Laser Cut Mechanical Logic Gates

November 23, 2015 by Al Williams 9 Comments

When you create logic circuits using ICs or FPGAs, you can’t easily visualize their operation without special tools. But if you’ve ever seen a mechanical computer (like the Computer History Museum’s Babbage engine) operate, you know you don’t have that problem. Just like it is fascinating to watch a 3D printer or CNC machine, watching mechanical logic gates work can be addictive.

[Anthony] wanted to build some mechanical logic gates and set out designing them using Inkscape. Unlike some common mechanical gate schemes, [Anthony’s] gates use gears to implement the logic operations. He sent the designs off to a laser cutter service and got back parts cut from 3mm acrylic.

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The Ommatid Is An Awesome “Thing”

November 23, 2015 by Elliot Williams 7 Comments

[Jonathan Foote] made a really cool device: the Ommatid spherical display and controller. Part woodworking craft project, part art, and part tremendous hack, the Ommatid is something that we don’t really have a name for. But you can watch it in action, running demo code, in a video below the break.

The sphere design started out with a “20-sided regular polyhedron” with which D&D players should be familiar, and then divided each triangular face into four more triangles. An 80-sided die? Almost. One triangle’s worth was sacrificed for the part that mounts to the base.

Each facet contains an RGB LED and an IR sensor so that it can tell when a hand is nearby. All of this input and output is run through a Raspberry Pi, so both the sensing and display interactions are easily modified. [Jonathan] runs us through the electronics, programming, and interactivity in a separate Instructable. We really like [Jonathan]’s idea of turning this device into an OSC controller / display.

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Laser-cut Cardboard Planetary Gearset Is Pretty, But Useless

November 22, 2015 by Elliot Williams 11 Comments

[Shane] made a project that speaks directly to our heart — combining laser cutting, cardboard, and gears. How could it be any better? Well, it could do anything. But that’s quibbling. It’s fun enough just to watch the laser-cut cardboard planetary gears turn. (Video after the break.)

It was made on a laser cutter using the gear extensions for generating gears in Inkscape, everybody’s favorite free SVG editor.

In his writeup, [Shane] touches on all of the relevant details: all of the gear pitches need to be the same, and the number of teeth in the sun gear (in the center) needs to equal the number of teeth in the ring (outside) divided by the number of planets (orbiting, in the middle). So far so good.

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3D Carver Makes Magnetic Fields Visible

November 19, 2015 by Dan Maloney 10 Comments

The history of science is full of examples when a 3D physical model led to a big discovery. But modelling something that’s actually invisible can be tough. Take magnetic fields – iron filings on a card will give you a 2D model, but a 3D visualization of the field would be much more revealing. For that job, this magnetic field following 3D carving machine is just the thing.

What started out as a rapid prototyping session with servos and hot glue ended up as quick and dirty 3D carving rig for [Frits Lyneborg]. The video shows his thought progression and details how he went from hot glue and sticks to LEGO Technics parts and eventually onto Makerbeam extrusions for the frame of his carver. A probe with a Hall effect sensor is coupled to a motor spinning a bit that cuts into a block of floral foam. A microcontroller keeps the Hall sensor a more or less fixed distance from a rare-earth magnet, resulting in a 3D model of the magnetic field in the foam, as well as a mess of foam nubbles. Despite a few artifacts due to in-flight adjustments of the rig, the field presents clearly in the block as two large lobes.

Carving foam isn’t the only way to visualize a magnetic field in three dimensions, of course. If you’d rather have a light show based on the local magnetic field, try this 3D compass build we covered a while back.

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Hacking Chinese State Media

November 18, 2015 by Brian Benchoff 54 Comments

A while ago, a few journalists from China visited the Metalab hackerspace in Vienna. They wanted to do a story on ‘fablabs’ and ‘makerspaces’, despite the objections to the residents of the Metalab hackerspace. Apparently, mentioning ‘hacking’ on China Central Television (yes, it’s called CCTV) is a big no-no.

Wanting to send a message to at least a few people in China, the members of the hackerspace had to think laterally. Metalab member [amir] came up with a way to encode data that could be printed on t-shirts. These bright, colorful squares featured in all of the interviews with Metalab members carried messages like, “free tibet!”, “remember tian’anmen 1989” and “question the government. dont trust the propaganda”

All the videos are available in this playlist, and [amir]’s code to generate the colorful rectangles of political activism can be found here.

In a related note, we’d like to say ‘hi’ to our one reader in North Korea. Yes, according to the stats and analytics, we have one reader in North Korea.

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Speaker Science Project

November 18, 2015 by Al Williams 10 Comments

They probably won’t please the audiophiles, but [KJMagnetics] shows you that can create a pair of speakers with some magnets, some plastic cups, and a bit of magnet wire. Creating speakers out of junk isn’t a new idea, of course. However, there’s something pleasant about the build. Maybe it is the symmetry of the cups or the workbench look of the woodworking.

We couldn’t help but think that this would make a good science fair project or a classroom activity. Especially since there is a good write up on how speakers work and it would be easy to make simple changes to test different hypothesis about speakers. For example, what happens with more or less wire in the coils? What magnets work best? What does best even mean? Is it louder? Less distortion?

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Old-school Rotary Phone Gets GSM Upgrade

November 18, 2015 by Dan Maloney 12 Comments

Sometimes, the answer to, “Why would you bother with a project like that?” is just as simple as, “Because it’s cool.” We suspect that was the motivation behind [Dirk-Jan]’s project to make portable versions of classic rotary telephones.

On style points alone, [Dirk-Jan] scores big. The mid-1950s vintage Belgian RTT model 56 phone has wonderful lines in its Bakelite case and handset and a really cool flip-up bail to carry it around, making it a great choice for a portable. The guts of the phone were replaced with a SIM900 GSM module coupled with a PIC microcontroller and an H-bridge to drive the ringer solenoids, along with a Li-ion battery and charger to keep it totally wireless – except for the original handset cord, of course. The video after the break show the phone in action both making and receiving calls; there’s something pleasing on a very basic level about the sound of a dial tone and the gentle ringing of the bell. And it may be slow, but a rotary dial has plenty of tactile appeal too.

Rotary-to-cell conversions are a popular “just because” project, like this conversion designed to allow an angry slam-down of the handset. The orange Siemens phone in that project is nice and all, but we really favor the ’50s look for a portable.

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