Stomping On Microcontrollers: Arduino Mega Guitar Effects Pedal

May 8, 2018 by 18 Comments

Effects pedals: for some an object of overwhelming addiction, but for many, an opportunity to hack. Anyone who plays guitar (or buys presents for someone who does) knows of the infinite choice of pedals available. There are so many pedals because nailing the tone you hear in your head is an addictive quest, an itch that must be scratched. Rising to meet this challenge are a generation of programmable pedals that can tweak effects in clever ways.

With this in mind, [ElectroSmash] are back at it with another open source offering: the pedalSHIELD MEGA. Aimed at musicians and hackers who want to learn more about audio, DSP and programming, this is an open-hardware/open-software shield for the Arduino MEGA which transforms it into an effects pedal.

The hardware consists of an analog input stage which amplifies and filters the incoming signal before passing it to the Arduino, as well as an output stage which does the DAC-ing from the Arduino’s PWM outputs, and some more filtering/amplifying. Two 8-bit PWM outputs are used simultaneously to make pseudo 16-bit resolution — a technique you can read more about in their handy forum guide.

The list of effects currently implemented covers all the basics you’d expect, and provides a good starting point for writing custom effects. Perhaps a library for some of the commonly used config/operations would be useful? Naturally, there are some computational constraints when using an Arduino for DSP, though it’s up to you whether this is a frustrating fact, or an opportunity to write some nicely optimised code.

[ElectroSmash] don’t just do pedals either: here’s their open source guitar amp.

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Mike's robot dog

Mike’s Robot Dog Is A First Step In The Right Direction

May 8, 2018 by 13 Comments

Humans can traverse pretty much any terrain thanks to their legs and fast-acting balancing system. So if you want a robot which should have equal flexibility, legs are a good way to go, this confirmed by all the achievements of Boston Dynamics’ robots. It was therefore natural for [Mike Rigsby] to model his robot dog after Boston Dynamics’ dog-like robot, SpotMini.

The build log on his Hackaday.io page makes for interesting reading. For example, he started out with the legs oriented like SpotMini but found that when trying to stand, the front legs worked fine but the rear ones slid or the dog shifted rearward or both happened. His solution was to take a cue from his 1990s Sony robot dog, Aibo, by reversing the orientation of the rear legs. He then upgraded his servo motors to ones with double the torque and increased the strength of the legs’ structure. In the first video below, you can see that his dog now lifts itself up to a standing position perfectly.

So far, to give it more of a dog-like personality he’s mounted Google’s AIY Vision Kit which changes a light’s color based on the degree to which a person is smiling, though we think a wagging tail would work well too. The possibilities are endless but one step at a time. See the second video below for a demonstration of the use of the Vision Kit.

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Sophie Wilson: ARM And How Making Things Simpler Made Them Faster & More Efficient

May 8, 2018 by 84 Comments

Sophie Wilson is one of the leading lights of modern CPU design. In the 1980s, she and colleague Steve Furber designed the ARM architecture, a new approach to CPU design that made mobile computing possible. They did this by realizing that you could do more, and quicker, with less. If you’ve use a Raspberry Pi, or any of the myriad of embedded devices that run on ARM chips, you’ve enjoyed the fruits of their labor.

It all began for Sophie Wilson with an electric lighter and a slot machine (or fruit machine, as they are called in the UK) in 1978. An aspiring thief had figured out that if you sparked an electric lighter next to the machine, the resulting wideband electromagnetic pulse could trigger the payout circuit. Electronics designer Hermann Hauser had been tasked with fixing the problem, and he turned to Wilson, a student working at his company.

Wilson quickly figured that if you added a small wideband radio receiver to detect the pulse, you could suppress the false payout, foiling the thief. Impressed with this innovation, Hauser challenged Wilson to build a computer over the summer holidays, based in part on a design for an automated cow feeder that Wilson had created at university. Wilson created this prototype computer that looked more like a hand-wired calculator than a modern computer, but the design became the basis for the Acorn System 1, the first computer that Hauser’s new company Acorn Computers launched in 1979. Continue reading “Sophie Wilson: ARM And How Making Things Simpler Made Them Faster & More Efficient” →

We Couldn’t Resist This CNC Batik Bot

May 8, 2018 by 17 Comments

Batik is an ancient form of dyeing textiles in which hot wax is applied to a piece of cloth in some design. When the cloth is submerged in a dye bath, the parts covered with wax resist the pigment. After dyeing, the wax is either boiled or scraped away to reveal the design.

[Eugenia Morpurgo] has created a portable, open-source batik bot that rolls along the floor and draws with wax, CNC-style, on a potentially infinite expanse of cloth. The hardware should be familiar: an Arduino Mega and a RAMPS 1.4 board driving NEMA 17 steppers up and down extruded aluminium.

Traditionally, batik wax is applied with a canting, a pen-like object that holds a small amount of hot wax and distributes it through a small opening. The batik bot’s pen combines parts from an electric canting tool with the thermistor, heater block, and heater cartridge from an E3D V6 hot end. [Eugenia] built the Z-axis from scrap and re-used the mechanical endstops from an old plotter. Check out the GitHub for step-by-step instructions with a ton of clear pictures and the project’s site for even more pictures and information. Oh, and don’t resist the chance to see it in action after the break.

We love a good art bot around here, even if the work disappears with the tide.

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How To Build Anything Out Of Aluminum Extrusion And 3D Printed Brackets

May 8, 2018 by 42 Comments

The real power of 3D printing is in infinite customization of parts. This becomes especially powerful when you combine 3D printing with existing materials. I have been developing a few simple tricks to make generic fasteners and printed connectors a perfect match for aluminum extrusion, via a novel twist or two on top of techniques you may already know.

Work long enough with 3D printers, and our ideas inevitably grow beyond our print volume. Depending on the nature of the project, it may be possible to divide into pieces then glue them together. But usually a larger project also places higher structural demands ill-suited to plastic.

Those of us lucky enough to have nice workshops can turn to woodworking, welding, or metal machining for larger projects. Whether you have that option or not, aluminum extrusion beams provide the structure we need to go bigger and to do it quickly. And as an added bonus, 3D printing can make using aluminum extrusion easier and cheaper.

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Alexa, Attack Intruders

May 8, 2018 by 3 Comments

If our doom at the hands of our robot overlords is coming, I for one welcome the chance to get a preview of how they might go about it. That’s the idea behind Project Icarus, an Alexa-enabled face-tracking Nerf turret. Designed by [Nick Engmann],  this impressive (or terrifying) project is built around a Nerf Vulcan, a foam dart firing machine gun mounted on a panning turret that is hidden behind a drop-down cabinet door. This is connected to a Pi Zero equipped with a Pi camera. The Zero is running OpenCV and Google Firebase, which connects it with Amazon’s Alexa service.

It works like this: you say “Alexa, open Project Icarus”. Through the Alexa skill that [Nick] created, this connects to the Pi and starts the system. If you then say “Alexa, activate alpha”, it triggers a relay to open the cabinet and the Nerf gun starts panning around, while the camera mounted on the top of it searches for faces. The command “Alexa, activate beta” triggers the Nerf to open fire.

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Is That A Tweet On Your Belt Buckle Or Are You Just Happy To See Me?

May 8, 2018 by 8 Comments

What a time to be alive! The range of things you never knew you needed but absolutely must have expands at a breakneck pace, such that it’s now possible to pick up a belt buckle with an embedded LED matrix to scroll messages. We have no idea what the use case for something like this is, but some people will buy anything.

One such person was a friend of [Brian Moreau], who doubled down after being gifted the glowing bauble by turning it into a WiFi enabled Tweet-scrolling belt buckle. It appears to be a just for fun project, and to be honest one would need a heck of a belt for the buckle after his mods. He added an ESP8266 to take care of monitoring his Twitter account and driving the display on the belt buckle, a non-trivial task given that the thing is programmed with only two buttons that scroll through characters to compose a message. The microcontroller might have fit inside the original buckle or only added a little to its bulk, but [Brian] decided to replace the two coin cells powering it with an external 6-volt battery pack. That required a buck converter to power the ESP, so the whole thing ended up being thrown in a case and acting more like a neat display than a flashy fashion statement.

We’d bet some tradeoffs could be made to reduce the bulk and get that buckle back where it belongs, though. Once it does, maybe it’ll be part of a complete LED-laden ensemble, from head to toe.