Skills

351 Articles

Video Streaming Like Your Raspberry Pi Depended On It

September 12, 2017 by 23 Comments

The Raspberry Pi is an incredibly versatile computing platform, particularly when it comes to embedded applications. They’re used in all kinds of security and monitoring projects to take still shots over time, or record video footage for later review. It’s remarkably easy to do, and there’s a wide variety of tools available to get the job done.

However, if you need live video with as little latency as possible, things get more difficult. I was building a remotely controlled vehicle that uses the cellular data network for communication. Minimizing latency was key to making the vehicle easy to drive. Thus I set sail for the nearest search engine and begun researching my problem.

My first approach to the challenge was the venerable VLC Media Player. Initial experiments were sadly fraught with issues. Getting the software to recognize the webcam plugged into my Pi Zero took forever, and when I did get eventually get the stream up and running, it was far too laggy to be useful. Streaming over WiFi and waving my hands in front of the camera showed I had a delay of at least two or three seconds. While I could have possibly optimized it further, I decided to move on and try to find something a little more lightweight.

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How To Do PCB Art In Eagle

August 30, 2017 by 17 Comments

Last month I had the pleasure of creating a new piece of hardware for Tindie. [Jasmine], the queen bee of Tindie, and I designed, developed, and kitted three hundred Tindie badges in ten days leading up to DEF CON. The badges were a complete success, they introduced soldering to a lot of people, and were loved by all.

This badge was such a rousing success, it’s now official Tindie swag. We’ll be handing out a few of these blinky badges at upcoming events. But as of right now we’ve already handed out our entire stock, that means we need to build more. The second run meant ordering a thousand PCBs.

We could just do another run, and order a few more PCBs from the Gerbers I’ve already designed. I’m not really happy with the first version of this badge, though, and this is an opportunity to improve my design. This also gives me an opportunity to demonstrate my workflow for creating artistic boards in Eagle.

Effectively, what I’ll be demonstrating here is the creation of the Benchoff Nickel. A few months ago, [Andrew Sowa] took a portrait of yours truly, changed the colors to what is available on a normal OSHPark PCB, and turned that into different layers in KiCad. There are a few differences here. Firstly, I’ll be using a blue solder mask, although the same technique can be applied to green, red, yellow, white, or black soldermask. Secondly, this is Eagle, and I’m going to do the majority of the work with a BMP import. This is the fast and easy way to do things; if you want a KiCad tutorial, check out [Andrew]’s work, or my overly-involved multiple silkscreen process for KiCad. I don’t recommend this overly-involved process if you can help it. It took 20 hours to do the art for my previous project in KiCad, and I estimate it would have taken two in Eagle.

With that said, here’s the easy, cheap, and fast way of doing artistic boards in Eagle.

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Modular Storage With Peanut Butter And Lasers

August 23, 2017 by 22 Comments

I have storage on the mind, and it comes from two facts in my life:

First, I have tons of stuff in my workshop, far too much for the amount of space I have. A lot of this material is much easier to use if it’s well-organized. Think electronics, robotics, building sets. Modular parts that need to go together a certain way for them to be useful. It is imperative, therefore, that I come up with some sort of organization system to keep the chaos in check.

Second, my favorite tool is the laser cutter, born from my love for building vector designs. I can do art on the computer and have it manufactured in front of my eyes, and share my designs with someone else who can remix it into something even cooler.

So with those two facts in mind, I set about creating a modular storage system in Inkscape and cutting out the design from pine boards using a laser cutter. Let us go on a journey through my thought process:

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Lasering Axonometric Fonts

August 18, 2017 by 15 Comments

I am something of an Inkscape fan. If you’re not familiar with the application, it’s like an Open Source version of Adobe Illustrator. Back when I was a production artist I’d been an Illustrator master ninja but it’s been four years and my skills are rusty. Plus, Inkscape is just enough different in terms of menus and capabilities that I had a hard time adapting.

So I created some wooden lettering with the help of Inkscape and a laser cutter, and I’m going to show you how I did it. If you’re interested in following along with this project, you can find it on Hackaday.io.

While playing around with Inkscape, I noticed you can create a variety of grids, including axonometric grids. This term refers to the horizon lines in an orthographic projection. In other words, it helps make things look 3D by providing perspective lines.

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Testing Distance Sensors

August 11, 2017 by 40 Comments

I’m working on a project involving the need to precisely move a tool based on the measured distance to an object. Okay, yeah, it’s a CNC mill. Anyway, I’d heard of time of fight sensors and decided to get one to test out, but also to be thorough I wanted to include other distance sensors as well: a Sharp digital distance sensor as well as a more sophisticated proximity/light sensor. I plugged them all into a breadboard and ran them through their paces, using a frame built from aluminum beams as a way of holding the target materials at a specific height.

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Getting Started With Blinking Lights On Old Iron

August 10, 2017 by 29 Comments

If you ever go to a computer history museum, you’ll be struck by how bland most modern computers look. Prior to 1980 computers had lights and switches, and sometimes dials and meters. Some had switchboard-like wiring panels and some even had oscilloscope-like displays. There’s something about a machine with all those switches and lights and displays that gets your hacker juices flowing. Have you ever wanted to get started in retrocomputing? Is it difficult? Do you need a lot of money? That depends on what your goals are.

There are at least three ways you can go about participating in retrocomputing: You can pony up the money to buy actual antique computers, you can build or buy old computers recreated with anywhere from zero to one hundred percent of period-authentic components, or you can experiment with emulators that run on a modern computer. As a hybrid of the second and third option there are also emulations in FPGAs.

You can see that the first option can be very expensive and you will probably have to develop a lot of repair and restoration skills. Watching [Mattis Lind] twiddle the bits on an actual PDP-8 in the clip above is great, but you’ll need to work up to it. The two techniques which get you going without the original hardware don’t have to break the bank or even cost anything presuming you already have a PC.

Although some sneer at emulation, for some machines it is almost the only way to go. You couldn’t buy the original EDSAC, for example. It is also a good way to get started without a lot of expense or risk. But regardless of how you do it, there’s one thing in common: you have to know how to operate the thing.

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Hack Your Memory

August 4, 2017 by 78 Comments

Imagine a fire hydrant being lifted high into the air by a large helium balloon. It goes higher and higher, but suddenly gas starts to leak out of the nozzle, which makes it sound like it’s trying to talk… but with a distinct lisp. A colorful bumblebee then lands on the balloon, licks it, and says “really yum!”  Then the bee takes out its stinger and bores on to the balloon. It pops, causing the fire hydrant to come crashing down. It smashes into a military jeep causing a massive explosion… as if it had been destroyed by a car bomb. Fortunately, the owner of the jeep, a general, was out on his rowing boat at the time. He likes to row his boat at night, and is known as the “night-rowing general” around the base. He was rowing with a bit more exertion than usual, and had to don an oxygen mask to help him breath. But the mask was full of fluoride, which turned his teeth bright neon colors.

You’re probably wondering what the hell you just read. Maybe you’re thinking the author had a stroke. Has the site been hacked? Maybe it’s a prank? What if I told you that you’ve just memorized the first 10 elements of the periodic table.

The Night-Rowing-General via Memorize Academy
  • Fire hydrant – Hydrogen
  • Helium balloon – Helium
  • Lisp – Lithium
  • Bee says “really yum” – Beryllium
  • Bee “Bores on” – Boron
  • Car bomb – Carbon
  • The night-rowing-general – Nitrogen
  • Oxygen mask – Oxygen
  • Fluoride – Florine
  • Neon teeth – Neon

Much of your memory is stored in the form of associations. Encoding things you need to remember into a silly story takes advantage of this fact. The memory of a ‘night-rowing-general’ is already in your head. You can see him in the theater of your mind… rowing his boat under a black sky… the silver stars on his green hat reflecting the moonlight. Associating this visual representation of the night-rowing-general with the term ‘Nitrogen’ is very easy for your brain to do.

You’re probably already familiar with this type of learning. Does “Bad Boys Run Over Yellow Gardenias Behind Victory Garden Walls” ring a bell?  It’s nothing new. In fact, storing memories in the form of mental images was the preferred memorization method of the scholars in ancient times. Today, it has allowed people to perform staggering feats of memorization. Want to know how [Akira Haraguchi] was able to memorize 111,700 digits of Pi?

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