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Hackaday Links: September 4, 2016

Nozzle socks! Just keep saying, ‘nozzle socks’ until the semantic satiation undoes any semblance of sanity. E3D, makers of the world’s finest 3D printer hotends have released silicone nozzle covers that prevent caramelized plastic gunking up your hot end. Nozzle socks.

Let’s talk guitar pedals. If you’ve ever built your own guitar pedal, you probably stuffed it inside a Hammond enclosure. There’s more to guitar pedal enclosures than custom-painted electronic boxes, and arguably the best enclosures are the ‘Boss’ style – a metal cover over the switch that can be removed to access the battery independently of the circuit. Now you can buy this type of enclosure. [Rixen] is producing blank die-cast aluminum pedals that look so much better than the standard Hammond enclosure.

The Antonov AN-225 is the largest and heaviest airplane in the world. Only one was built. For the last thirty years, a second airframe, about 70% complete, has sat in a field or hangar in the Ukraine, waiting for someone to put it into service. After numerous false starts over the past decade or so, the second AN-225 is finally being built.

The Hackaday Retro edition is our version of Hackaday optimized for embedded devices. When someone gets some old hardware on that vast World Wide Web and manages to pull up the retro edition, we like to celebrate. [Michael] recently got his old Amiga 1200 online and managed to find the software and hardware to get this machine on the net. Inside the A1200 is a 4GB CompactFlash, an ACA 1232 accelerator card with 128MB of RAM and a 33MHz 030. The network is handled by a Linksys EC2T card, and the software is KS3.0, WB3.1, MiamiDX IP stack IBrowse 2.4, and a bunch of 3rd party libs he can’t remember. Here’s a pic.

On a related note, I haven’t touched the Hackaday Retro Edition in years. Right now, it’s just a script running every five minutes that assembles five random posts from the first 15,000 Hackaday posts since the beginning of time. The retro edition does what I want it to do, but I’m wondering if it can be better. If you have an idea of how to improve the Retro Edition, leave a note in the comments.

Hacklet 123 – Watches

Time and tide wait for no man. Chaucer may be right, but a man (or woman) wearing a watch can get ahead of time before it sneaks up on them. People aren’t ever satisfied with just the time though. They want the date, the phase of the moon. [Woz] summed it up pretty well when he said “I want the entire smartphone, the entire Internet, on my wrist”.   Hackers love watches too, which means there are plenty of watch projects out there. Some of them even tell time. This week we’re looking at some of the best watch projects on Hackaday.io!

chronioWe start with [Max.K] and Chronio. You might think Chronio looks a bit like the Pebble Time, and you’d be right! [Max] based his design heavily on Pebble’s case design. Pebble even has their CAD files on GitHub, which helped [Max] with his modified, 3D printed version. Chronio is Arduino based, using an ATmega328p microcontroller with the Arduino bootloader. The display is Sharp’s 96×96 pixel Memory LCD. A DS3231 keeps the time accurate, and provides a free temperature sensor. The entire watch is powered by a CR2025 battery. Running a 20uA sleep current, [Max] estimates this watch will last about 6 months on a single battery.

neopixel-pocketNext we have [Joshua Snyder] and Neopixel pocket watch. Who said a watch has to go on your wrist? [Joshua] brings some steampunk style to the party. His watch uses an Adafruit 12 NeoPixel ring to tell time. Red, blue, and green LEDS represent the hour, minute and second hands. The watch is controlled by an ESP8266. The time is set via WiFi. Between the LEDs and the power-hungry ESP8266, this isn’t exactly a low-power design. A 150mAh LiPo battery should keep things running for a few hours though. That’s more than enough time to make a splash at the next hackerspace event.

pi-watchNext up is [ipaq3115] and The Pi Watch. Round smartwatches have created a market for round LCD screens. These screens have started to trickle down into the hacker/maker market. [ipaq3115] got his hands on one, and had to design something cool with it. The Pi Watch isn’t powered by a Raspberry Pi, but a Teensy 3.1. [ipaq3115] included the Freescale/NXP Kinetis processor and MINI54 bootloader chip on his own custom board. He used the Teensy’s analog inputs to create his own 10 element capacitive touch ring. This watch even has a LSM303  magnetometer/accelerometer. All this power comes at a cost though. It takes a 480 mAh LiPo battery to keep The Pi Watch Ticking.

vikasFinally we have [Vikas V] and ScrolLED watch. Who says a watch has to have an LCD? [Vikas V] wanted a scrolling LED display on his wrist, so he built his own. An Atmel ATmega88V-10AU controls a 16×5 charlieplexed LED array. [Vikas] included a character font with many of the ASCII symbols in flash, so this watch can display messages. Power comes from a CR2032 watch battery in a custom PCB mounted holder. [Vikas] biggest issue so far has been light leaks from LED to LED. He’s considering mounting the array on the bottom of the watch. Shining the LEDs up through holes in the PCB would definitely help with the light leakage.

If you want to see more watch projects, check out our new watch projects list. Notice a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Books You Should Read: Engineer To Win By Carroll Smith

One problem with engineering education today is a lack of experimental teaching. Oh sure you may have a project or two, but it’s not the focus of the program because it’s hard to standardize a test around. Typically sections of the field are taught in a highly focused theoretical course by a professor or graduate student with a specialization in that section. Because classes treat individual subject areas, it’s entirely possible to get a really good understanding of two pieces of the same puzzle, but never realize that they fit together to make a picture. It’s only when a freshly minted engineer gets out into the real world that they start to make the connections between seemingly disparate fields of knowledge.

This is why Carroll Smith’s book “Engineer to Win” is so good. He spent a lifetime as a practicing engineer in a field where a small failure could mean the death of a friend. So when he set out to write a book, he wrote a book that related everything needed to properly conceptualize and solve the mechanical engineering problems in his field.

One warning though; the book is not for the faint of heart. If you want to learn something difficult well, then this is book for you. Carroll skips the comforting analogies and gives the information exactly. It can get a little dense, but he makes the assumption that the reader is there to learn and, most importantly, understand. This takes work.

2016-08-01_02h06_34For example, you can’t really understand why a rolled bolt is stronger than a bolt cut on a screw machine until you understand how metal works on a crystalline level. The same goes for metal fatigue, brittle fractures, ductile failures, and all the maladies that metal can suffer. The difference between an engineer and a technician is this deep understanding. Otherwise the equations learned are just parts in a toolbox and not paint on an artist’s palette.

This is why the first half of the book is dominated by all things metallurgical. The book starts with the simple abstractions of the crystalline structures of metal. Unlike my materials class in university, it maintains a practical bend to the presentation of the information throughout the whole process. For example, it moves on to what all this practically means for metals undergoing stresses and failures before it launches into a (short) digression on how metals are made and their history.

However, if racecar plumbing is your thing his treastise, "Carroll Smith's Nuts, Bolts, Fasteners and Plumbing Handbook" is also fantastic.
However, if racecar plumbing and fasteners are kinda your thing, “Carroll Smith’s Nuts, Bolts, Fasteners and Plumbing Handbook” is also a fantastic read.

This first half of the book touches on non-ferrous metals and their proper use as well. After that comes some of the best explanations of metal fatigue, fasteners, and metal bonding I’ve ever read. When the failure of a joint causes a mechanism to fail in a toaster that’s one thing, but when it fails in a racecar people get hurt. Carroll is very exacting in what constitutes a forgivable oversight in engineering, and what does not.

Once the book has finished conveying a working understanding of metals and fasteners it seems to fracture into a pot-luck of different racecar-related topics. During my first reading of the book I resisted this strange turn of events. For example, I didn’t really want to read about racecar plumbing in the eighties, or what kind of springs and aerofoils Carroll likes. However, when I reread those sections in a more focused manner, I realized that many of them were teaching the practical application of the knowledge learned in the previous chapters. How does the metal make a good spring? Why is one kind of plumbing better than another?

Importantly, the anecdotes at the end of the book impart an understanding of the importance of professionalism in engineering. What is the true responsibility of an engineer? He teaches not to take the trust others place in your skills for granted. He teaches to trust in the skills of others. The book teaches humility as an engineer. He shows the kind of person one can become after a lifetime of earnest study in their craft.

Thanks to reader, [Dielectric], for recommending the book to me. Also, from the bit of research I’ve done, the older motorworks edition is generally considered to have better quality reproductions of the diagrams than the newer printings of the book.

How To Use Docker To Cross Compile For Raspberry Pi (and More)

It used to be tedious to set up a cross compile environment. Sure you can compile on the Raspberry Pi itself, but sometimes you want to use your big computer — and you can use it when your Pi is not on hand like when on an airplane with a laptop. It can be tricky to set up a cross compiler for any build tools, but if you go through one simple step, it becomes super easy regardless of what your real computer looks like. That one step is to install Docker.

Docker is available for Linux, Windows, and Mac OS. It allows developers to build images that are essentially preconfigured Linux environments that run some service. Like a virtual machine, these images can run together without interfering with each other. Unlike a virtual machine, Docker containers (the running software) are lightweight because they share the same underlying kernel and hardware of the computer.

The reality is, setting up the Raspberry Pi build environment isn’t any easier. It is just that with Docker, someone else has already done the work for you and you can automatically grab their setup and keep it up to date. If you are already running Linux, your package manager probably makes the process pretty easy too (see [Rud Merriam’s] post on that process). However, the nice thing about the images is it is a complete isolated environment that can move from machine to machine and from platform to platform (the Windows and Mac platforms use a variety of techniques to run the Linux software, but it is done transparently).

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Circuit Design? Spread The Joy

Accountants and MBAs use spreadsheets to play “what if” scenarios with business and financial data. Can you do the same thing with electronic circuits? The answer–perhaps not surprisingly–is yes.

Consider this simple common emitter amplifier (I modeled it in PartSim, if you’d like to open it):

In this particular case, there are several key design parameters. The beta of the transistor (current gain) is 220. The amplifier has an overall voltage gain of about 3 (30/10). I say about, because unless the transistor is ideal, it won’t be quite that. The supply voltage (Vcc) is 12 volts and I wanted the collector voltage (VC) to idle at 6V to allow the maximum possible positive and negative swing. I wanted the collector current (IC) to be 200mA.

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Four Of Our Favorite Hardware Talks

The Hackaday SuperConference is the greatest gathering of hardware hackers on the planet. Last year at the SuperCon, we saw talks on building systems from scratch, creating new and interesting uses for technology, and bringing those electronic bits to market. What are we talking about? Here are four of the best talks from last year’s Hackaday SuperConference:

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Shell Game

A lot of us spend a lot of time switching between Windows and Linux. Now that platforms like the Raspberry Pi are popular, that number is probably increasing every day. While I run Linux on nearly everything I own (with the exception of a laptop), my work computers mostly run Windows. The laptop is on Windows, too, because I got tired of trying to get all the fancy rotation sensors and pen features working properly under Linux.

What I hate most about Windows is how hard is it to see what’s going on under the hood. My HP laptop works with a cheap Dell active stylus. Sort of. It is great except around the screen edges where it goes wild. Calibration never works. On Linux, I could drill down to the lowest levels of the OS if I were so inclined. With Windows, it is just tough.

War is Shell

One place where Linux always used to have an advantage over DOS and Windows was the shell. There are lots of variations available under Linux, but bash seems to be the current pick for most people. If you want more power, you can move to some alternatives, but even bash is pretty powerful if you learn how to use it and have the right external programs (if you don’t believe it, check out this web server).

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