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Hackaday Links: September 3, 2017

September 3, 2017 by 35 Comments

The TI-83, TI-84, and TI-86 have been the standard graphing calculators in classrooms for two decades. This is the subject of an xkcd. Now, hopefully, there’s a contender for the throne. Numworks is a graphing calculator that looks like it was designed in at least 2006 (so very modern), and apparently, there’s a huge community behind it.

Juicero is shutting down. No one could have seen this one coming. The Juicero was a $700 press that turned proprietary, DRM’ed juice packs into juice and garbage. It was exquisitely engineered, but it turns out very few people want to spend thousands of dollars per year on DRM’ed juice. Oh, since the Juicero phones home, those $700 presses probably won’t work in the future.

Are you in the Bay area? Do you need test equipment? There’s a gigantic auction happening somewhere around San Jose. [Dave] tipped everyone off to this one, and this auction is pretty freakin’ spectacular. Spectrum analyzers, signal gens, a ‘mega zoom’ oscilloscope, and 4-channel, 500 MHz scopes for $50. There are a thousand lots in this auction. It’s nuts.

Everybody loves PCB art, and [Uri] has a guide for designing custom, functional electronic circuit boards. The toolchain used in this guide is Inkscape and KiCad, with blinky hearts, blinky pandas, and other blinky PCBs.

This one is a little out there even for us. Here’s how you build your own AA batteries. It’s a dozen #10 copper washers, a dozen or so #10 zinc washers, some cardboard, vinegar, salt, and some heat shrink tubing. The assembly of this battery is exactly what you would expect, and yes, it does work. Here’s the thing, though: The very crude tests suggest these batteries have a capacity of about 800-1000 mAh, which is far more than we would expect. Who has a programmable load and wants to do a few experiments? Also, these batteries are ‘rechargeable’ by taking them apart, sanding the crud off each washer, and adding new electrolyte.

[Jan] has made a name for himself stuffing synthesizers into tiny little microcontrollers. The latest project is the Infinity37, a polyphonic synth with MIDI, envelopes, and a whole bunch of cool stuff. Check out the video.

[rctestflight] is building a solar powered aircraft. It’s has a beautiful wing studded with solar panels. The latest flight was four hours, long enough to make piloting a plane through some FatSharks extremely tedious. Future developments will probably include a MPPT charging solution, and probably an autopilot.

Hackaday Prize Entry: Remote Control By Head Gestures

September 3, 2017 by 8 Comments

Some people may think they’re having a bad day when they can’t find the TV remote. Yet there are some people who can’t even hold a remote, let alone root around in the couch cushions where the remote inevitably winds up. This entry in the Assistive Technologies phase of the 2017 Hackaday Prize seeks to help such folks, with a universal remote triggered by head gestures.

Mobility impairments can range from fine motor control issues to quadriplegia, and people who suffer from them are often cut off from technology by the inability to operate devices. [Cassio Batista] concentrated on controlling a TV for his project, but it’s easy to see how his method could interface with other IR remotes to achieve control over everything from alarm systems to windows and drapes. His open-source project uses a web cam to watch a user’s head gestures, and OpenCV running on a CHIP SBC looks for motion in the pitch, yaw, and roll axes to control volume, channel, and power. An Arduino takes care the IR commands to the TV. The prototype works well in the video below; with the power of OpenCV we can imagine mouth gestures and even eye blinks adding to the controller’s repertoire.

The Assistive Tech phase wraps up tomorrow, so be sure to get your entries in. You’ll have some stiff competition, like this robotic exoskeleton. But don’t let that discourage you.

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Have Alexa Open Your Garage Door

September 3, 2017 by 17 Comments

[yoyotechKnows] built an Alexa-controlled garage door opener after his Liftmaster stopped working. Now all he has to do is holler at his mobile phone and he can raise and lower his garage doors at will.

His project is based around a Photon WiFi kit, with a pair of LCC 120 digital relays triggering the two doors, reed switches, and a serial-equipped LCD to display door status, with Alexa, IFTTT, and OpenHab to process the commands. You can find his code in the project writeup.

Currently he has a LCD display informing him of the status of each door, hot glued a reed switch to keep track of whether each one is closed. This might seem a little bit extraneous since he can also just look at the doors from within the garage. However, he’s thinking about putting the display inside his house. But couldn’t he just ask Alexa?

We love us our home automation here at Hackaday, with everything from swimming pools to chicken coops rigged for app control and datalogging.

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Make Cars Safer By Making Them Softer

September 3, 2017 by 78 Comments

Would making autonomous vehicles softer make them safer?

Alphabet’s self-driving car offshoot, Waymo, feels that may be the case as they were recently granted a patent for vehicles that soften on impact. Sensors would identify an impending collision and adjust ‘tension members’ on the vehicle’s exterior to cushion the blow. These ‘members’ would be corrugated sections or moving panels that absorb the impact alongside the crumpling effect of the vehicle, making adjustments based on the type of obstacle the vehicle is about to strike.

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How To Select Just About Any Electronic Part

September 3, 2017 by 14 Comments

Sometimes you see an excellent post somewhere else on the web, and then discover that it is one of a series of similarly good posts that you completely missed when they were published. If you are a Hackaday scribe you are left wondering how you managed to pass them by, and then why on earth you didn’t think of writing them yourself.

Such is the case with [Sanket Gupta]’s excellent series for Octopart, of posts titled “How to select a…” and then a class of component. It was the latest, “How to select a voltage regulator” that caught our eye first, but then we found the previous installments dealing with capacitors, resistors, inductors, connectors, IC packages and MCUs. Each one provides a basic primer for the engineer, in terms of both parts selection based on capability and on suitability for manufacturing, and while you may think that only an inexperienced reader might find benefit in such pieces the reality is that everybody can learn something.

So if you are involved in choosing electronic parts, no matter at what level, take a look at this series. If you know everything [Sanket] has to say then we congratulate you on your mastery of the field, however we think most readers will find them to be an interesting and useful resource.

Header image: Kae [Public domain].

Poetry In Motion With A Sand-Dispensing Dot Matrix Printer

September 3, 2017 by 12 Comments

Hackaday gets results! Reader [John] saw our recent Fail of the Week post about a “sand matrix printer” and decided to share his own version, a sand-dispensing dot matrix printer he built last year.

Granted, [John]’s version is almost the exact opposite of [Vjie Miller]’s failed build, which sought to make depressions in the sand to print characters. [John]’s Sandscript takes a hopper full of dry, clean sand and dispenses small piles from six small servo-controlled nozzles. The hopper is mounted on a wheeled frame, and an optical encoder on one wheel senses forward motion to determine when to open each nozzle. As [John] slowly walks behind and to the side of the cart, a line of verse is slowly drizzled out onto the pavement. See it in action in the video below.

More performance art piece than anything else, we can see how this would be really engaging, with people following along like kids after the [Pied Piper], waiting to find out what the full message is. There’s probably a statement in there about the impermanence of art and the fleeting nature of existence, but we just think it’s a really cool build.

We’ve featured other sand writers before, like this high-resolution draw bot that also dispenses sandy verses, or this literal beach-combing art bot. Guess there’s just something about sand that inspires artists and hackers alike.

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Tracing A Scene An Old-Fashioned Way

September 2, 2017 by 23 Comments

Taking a picture is as simple as tapping a screen. Drawing a memorable scene, even when it’s directly in front of you, is a different skill entirely. So trace it! Well, that’s kind of hard to do without appropriate preparation.

[bobsteaman]’s method is to first whip up a pantograph — it tested well with a felt marker on the end. Next, he built a camera obscura into a small wood box with a matte plexiglass top, which didn’t work quite so well. A magnifying glass above the camera’s pinhole aperture helped, but arduous testing was needed to ensure it was set at perfect position for a clear image. The matte plexiglass was also thrown out and, after some experimentation, replaced with a sheet of semi-transparent baking paper sandwiched between two pieces of clear plexiglass. The result is hard to argue with.

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