Delta Bot Plucks Out Tunes On A Mandolin

Is there no occupation safe from the scourge of robotic replacement? First it was the automobile assemblers, then fast food workers, and now it’s the — mandolin players?

Probably not, unless [Clayton Darwin]’s mandolin playing pluck-bot has anything to say about it. The pick-wielding delta-ish robot can be seen in action in the video below, plucking out the iconic opening measures of that 70s prom-theme favorite, “Colour My World.” The robot consists of two stepper motors connected to a hinged wooden arm by two pushrods. We had to slow the video down to catch the motion, but it looks like [Clayton] has worked out the kinematics so that the pick can be positioned in front of any of the mandolin’s eight strings. A quick move of the lower stepper then flicks the pick across a string and plucks it. [Clayton] goes into some detail about how he built the motion-control part in an earlier video; he also proves that steppers are better musicians than we’ll ever be with a little “Axel F” break.

It’s only a beginning, of course, but the complexity of the kinematics just goes to show how simple playing an instrument isn’t. Unless, of course, you unleash an endless waterfall of marbles on the problem.

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Adaptive guitar: pick board and controller

Hackaday Prize Entry: Adaptive Guitar

Due to a skiing accident, [Joe]’s new friend severed the motor nerves controlling her left arm. Sadly she was an avid musician who loved to play guitar — and of course, a guitar requires two hands. Or does it? Pressing the string to play the complex chords is more easily done using fingers, but strumming the strings could be done electromechanically under the control of a foot pedal. At least that’s the solution [Joe] implemented so beautifully when his friend’s family reached out for help.

There are just so many things to enjoy while reading through [Joe]’s project logs on his hackaday.io page, which he’s entered into the Hackaday Prize. He starts out with researching how others have solved this problem. Then he takes us through his first attempts and experiments. For example, an early discovery is how pressing the strings on the fretboard pulls the string down where the picks are located, causing him to rethink his initial pick design. His criteria for the pick actuators leads him to make his own. And the actuators he made are a thing of beauty: quiet, compact, and the actuator body even doubles as part of a heat sink for his custom controller board. During his pick design iterations he gets great results using spring steel for flexibility leading up to the pick, but thinking of someday going into production, he comes up with his own custom-designed, laser-cut leaf springs, different for each string.  Needing Force Sensitive Resistors (FCRs) for the foot pedal, he iterates to making his own, laying out the needed interlinked traces on a PCB (using an Eagle script) and putting a piece of conductive rubber over it all. And that’s just a sample of the adventure he takes us on.

In terms of practicality, he’s made great efforts to make it compact and easy to set up. The foot pedal even talks to the control board on the guitar wirelessly. Non-damaging adhesives attach magnets and velcro to the guitar so that the control board and pick bridge can be precisely, yet easily, attached single-handedly. The result is something easy to manage by someone with only one working hand, both for set-up and actual playing. See it for yourself in the video below.

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Modify Locks To Baffle Burglars

While it’s often thought of as a criminal activity, there’s actually a vibrant hobby community surrounding the art of lock picking. In the same way that white hat hackers try to break into information systems to learn the ways that they can be made stronger, so do those in the locksport arena try to assess the weaknesses of various locks. For the amateur, it can be exciting (and a little unnerving) to experience the ease at which a deadbolt can be picked, and if your concern is great enough, you can go a little farther and modify your locks to make them harder to defeat.

The lock in question was sent to [bosnianbill] by [Rallock67] with a device that [Rallock67] had installed using common tools. Known as a Murphy Ball, a larger-than-normal spring was inserted into one of the pins and held in place by a ball bearing. This makes the lock almost completely immune to bumping, and also made it much more difficult for [bosnianbill], an accomplished and skilled locksmith, to pick the lock due to the amount of force the spring exerted on the cylinder. The surprising thing here was that this modification seems to be relatively easy to do by tapping out some threads and inserting a set screw to hold in the spring.

Locksport and lockpicking are a great hobby to get into. Most people start out picking small padlocks due to their simplicity and ease. It’s even possible to pick some locks with a set of bobby pins. And, if you really want to see how easy it is to defeat some locks and/or how much good the TSA does for your overall security, you’ll want to take a look at this, too.

Thanks to [TheFinn] for the tip!

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Paperclip Lock Picking Sets

Lockpicking has become a trademark skill of hackers all across the world, and is regularly taught at hackerspaces and maker faires. But a lot of the time, the sets have already been made or bought online somewhere. However, [Sean] has demonstrated how to create a lock picking set with ordinary paperclips in the video embedded at the end of this post. Wikihow also has these awesome instructions on how to build them.

What’s great is that the material for these picks are easily found. There are other ways to fashion a set together. For example, street sweeper bristles can be used. And electrical metal tape is a good material as well, but these paperclip sets are, by far, the most accessible. Pretty much anywhere that has office stationary supplies will have mounds of these little metal clips lying around.

But how well do they work? Have you made a paperclip lock picking set before?

If so, let us know in the comments, and tell us how well they did.

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Electronic Guitar Pick Tunes The Strings For You

The Stimmmopped is an electronic guitar tuner made to be used as a guitar pick. This uses two LEDs synchronized to blink at the exact frequency of the string you are tuning. Pluck the string with the corner of the PCB and then shine the light on the string you are tuning. As the vibrating string moves back and forth it will only pick up the spot of light when the frequency matches that of the blinking LED. Once in tune, both red lights will appear to be constantly illuminated and immobile on the string.

An Atmel ATmega8 is used to control the device, interfacing with two buttons and a seven-segment display to choose the pitch currently being tuned. Gibson has a robotic guitar that features an auto-tuning mode, but if you don’t want to shell that much this low cost and simple build is for you.

[Thanks Sören]

Toool Picksets At The Last HOPE

Speaking of laser engraving, the blackbag blog announced that Toool has designed 2 unique picksets for The Last HOPE this year. First is the credit card sized snap-off set seen above. They have named this one The Last HOPE emergency pickset. The other pickset is a new version of the ‘double sided pick’ series. This set consists of picks with the same tool on either end, but they are sized differently. This set will contain 8 picks with promised improvements. If you are interested in more complex picks, check out the centipede.