Linux Fu: Marker Is A Command Line Menu

October 24, 2018 by 21 Comments

The command line. You either love it or hate it, but if you do anything with a Unix-like system you are going to have to use it eventually. You might find marker — a system billed as a “command palette for the terminal” — a useful program to install. We couldn’t decide if it was like command history on steroids or more of a bookmark system. In a way, it is a little of both.

Your history rolls off eventually and also contains a lot of small commands (although you can use the HISTIGNORE variable to ignore particular commands). With marker, you save specific commands and they stay saved. There are no extra commands nor do the ones you save ever roll off.

Of course, you could just make a shell script or an alias if that’s all there was to it. Marker lets you add a description to the command and then you can search through the commands and the descriptions using a fuzzy incremental search. In addition, you can put placeholders into your command lines that are easily replaced. There are some built-in commands to get you started and the same bookmarks will work in bash and zsh, if you use both.

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This Synth Plays The Only Scale Everybody Knows

October 24, 2018 by 19 Comments

[randomprojectlab] is building a synthesizer around the pentatonic scale for the Hackaday Prize. It’s the Pentasynth, and it’s basically just a keyboard with five notes per scale.

There’s something common to every form of music. Nearly every musical tradition, from western art music, to Indonesian folk music makes use of a pentatonic scale. This is just a major scale without fourth and seventh scale degrees, or just playing the black keys on a piano.  It’s the one scale everybody knows, and forms the basis of every school of thought for music education. Noodling over the pentatonic scale is what all the cool guys do in Guitar Center. It’s absolutely the foundation of all music.

The hardware for this build is an Adafruit Metro Mini, or basically an Arduino with an ATMega328. This generates three channels of audio, two square waves — one each for the keyboard and bass accompaniment — and a pseudo-random noise drum beat. The keys are 3D printed, and the enclosure is CNC’s acrylic.

Most educational music toys out there have a few additional bits to make composing music easier. The Pentasynth is no exception, with a button that adds a drum beat, a button that adds a bassline, and a switch that makes the keyboard major or minor. It’s a great idea, and you can check out a video of the Pentasynth in action below.

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Friday Hack Chat: Air Hacking

October 24, 2018 by 1 Comment

The field of soft robotics sure seems a lot less mature than your standard servo motor and metal framed robot arms. Maybe that’s because building a robot to flex is harder, and maybe it’s because the best methods of constructing soft robotics have only been around for a decade or so. Maybe, though, it’s because it’s hard to control air.

For this week’s Hack Chat, we’re going to be discussing Air Hacking with [Amitabh Shrivastava]. [Amitabh] is a grad student at ITP, NYU studying creative technology, where he makes interactive art, tools for research, and experiments with various materials. Lately he has been developing Programmable-Air, a pneumatic controller for soft robotics. We’ve seen his work at ThiMaker Faire, and it’s an awesome project in this year’s Hackaday Prize.

In this chat we will be talking about DIY soft robotics. Soft robotics is a growing field with a lot of low hanging fruits within grasp of the hobbyist maker. In addition to sharing experience and resources about building your own soft robots, we will talk about actuation! Tune in to see how you can use pneumatics in your next project.

During this week’s Hack Chat, we’ll be discussing:

  • Pneumatics
  • Programmable Air
  • Soft Robotics
  • Methods of adding pneumatics to your project

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Air Hacking Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Friday, October 26th, at noon, Pacific time. If time zones got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Camera Obscura On Wheels Hits The Open Road

October 24, 2018 by 19 Comments

A camera obscura is a very simple device. Consisting of a dark chamber, with only a pinhole to let light in, it focuses an image on its inside surface. If you want to take a permanent copy, it’s as simple as installing a photosensitive film inside and managing the exposure time. Sounds like a normal camera, right? The difference is the scale —  a camera obscura is large enough that humans can stand inside and view the image. Usually, they are large stationary rooms. [Physics Girl] took the show on the road by building a camera obscura out of a rented box truck.

The optics of the camera obscura project an image upside-down.

The basic concept is a great one – hire a box truck, and cover the rear opening with cardboard. Cut a small hole in the cardboard, and you’ve created a camera obscura on wheels. The video does a great job of explaining the optical principles behind what’s happening, and there’s even experimentation around how to change the exposure level and focus through modification of the aperture.

The only downside to viewing a camera obscura on video is that you can’t appreciate the resolution and detail visible in real life. Trust us though, it’s better than any HDTV on the market today.

The rolling camera obscura makes for a great experiment which requires little more than some cardboard, tape, and a sunny day. It would be great fun to execute as an educational activity at a school or makerspace. Once you’ve tackled that, perhaps consider the digital version. Video after the break.

[Thanks to Baldpower for the tip!]

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GE’s Engine To Reignite Civil Supersonic Flight

October 24, 2018 by 110 Comments

On October 24th, 2003 the last Concorde touched down at Filton Airport in England, and since then commercial air travel has been stuck moving slower than the speed of sound. There were a number of reasons for retiring the Concorde, from the rising cost of fuel to bad publicity following a crash in 2000 which claimed the lives of all passengers and crew aboard. Flying on Concorde was also exceptionally expensive and only practical on certain routes, as concerns about sonic booms over land meant it had to remain subsonic unless it was flying over the ocean.

The failure of the Concorde has kept manufacturers and the civil aviation industry from investing in a new supersonic aircraft for fifteen years now. It’s a rare example of commercial technology going “backwards”; the latest and greatest airliners built today can’t achieve even half the Concorde’s top speed of 1,354 MPH (2,179 km/h). In an era where speed and performance is an obsession, commercial air travel simply hasn’t kept up with the pace of the world around it. There’s a fortune to be made for anyone who can figure out a way to offer supersonic flight for passengers and cargo without falling into the same traps that ended the Concorde program.

With the announcement that they’ve completed the initial design of their new Affinity engine, General Electric is looking to answer that call. Combining GE’s experience developing high performance fighter jet engines with the latest efficiency improvements from their civilian engines, Affinity is the first new supersonic engine designed for the civil aviation market in fifty five years. It’s not slated to fly before 2023, and likely won’t see commercial use for a few years after that, but this is an important first step in getting air travel to catch up with the rest of our modern lives.

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Faux Walkie-Talkie For Comedy Walking Tour Is A Rapid Prototyping Win

October 24, 2018 by 6 Comments

Chances are good that a fair number of us have been roped into “one of those” projects before. You know the type: vague specs, limited budget, and of course they need it yesterday. But you know 3D-printers and Raspberduinos and whatnot; surely you can wizard something together quickly. Pretty please?

He might not have been quite that constrained, but when [Sean Hodgins] got tapped to help a friend out with an unusual project, rapid prototyping skills helped him create this GPS-enabled faux-walkie talkie audio player. It’s an unusual device with an unusual purpose: a comedic walking tour of Vancouver “haunted houses” where his friend’s funny ghost stories are prompted by location. The hardware to support this is based around [Sean]’s useful HCC module, an Arduino-compatible development board. With a GPS module for localization and a VS1053 codec, SD card reader, and a small power amp for the audio end, the device can recognize when the user is within 50 meters of a location and play the right audio clip. The housing is a 3D-printed replica of an old toy walkie-talkie, complete with non-functional rubber ducky antenna.

[Sean]’s build looks great and does the job, although we don’t get to hear any of the funny stuff in the video below; guess we’ll have to head up to BC for that. That it only took two weeks start to finish is impressive, but watch out – once they know you’re a wizard, they’ll keep coming back. Continue reading “Faux Walkie-Talkie For Comedy Walking Tour Is A Rapid Prototyping Win” →

Ford Ka Becomes Diwheel Monster

October 24, 2018 by 27 Comments

If you’ve been to the right events, you’ve seen them before – the cars with an external cage that let the car complete a somersault in the forward direction under heavy braking. They’re impressive, but it’s possible to take things even further. Enter [mastermilo82] and the RollKa.

The RollKa follows on from the RollGolf, which was a straightforward roll car build. Built around a Ford Ka, it eschews the external cage for a more radical design. The Ka has been shortened, and designed to fit within two enormous steel rims which wrap around each side of the car. Additional idler wheels have been welded to the Ka’s roof to enable it to effectively roll within the outer steel rims.

It’s a rather eccentric design, known as a diwheel. We’ve seen impressive electric versions before, but at least at this stage, this project appears to lack any advanced control systems and gets by on sheer luck and welding prowess. The build is still at an early stage, with episode three starting some early movement tests under power. It’s a testament to what can be achieved with a spacious garage and some imagination, and we can’t wait to see what happens next! Video after the break.

[Thanks to Baldpower for the tip!]

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