Automatic Resistance: Resistors Controlled by the Environment

Resistors are one of the fundamental components used in electronic circuits. They do one thing: resist the flow of electrical current. There is more than one way to skin a cat, and there is more than one way for a resistor to work. In previous articles I talked about fixed value resistors as well as variable resistors.

There is one other major group of variable resistors which I didn’t get into: resistors which change value without human intervention. These change by environmental means: temperature, voltage, light, magnetic fields and physical strain. They’re commonly used for automation and without them our lives would be very different.

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A Brief History Of ‘Drone’

In the early 1930s, Reginald Denny, an English actor living in Los Angeles, stumbled upon a young boy flying a rubber band-powered airplane. After attempting to help the boy by adjusting the rubber and control surfaces, the plane spun into the ground. Denny promised he would build another plane for the boy, and wrote to a New York model manufacturer for a kit. This first model airplane kit grew into his own hobby shop on Hollywood Boulevard, frequented by Jimmy Stewart and Henry Fonda.

The business blossomed into Radioplane Co. Inc., where Denny designed and built the first remote controlled military aircraft used by the United States. In 1944, Captain Ronald Reagan of the Army Air Forces’ Motion Picture unit wanted some film of these new flying targets and sent photographer David Conover to the Radioplane factory at the Van Nuys airport. There, Conover met Norma Jeane Dougherty and convinced her to go into modeling. She would later be known as Marilyn Monroe. The nexus of all American culture from 1930 to 1960 was a hobby shop that smelled of balsa sawdust and airplane glue. That hobby shop is now a 7-Eleven just off the 101 freeway.

Science historian James Burke had a TV wonderful show in the early 90s – Connections – where the previous paragraphs would be par for the course. Unfortunately, the timbre of public discourse has changed in the last twenty years and the worldwide revolution in communications allowing people to instantaneously exchange ideas has only led to people instantaneously exchanging opinions. The story of how the Dutch East India Company led to the rubber band led to Jimmy Stewart led to remote control led to Ronald Reagan led to Death of a Salesman has a modern fault: I’d have to use the word ‘drone’.

The word ‘propaganda’ only gained its negative connotation the late 1930s – it’s now ‘public relations’. The phrase ‘global warming’ doesn’t work with idiots in winter, so now it’s called ‘climate change’. Likewise, quadcopter pilots don’t want anyone to think their flying machine can rain hellfire missiles down on a neighborhood, so ‘drone’ is verboten. The preferred term is quadcopters, tricopters, multicopters, flying wings, fixed-wing remote-controlled vehicles, unmanned aerial systems, or toys.

I’m slightly annoyed by this and by the reminder I kindly get in my inbox every time I use the dreaded d-word. The etymology of the word ‘drone’ has nothing to do with spying, firing missiles into hospitals, or illegally killing American civilians. People like to argue, though, and I need something to point to when someone complains about my misuse of the word ‘drone’. Instead of an article on Hollywood starlets, the first remote control systems, and model aviation, you get an article on the etymology of a word. You have no one else to blame but yourself, Internet.

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Hackspace Websites And The Great Software Trap

Part of the job of a Hackaday writer involves seeking out new stories to write for your delectation and edification. Our tips line provides a fruitful fount of interesting things to write about, but we’d miss so much if we restricted ourselves to only writing up stories from that source. Each of us writers will therefore have a list of favourite places to keep an eye on and catch new stuff as it appears. News sites, blogs, videos, forums, that kind of thing. In my case I hope I’m not giving away too much to my colleagues when I say I keep an eye on the activities of as many hackspaces as I can.

So aside from picking up the occasional gem for these pages there is something else I gain that is of great personal interest as a director of my local hackspace. I see how a lot of other spaces approach the web, and can couple it to my behind-the-scenes view of doing the same thing here in our space. Along the way due to both experiences I’ve begun to despair slightly at the way our movement approaches the dissemination of information, the web, and software in general. So here follows a highly personal treatise on the subject that probably skirts the edge of outright ranting but within which I hope you’ll see parallels in your own spaces.

Before continuing it’s worth for a moment considering why a hackspace needs a public website. What is its purpose, who are its audience, and what information does it need to have?

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Preparing Your Product For The FCC

At some point you’ve decided that you’re going to sell your wireless product (or any product with a clock that operates above 8kHz) in the United States. Good luck! You’re going to have to go through the FCC to get listed on the FCC OET EAS (Office of Engineering and Technology, Equipment Authorization System). Well… maybe.

As with everything FCC related, it’s very complicated, there are TLAs and confusing terms everywhere, and it will take you a lot longer than you’d like to figure out what it means for you. Whether you suffer through this, breeze by without a hitch, or never plan to subject yourself to this process, the FCC dance is an entertaining story so let’s dive in!

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Resistance in Motion: What You Should Know About Variable Resistors

Adjusting the volume dial on a sound system, sensing your finger position on a touch screen, and knowing when someone’s in the car are just a few examples of where you encounter variable resistors in everyday life. The ability to change resistance means the ability to interact, and that’s why variable resistance devices are found in so many things.

The principles are the same, but there are so many ways to split a volt. Let’s take a look at what goes into rotary pots, rheostats, membrane potentiometers, resistive touchscreens, force sensitive resistors, as well as flex and stretch sensors.

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ESP32 Hands-On: Awesome Promise

The ESP32 is looking like an amazing chip, not the least for its price point. It combines WiFi and Bluetooth wireless capabilities with two CPU cores and a decent hardware peripheral set. There were modules in the wild for just under seven US dollars before they sold out, and they’re not going to get more expensive over time. Given the crazy success that Espressif had with the ESP8266, expectations are high.

And although they were just formally released ten days ago, we’ve had a couple in our hands for just about that long. It’s good to know hackers in high places — Hackaday Superfriend [Sprite_tm] works at Espressif and managed to get us a few modules, and has been great about answering our questions.

We’ve read all of the public documentation that’s out there, and spent a week writing our own “hello world” examples to confirm that things are working as they should, and root out the bugs wherever things aren’t. There’s a lot to love about these chips, but there are also many unknowns on the firmware front which is changing day-to-day. Read on for the full review.

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Wanhao Duplicator i3 Should Put an End to “Cheapest Printer” Kickstarters

Is the Wanhao Duplicator the best printer on the market? Not at all. Is it a contender for best low-price printer?Definitely. If you consider it a low priced kit printer instead of a finished product then it’s possible that, in its price class, it is hands down the best out there.

For somewhere between 300 and 500 dollars, the Duplicator is a hell of a printer. Also selling under the name Cocoon and Maker Select, the printer is a thin folded sheet steel frame clone of the Prusa i3. I opened the box expecting the most flagrant cost cutting I could imagine. I figured the steel would be paper thin. The holes wouldn’t line up. I expected the connections to be improperly terminated. I expected a fire.

The Duplicator six screws away from being fully assembled. When the manual says find a 1m x 1m flat area to work in it's not kidding. This table was too small.
The Duplicator six screws away from being fully assembled. When the manual says find a 1m x 1m flat area to work in it’s not kidding. This table was too small.

What I got was up and printing in under an hour. What I got was something designed by someone who cares, but with an obvious cost goal. As a bonus, it even printed pretty well. As mentioned, the basic shape of the frame is that of a Prusa i3. A horizontal bit holds the bed and y movement. A vertical bit is attached to the middle of that, making a T. It holds the X, Z, and nozzle.

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