24-hour Hackathon Produces Respectable Accelerometer Labyrinth

August 29, 2013 by Mike Szczys 12 Comments

hackathon-labyrinth

We’re not sure if this was some type of corporate team building, but if it was sign us up for the next one. [Filipp], [Saluka], and [Michael] participated in a recent 24-hour hackathon hosted by Microsoft. They whipped up this labyrinth game controlled by a Nexus 4 Android phone.

This thing looks so well crafted we’re shocked that it’s a 24-hour build. Just putting together the walls of a maze that size takes some time. They then mounted it in a gimbaled frame which tilts the using servos. Check out the demo video below to get a look at the underpinnings. There are several elastic bands connecting the base to the maze. These act as shock absorbers to help keep the movement smooth and to prevent any oscillations from the frame flexing. For us this is an important design element that we’ll keep in mind (just in case we need to win another competition by designing a labyrinth).

An Arduino controls the servos, using Bluetooth to communicate with the phone. The team mentions some filtering used to help make the user experience more natural but we didn’t see many details on this aspect of the hack.

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Many Iterations Of A Plywood Stool That Requires No Glue

August 29, 2013 by Mike Szczys 36 Comments

cnc-router-stool-design

At his local hackerspace [Vincent Sanders] noticed an interesting problem. The stools that they had were great in most cases, but there was one workbench which was very much the wrong height for them. So began his quest to design and fabricate plywood stools which use no glue for their joints.

The Cambridge Makespace (in the UK) turns out to be a perfect environment for this type of project. They already had a CNC router which can cut the plywood pieces, and there are other members who were willing to help train [Vincent] on the equipment. He found a design on Thingiverse which fit the bill, except for the actual measurements. He needed metric units to match the sheet stock available to him. Once converted he put together a stool that didn’t work at all. The thickness of the plywood just didn’t mesh with the tolerances of the joints. After wandering around to different suppliers in town, digital calipers in hand, he came up with a range of actual thicknesses and adjusted his joint design accordingly.

Of course this wasn’t the last revision. Even with the joints working the seat was still a little rickety. He moved to the next plywood thickness offered, redesigning the files to match. His final stool works like a charm, with five or six of them fitting on one standard sheet of plywood.

Fail Of The Week: Motorizing A PCB Cutting Shear

August 29, 2013 by Mike Szczys 43 Comments

This week’s fail is an attempt to retrofit a PCB cutting shear with a geared motor. The project was undertaken by [David Cook]. Incidentally he’s very near and dear to us as his book Robot Building for Beginners got us started with hacking in the first place.

This $200 shearing tool is hand-operated and can cut through boards up to 1/16″ thick. But [David] really had to crank on the thing to make a cut. This often resulted in crooked board edges. He decided to do the retrofit in order to achieve higher precision. He sourced a high-torque motor from eBay for around $50 delivered.

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As Millenials Grow Up Do They Demand Cooler LED Sneakers?

August 29, 2013 by Mike Szczys 23 Comments

flora-LED-sneakers

We’re hoping that whomever came up with the idea of integrating LEDs into children’s shoes is kicking back on a beach somewhere living off the residuals of the idea. We see those things everywhere. Now the real question is, if you grew up with LEDs in your shoes do you expect cooler light up kicks as you age? [Becky Stern] must think so and that’s why she’s showing off Adafruit’s addressable LED strip shoe project called Firewalker.

This is prototype rather than product, so you can see the Arduino compatible Flora board on the ankle of the lit shoe above. There’s also a battery pack hitching a ride on the laces. But those worried about that fashion faux pas can work on a more finished driver that straps to your calf, or can be integrated in the insole.

Lighting patterns are set off by Velostat, a pressure-sensitive conductive sheet that goes in the heel of the insole. The Flora board measures the resistance, triggering a light show (embedded below) when it drops. Now we just need someone to integrate a power generator based on your movement.

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Primer On Bluetooth Low Energy

August 29, 2013 by Mike Szczys 14 Comments

We’re sure that, like us, you’ve heard at least something about Bluetooth Low Energy (BLE). Blutooth 4.0 is another name for BLE and it’s already available in some smartphones; starting with the iPhone 4S, BlackBerry 10, and with Android support added in 4.3 — Jelly Bean. Here’s your chance to get acquainted which what the specification brings to the table. The source material (which we’ll talk about below) provides a ton of background. But if you want a succinct overview check out [Gervasi’s] summary of Bluetooth Low Energy.

We won’t republish the technical details here as both articles do a great job of covering those. Here’s what you should take away from BLE: It’s meant for use with devices running off of a tiny power source. The one outlined in both articles is a coin-cell. But we prefer to think of the future that is energy harvesting. Peak current is limited to 15 mA. This does limit the throughput, but think sensors, not Bluetooth headsets. You just don’t need to push all that much data from these devices. A cleverly designed energy harvesting circuit should be able to implement BLE devices with no battery whatsoever.

We did mention a deeper exploration of the standard. The image above comes from this BLE Primer for Developers. Add it to your weekend reading.

[via Reddit]

Wheelchair Hack Lets Two-year-old Explore On His Own

August 29, 2013 by Mike Szczys 37 Comments

[Shea’s] son [Alejandro] was born with Spinal Muscular Atrophy which limits his ability to move. The ability to explore one’s environment as a toddler is really important to development so [Shea] and his wife have been looking into assistive technology. Their health insurance paid for a medical stroller when he was nine-months old and has told the family they need to wait five years for a powered wheelchair. Rather than wait, [Shea] took it upon himself to hack a wheelchair his son could control.

He found a used adult-sized motorized wheelchair on eBay for about $800. Not cheap, but way more affordable than a brand new unit. This type of chair is made to be controlled with a joystick, an option not available to his son at this point. Foot control was an option if he could figure out how to build an interface.

After unsuccessfully trying to repair a broken digital kitchen scale [Shea] was inspired to reuse the sensors as pedal inputs. [Alejandro] has limited foot strength and the sensitive strain gauges are perfect for picking it up. Above you can see the sandal-based interface he built. The two feet working together affect steering as well as forward and reverse. The pedal system is connected to the wheelchair using a Digital to Analog converter chip to stand-in for the original analog joystick. After the break we’ve embedded a video of [Alejandro] exploring the outdoors in the finished chair.

In this case it’s fortunate that [Shea] has the skills to build something like this for his son. We hope this will inspire you to donate your time an know-how to help those in your own community who are in a similar situation. This really takes the concept of The Controller Project to the next level.

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Laser Cut Arc Reactor Replica

August 29, 2013 by Mike Szczys 31 Comments

laser-cut-arc-reactor

We’re starting to become a repository for Arc Reactor replica projects. The one shown above uses mostly laser cut components. We missed it back in May when [Valentin Ameres] tipped us off the first time. But he sent it in again after seeing the 3D printed version earlier this month.

Our biggest gripe is that we don’t have our own laser cutter to try this out on. Everything has been cut from 2mm thick acrylic. The black, silver, and copper colored components were painted to achieve this look. Many of the clear parts also had a dot matrix etched into them to help with light diffusion.

Basic assembly just required the parts be glued together. The finishing touches include wire-wrapping the slots of the outer ring and adding LEDs and current limiting resistors.

The plans are not freely available, but the 3D printed version linked above doubles as a 123D tutorial. That should help get you up to speed designing your own if you are lucky enough to have time on laser cutter.

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