Hackaday Links: April 2, 2017

Toorcamp registration is open. It’s June 20-24th on Orcas Island, Washington.

Hey, you. The guy still using Mentor Graphics. Yeah, you. Siemens has acquired Mentor Graphics.

CNC knitting machines are incredibly complicated but exceptionally cool. Until now, most CNC knitting machines are actually conversions of commercial machines. Beginning with [Travis Goodspeed] and  [Fabienne Serriere] hack of a knitting machine, [Becky Stern]’s efforts, and the Knitic project, these knitting machines are really just brain transplants of old Brother knitting machines. A few of the folks from the OpenKnit project have been working to change this, and now they’re ready for production. Kniterate is a project on Kickstarter that’s a modern knitting machine, and basically a 2D woolen printer. This is an expensive machine at about $4500, but if you’ve ever seen the inside of one of these knitting machines, you’ll know building one of these things from scratch is challenging.

There was a time when a Macintosh computer could play games. Yes, I know this sounds bizarre, but you could play SimCity 2000, Diablo, and LucasArts adventure games on a machine coming out of Cupertino. [Novaspirit] wanted to relive his childhood, so he set up a Mac OS 7 emulator on a Raspberry Pi. He’s using Minivmac, beginning with an install of OS 7.1, upgrading that to 7.5.3, then upgrading that to 7.5.5. It should be noted the utility of the upgrade to 7.5.5 is questionable — the only real changes from 7.5.3  to 7.5.5 are improved virtual memory support (just change some emulator settings to get around that) and networking support (which is difficult on an emulator). If you’re going to upgrade to 7.5.5, just upgrade to 8.1 instead.

It’s getting warmer in the northern hemisphere, and you know what that means: people building swamp coolers. And you know what that means: people arguing about the thermodynamics of swamp coolers. We love these builds, so if you have a swamp cooler send it on in to the tip line.

The Prusa edition of Slic3r is out. The improvements? It’s not a single core app anymore (!), so slicing is faster. It’s got that neat variable layer slicing. Check out all the features.

It takes at least a week to delete your Facebook account. In the meantime, you can lawyer up and hit the gym. Additionally, we’re not really sure Facebook actually deletes your profile when you disable your account. Robots to the rescue. [anerdev] built a robot to delete all his content from Facebook. It’s a pair of servos with touchpad-sensitive pens. Add an Arduino, and you have a Facebook deleting machine.

The 35 Year Music Synthesizer That Spawned Chiptune

If you are a certain age, MOS6581 either means nothing to you, or it is a track from Carbon Based Lifeforms. However, if you were a Commodore computer fan 35 years ago, it was a MOS Technologies SID (Sound Interface Device). Think of it as a sound “card” for the computers of the day. Some would say that the chip — the power behind the Commodore 64’s sound system — was the sound card of its day. Compared to its contemporaries it had more in common with high-end electronic keyboards.

The Conversation has a great write up about how the chip was different, how it came to be, the bug in the silicon that allowed it to generate an extra voice, and how it spawned the chiptune genre of music. The post might not be as technical as we’d do here at Hackaday, but it does have oscilloscope videos (see below) and a good discussion of what it took to create music on the device.

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Easy-Peasy Heart Monitor

If you’re at all into medical hacks, you’ve doubtless noticed that the medical industry provides us with all manner of shiny toys to play with. Case in point is a heart-monitoring IC that’s so brand new, it’s not even available in all of the usual distributors yet. [Ashwin], who runs a small prototyping-supplies company, ProtoCentral, has been playing around with the new MAX30003 ECG chip, and the results look great.

The punchline is that the four-to-five dollar chip does everything for you, including analog filtering, wander removal, and even detecting the pulse rate. Using the chip is simple: you plug in two electrodes on one end, and you get the waveform data out over SPI on the other, with little or no work to do on the microprocessor side. The Arduino in the examples is just passing the SPI data straight to the laptop, with no processing going on at all.

[Ashwin] is selling these as breakout boards, but everything is open source, from the hardware to the GUI, so check it out if you’re interested in building your own. In particular, the circuit is just a voltage regulator and five volt level shifter.

Everything we know about electrocardiography projects, we learned from this presentation, and it looks like the devil is in the (many) details, so it’s nice to offload them to custom silicon whenever possible. We just think it’s awesome that we can scoop up some of the giant medical industry’s crumbs to play around with.

VCF East: Before There Was Arduino, We Had Balls

Today, if you want to teach kids the art of counting to one, you’re going to drag out a computer or an iPad. Install Scratch. Break out an Arduino, or something. This is high technology to solve the simple problem of teaching ANDs and ORs, counting to 0x0F, and very basic algorithms.

At the Vintage Computer Festival East this year, System Source, proprietors of a fantastic museum of not-quite-computing equipment brought out a few of their best exhibits. These include mechanical calculators, toys from the 60s, and analog computers that are today more at home in a CS departments’ storage closet than a classroom. It’s fantastic stuff, and shows exactly how much you can learn with some very cleverly designed mechanical hardware.

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Musical string shooter

Musical String Shooter Makes Sound Visible

One reason we really like [Rulof]’s hacks is that he combines the most unlikely things to create something unexpected. This time he makes a fast-moving loop of cotton string undulate in time to music.

To do this he uses cotton string, hard drive parts, two wheels from a toy Ferrari, two DC motors, a plastic straw,  a speaker, and an amplifier.  The loop of string sits in the air by being rapidly rotated in between the two wheels. The hard drive parts, driven by the amplifier, give the string a tap with an amplitude, and at a time determined by the music. The result is music made visible in the air in front of you, or in his living room in this case. Check out how he made it, and see it in action in the video below the break.

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VCF: 3D Printing In The 80s

The Vintage Computer Festival East is going down right now, and I’m surrounded by the height of technology from the 1970s and 80s. Oddly enough, Hackaday frequently covers another technology from the 80s, although you wouldn’t think of it as such. 3D printing was invented in the late 1980s, and since patents are only around for 20 years, this means 3D printing first became popular back in the 2000’s.

In the 1970s, the first personal computers came out of garages. In the early 2000s, the first 3D printers came out of workshops and hackerspaces. These parallels pose an interesting question – is it possible to build a 1980s-era 3D printer controlled by a contemporary computer? That was the focus of a talk from [Ethan Dicks] of the Columbus Idea Foundry this weekend at the Vintage Computer Festival.

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Cordless Water Pump!

A water pump is one of those items that are uncommonly used, but invaluable when needed. Rarer still are cordless versions that can be deployed at speed. Enter [DIY King 00], who has shared his build of a cordless water pump!

The pump uses an 18 volt brushed motor and is powered by an AEG 18V LiPo battery. That’s the same battery as the rest of [DIY King]’s power tools, making it convenient to use. UPVC pipe was used for the impeller — with a pipe end cap for a housing. A window of plexiglass to view the pump in motion adds a nice touch.

A bit of woodworking resulted in the mount for the pump and battery pack, while a notch on the underside allows the battery to lock into place. Some simple alligator clips on the battery contacts and the motor connected through a switch are all one needs to get this thing running.

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