Midwest RepRap Festival, March 20-22nd

Right now there are two emails in my inbox inviting me to 3D printer conventions. If you’re not familiar with how these cons go, here’s a quick recap: a bunch of 3D printer manufacturers set up their booths the day before, put a printer behind an acrylic enclosure, start a very complex print, and come back the next day. This printer finally completes the print sometime Sunday afternoon, a bunch of people walk by the booths, and the entire venue is filled with enough morose faces as to be comparable to one of the higher circles of hell.

The Midwest RepRap Festival is not this con. It is, to the best of my knowledge, the only 3D printing convention that isn’t a trade show. It’s a blast, it’s March 20th through the 22nd, and we’re going to be there.

This will be our second expedition to the MRRF. Last year we saw 3D printed resin molds, and a strange Core XZ printer from [Nicholas Seward], the mind that brought you the odd Reprap Wally and Simpson. The most interesting man in the universe was there with a Smoothieboard. There were talks on 3D Bioprinting by [Jordan Miller] from Rice University, and everyone ate 3D printed waffles. If you’re looking for the possibilities 3D printing offers, this is the con to go to. If you’re looking for people to sell you stuff, look elsewhere.

This event is organized by the folks at SeeMeCNC, and it will be held on their home turf of Goshen, Indiana. Yes, you will be passing Amish buggies on the way to the event. Even though the MRRF is being held in the middle of nowhere, it was absolutely shocking how many people turned up last year and how good the con was. To put this in perspective, I’m driving nine hours to MRRF, and going to Maker Faire NYC takes me four hours. If I had to choose one 3D printing event to go to, this would be the one. That’s not just because I’m told there will be a t-shirt cannon at MRRF.

The event is free and open to everybody. You can just show up, although it would be a good idea to register. You’ll see the World’s Largest 3D Printed Trash Can. Yes, I’m serious. Call Guinness.

EVA: What’s on Telly for the Visually Impaired

[chewabledrapery] has certainly used his Raspberry Pi for good. His girlfriend’s grandfather is growing more visually impaired as time goes on. He likes to watch telly, but has trouble reading the on-screen information about the channel and programming. To that end, [chewabledrapery] has built an electronic voice assistant called EVA, who fetches the telly schedule from a web service and reads it aloud in her lovely voice that comes courtesy of Google Translate’s TTS function.

Under EVA’s hood is a Raspberry Pi. A USB hub powers the Pi and holds a small USB soundcard, a Wi-Fi dongle, and a USB daughterboard that the controller plugs into. The daughterboard is from a USB keyboard, which makes another appearance in the awesome controller. It’s made of a joystick and two arcade buttons that use the USB keyboard’s controller to interact with Python scripts.

[chewabledrapery]’s scripts make formatted requests to a web service called atlas, which returns JSON objects with the TV schedule and content descriptions. EVA then turns to Google Translate, speaking the formatted text through a small amplifier and salvaged PC speaker. In order to minimize the number of web calls, some of EVA’s frequent musings are stored locally. A full tour of EVA is after the break.

We love to see hacks that help people. Remember this RFID audio book reader?

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Design & Build Part 2: Multi-Band, Phasing SSB, and SDR

 

Amateur radio is the ultimate hacker’s hobby. You can design, build, and put on the air your own high power transceivers. And with this homemade gear you are able to reach out directly, not relying on any infrastructure whatsoever, to connect with people all over the world. It is a thrilling experience to communicate with that long distance station using equipment you created, where you know at that instant what every single transistor is doing as you key down the mic.

In a previous post I described how SSB radio equipment worked and provided an example of a single-band 20m SSB transceiver. In this post I will discuss a multi-band SSB transceiver, an entire homemade amateur station including amplifiers, and conclude with software defined radio (SDR) that you can make in one weekend.

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Arduino Zero Pro Soft Release?

There’s an updated product page for the Arduino Zero, now called the Arduino Zero Pro, up on Arduino.org, one of the two dueling “Arduinos”.

We first covered the Arduino Zero in May 2014, and shortly thereafter even got to see a development prototype in the flesh. Based an Atmel’s ARM Cortex-M0+ chip, it’s built on a faster processor than the AVR Arduini, and it includes Atmel’s Embedded Debugger which serves as a USB-to-serial channel and on-chip debugging peripheral. But so far all we’ve seen is the prototype.

Now, there’s schematics and Eagle files available that are dated January 7, 2015. The Arduino.org site says that the Zero Pro is “Available now!” but we couldn’t see any in stock yet at any of our favorite online electronics distributors. Maybe we’re looking in the wrong places (unlikely) or maybe it’s just a matter of time.

Anyway, two things struck us in our casual perusal of the new Zero Pro info.

First of all, compared to (pictures of) the prototype versions, there’s more and larger decoupling capacitors scattered all over the board, from the power supply to the Embedded Debugger chip, to a really beefy 4.7uF tantalum capacitor buffering the analog reference voltage level. This suggests there’s been some real-world testing and a shakedown of some of the prototype’s design bugs. That’s all good, and we hope it’s a sign that it’s really coming to market soon.

Secondly, given the ongoing trademark dispute, even the annotations to the schematic for the Zero Pro become interesting. On opening up either the PDF schematic (PDF, naturally) or any of the Eagle files, there’s the usual “Do not finalize a design with this information” boilerplate. But where it used to read “Arduino is a registered trademark. Use of the ARDUINO name must be compliant with http://www.arduino.cc/en/Main/Policy ” it now reads:

“Arduino” name and logo are trademarks registered by Arduino S.r.l. in Italy, in the European Union and in other countries of the world.

(After noticing this change, we went back and compared the “rev3″ Uno schematics PDF on arduino.cc to the “rev3E” schematics on arduino.org. Yup, same change in the legal notice.)

We’re not lawyers, but one of the “other countries of the world” that’s conspicuously missing from the claim is the U.S. of A. where Arduino LLC presumably holds the trademark. We’re still trying to make sense of all this, but it’s funny to see the legal battle playing itself out in annotations of Eagle schematics, no?

Stay tuned for more coverage of the Arduino vs Arduino legal battle and, of course, reviews of new hardware as it comes out.

And thanks [Marc] for the tip to the new board release.

Face Recognition For Your Next Con

[jwcrawley] is busy planning for the Makevention coming up in Bloomington, Indiana in late August. One problem when working any con is manning the door; it’s a good idea to know how many people are there, and you can’t double count people. Previously, the volunteers used dead trees to estimate how many people have turned up. This year they might go with a more technological solution: face recognition and tracking.

The project is called uWho, and it uses the faceRecognizer class in OpenCV. The purpose of the entire project is to identify who someone is from previous frames. If your face is unknown to the program, your likeness – rather, a few points of data – are added to the database of faces. It’s simple, and according to [jwcrawley], it works.

While this is technically the best way to count how many unique people show up to Makevention, there will be some discussions to see if this solution is appropriate. The program only saves unique data from a face locally, and does nothing online. It’s less evil than whatever Facebook does, but there are obvious privacy implications here.

Link to the Makevention.

Nixie inspired 7 segment display

The supply of Nixie tubes from east European stock piles is still enough to keep their prices down. But once those start dwindling, prices will move north. Besides, if you want to use them, you need to work with high voltage supplies and worry about not getting zapped while trying to debug a circuit. [FilleK] had some time to spare and decided to build a cheaper substitute for a real nixie tube using a regular 7 segment LED display.

We have already seen this hack before, in the Arduino-based ENIGMA replica. But [FilleK] improved on that by adding an extra LED to simulate the radiant glow typical of Nixie tubes. His project log describes the fairly straightforward process using parts that can be found easily. A piece of plastic, painted in a shade of copper and fixed around the 7 segment display, acts as a nice baffle to contain and reflect the ambient glow of the back-light LED. A nice improvement would be to add a random flicker to the background LED. Maybe add an Octal socket (the decimal point had to be nixed though!), and cap it in a proper glass tube. If you’d rather work with the real McCoy, check out our archives.

Hard Drive… Speakers?

Speakers really aren’t that complex to make. In fact, if you’re clever about it, you can make a speaker out of just about anything. [Afroman] is kicking it old school with a hack he first did back in 2001, but now, in video form: Make your own HDD Speaker!

All you need is an old hard drive you don’t care about anymore, a bit of flexible wire, and an externally powered amplifier (no your cellphone will not work!). If you don’t have an amp, [Afroman] even has a tutorial so you can build your own Class D Amplifier on a breadboard!

First off you’ll need to crack open the HDD enclosure. You might need a torx or hex key to get past the manufacturer’s “safety screws” though. Once it’s open you’ll need to locate the hard drive head — this is the small metal arm that looks kind of like a record player tone arm. It’s actually controlled by a coil, you know, just like a speaker…

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