JB Weld — lots and lots of JB Weld.

[Makerj101]’s video series takes us through his entire conversion process. Despite the outward similarity between compressors and engines, there are enough crucial differences to make the conversion challenging. A scheme for controlling intake and exhaust had to be implemented, the crankcase needed to be sealed, and a cylinder head with a spark plug needed to be fabricated. All of these steps would have been trivial in a machine shop with mill and lathe, but [Makerj101] chose the hard way. An old CPU heat sink serves as a cylinder head, copper wire forms a head gasket and spacer to decrease the compression ratio, and the old motor rotor serves as a flywheel. JB Weld is slathered everywhere, and to good effect as the test run in the video below shows.

Think you recognize [Makerj101]? You probably do, since we featured his previous machine shop-less engine build. This guy sure gets his money’s worth out of a tube of JB Weld.

Thanks to [Gregg Eshelman] for the tip.


Filed under: hardware, misc hacks

Getting control over a 50 watt CO2 laser cutter from China

via Dangerous Prototypes

weekend-box

Unboxing laser cutter Co2 50 watt from China:

There are people around me who think I’m crazy. And they are probably right. Who else would buy a machine from someone he does not know. I have to pay upfront. It is not clear how things will get delivered, what gets delivered, or if it gets delivered at all. Up to the point I can lose the money I have spent. Best of all: that machine is dangerous enough to potentially kill me. And it has the potential to put my home on fire too. Well, that sounds like an exciting weekend project, or not?

See the full post at MCU on Eclipse homepage.

Community Profile: David Pride

via Raspberry Pi

This column is from The MagPi issue 55. You can download a PDF of the full issue for free, or subscribe to receive the print edition in your mailbox or the digital edition on your tablet. All proceeds from the print and digital editions help the Raspberry Pi Foundation achieve its charitable goals.

David Pride’s experiences in computer education came slightly later in life. He admits to not being a grade-A student: he left school with few qualifications, unable to pursue further education at university. There was, however, a teacher who instilled in him a passion for computers and coding which would stick with him indefinitely.

David Pride The MagPi Raspberry Pi Community Profile

David joined us at the St James’s Palace community celebration, mingling with the likes of the Duke of York, plus organisers of Jams and clubs, such as Grace and Femi

Welcome to the Community

Twenty years later, back in 2012, David heard of the Raspberry Pi – a soon-to-be-released “new little marvel” that he instantly fell for, head first. Despite a lack of knowledge in Linux and Python, he experimented and had fun. He found a Raspberry Jam and, with it, Pi enthusiasts like Mike Horne and Peter Onion. The projects on display at the Jam were enough to push David further into the Raspberry Pi rabbit hole and, after working his way through several Python books, he began to take steps into the world of formal higher education.

David Pride The MagPi Raspberry Pi Community Profile

David’s determination to access and complete further education in computing has earned him a three-year PhD studentship. Not bad for a “lousy student”

Back to School

With a Mooc qualification from Rice University under his belt, he continued to improve upon his self-taught knowledge, and was fortunate enough to be accepted to study for a master’s degree in Computer Science at the University of Hertfordshire. With a distinction for his final dissertation, David completed the course with an overall distinction for his MSc, and was recently awarded a fully funded PhD studentship with The Open University’s Knowledge Media Institute.

David Pride The MagPi Raspberry Pi Community Profile

Self-playing xylophones, Wiimote air drums, Lego sorters, Pi Wars robots, and more. David is continually hacking toys, giving them new Pi-powered life

Maker of things

The portfolio of projects that helped him to achieve his many educational successes has provided regular retweet material for the Raspberry Pi Twitter account, and we’ve highlighted his fun, imaginative work on this blog before. His builds have travelled to a range of Jams and made their way to the Raspberry Pi and Code Club stands at the Bett Show, as well as to our birthday celebrations.

David Pride The MagPi Raspberry Pi Community Profile

“Pi & Chips – with a little extra source”

His website, the pun-tastic Pi and Chips, is home to the majority of his work; David also links to YouTube videos and walk-throughs of his projects, and relates his experiences at various events. If you’ve followed any of the action across the Raspberry Pi social media channels – or indeed read any previous issues of The MagPi magazine – you’ll no doubt have seen a couple of David’s projects.

David Pride The MagPi Raspberry Pi Community Profile 4-Bot

Many readers will have come across the wonderful 4-Bot before, and it has even made an appearance alongside David in a recent Bloomberg interview. Considering the trillions of possible game positions, David made a compromise and, if you’re lucky, you may just be able to beat it

The 4-Bot, a robotic second player for the family game Connect Four, allows people to go head to head with a Pi-powered robotic arm. Using a Python imaging library, the 4-Bot splits the game grid into 42 squares, and recognises them as being red, yellow, or empty by reading the RGB value of the space. Using the minimax algorithm, 4-Bot is able to play each move within 25 seconds. Believe us when we say that it’s not as easy to beat as you’d hope. Then there’s his more recent air drum kit, which uses an old toy found at a car boot sale together with a Wiimote to make a functional air drum that showcases David’s toy-hacking abilities… and his complete lack of rhythm. He does fare much better on his homemade laser harp, though!

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