Ask Hackaday: What’s Your Favorite Internet Relic?

December 3, 2016 by Gerrit Coetzee 112 Comments

[Sadiq Mohamed] posted this great list of light bulb jokes in our post about drones changing light bulbs. This favored relic used to exist on a Compuserve SIG, but fortunately a dedicated user had saved the list.

There have been virtual worlds long before our computers could render anything but potatoes with anime faces. Bulletin boards, mailing lists, and forums dominated and then fell, for the most part, to social media. In a way even the personal home page has gone to the wayside. (remember geocities?)

The internet has gone through many phases of development. We’ve experimented with lots of concepts and when they fail or go out of style, there are ghost towns of information left untouched.

However, we remember. I still think fondly of my old shell server. Some of it is even history worthy enough to be in the books. What’s your favorite piece of internet gone by or just plain internet obscura? An old joke? A book five layers deep in a file structure somewhere. Or maybe just the 1959 definition of the word, “hack,” in the Tech Model Railroad Club’s first edition dictionary.

Ask Hackaday: What Should Father Christmas Bring From Shenzhen?

November 26, 2016 by Jenny List 59 Comments

Imagine this, you have a friend who grew up in Shenzhen, China. The place from whence all your really cool electronics come these days. They speak Chinese in a way only someone born there can, and given that you know them through a shared interest in hardware hacking you can assume they know their way round those famous electronics marts of their home town.

Now, imagine that in a rash move, your friend has offered to pick up a few bits for you on their next trip home. A whole city-sized electronic candy store opens up in front of you, but what do you ask for them to seek out?

Before you continue, consider this. Why has Shenzhen become the powerhouse of electronic manufacturing (and everything else) that it is? Economists will give you pages of fascinating background, but if you want a simple answer it is that those electronics are produced for export, and that its citizens are only too happy to export them to you. Therefore if you want to get your hands on electronics from Shenzhen you do not need a friend who is a native of the city, all you need is a web browser and a PayPal account.

We have all become used to seeking out the cool stuff and eagerly waiting for a padded envelope from China Post a week or two later, so there are very few items that are worth putting a friend to the extra task of finding. At which point you realize that it is the candy store rather than the candy itself which is so alluring, and you ask your friend for a video walkthrough with commentary of their travels through the electronics marts. Oh, and maybe a Chinese Raspberry Pi with red solder resist, just for the collection.

If you had a friend about to board a plane to Shenzhen, what would you ask them to find for you that you can’t just buy for yourself online? Remember, nothing that’ll land them with awkward questions at either airport, nor anything that’ll land them with a hefty customs bill. That’s a very good way to end a friendship.

Huaqiangbei skyline image: Edward Rivens (PD) via Wikimedia Commons.

Ask Hackaday: Did Video Games Influence Your Career?

November 24, 2016 by Gerrit Coetzee 49 Comments

Apex Minecraft hosting recently held a scholarship competition. The person who sent in the best essay would win a $2,000 scholarship. The winning essay starts, “Five years ago, at age 13, I built an entire computer from scratch. Assembled from basic components: wires, torches, repeaters, pistons, and blocks, it was capable of rendering images to a display, multiplying and dividing numbers, and even calculating square roots.” I had to read it twice before it clicked that he was talking about a computer built entirely in a fictional universe.

It’s no wonder that he’s now a freshman at college, pursuing a degree in computer engineering. After reading this, I started to reminisce. The first computer I ever had access to was my mother’s laptop. It had an install of QBASIC on it, and I remember using it to make a few text based games. Later on when we got our first family computer I remember spending hours getting no better at video game programming using QBASIC.

It went on and on. I remember doing AI for video games in DarkBasic. I remember doing physics and collisions. Eventually I found my way to html, then php, to make websites about games (which are too terrible to share with you). So when the time came to program robots I was absolutely fearless. It just seemed like such a natural extension of what I already knew that it never occurred to me to be thankful for the time I spent trying to make my own simple little games until much later.

In the end I am still occasionally making little forays into game programming when I want to learn a new language or get back up to speed. It never occurred to me that perhaps this was just the way I’ve always learned a language.

Later on in the winner’s essay he goes on to describe his minecraft community. They taught new players. They taught themselves. They hung out and became friends. The writer gained a sense of self as a user of computers, a teacher of skills, a good member of a community, and a solver of problems. Unlike some of his classmates he won’t go to college and have to learn if he’s good enough. He’ll already know. All it took was a silly block based game.

Did any of you have seemingly frivolous endeavors show up as a foundation for your life and learning far into the future? Tell in the comments below how this ended up shaping your career.

RC receiver to arduino converter for BB-8

Ask Hackaday: How Do You Convert Negative Voltages To Positive?

November 14, 2016 by Steven Dufresne 81 Comments

I have a good background working with high voltage, which for me means over 10,000 volts, but I have many gaps when it comes to the lower voltage realm in which RC control boards and H-bridges live. When working on my first real robot, a BB-8 droid, I stumbled when designing a board to convert varying polarities from an RC receiver board into positive voltages only for an Arduino.

Today’s question is, how do you convert a negative voltage into a positive one?

In the end I came up with something that works, but I’m sure there’s a more elegant solution, and perhaps an obvious one to those more skilled in this low voltage realm. What follows is my journey to come up with this board. What I have works, but it still nibbles at my brain and I’d love to see the Hackaday community’s skill and experience applied to this simple yet perplexing design challenge.

The Problem

I have an RC receiver that I’ve taken from a toy truck. When it was in the truck, it controlled two DC motors: one for driving backwards and forwards, and the other for steering left and right. That means the motors are told to rotate either clockwise or counterclockwise as needed. To make a DC motor rotate in one direction you connect the two wires one way, and to make it rotate in the other direction you reverse the two wires, or you reverse the polarity. None of the output wires are common inside the RC receiver, something I discovered the hard way as you’ll see below.

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Ask Hackaday: DIY Handwriting Recognition

October 12, 2016 by Elliot Williams 40 Comments

Computer handwriting recognition is very cool by itself, and it’s something that we’d like to incorporate into a project. So we went digging for hacker solutions, and along the way came up with an interesting bit of history and some great algorithms. We feel like we’ve got a good start on that front, but we’re stuck on the hardware tablet sensor itself. So in this Ask Hackaday, we’re going to make the case for why you could be using a tablet-like device for capturing user input or doing handwriting recognition, and then we’re going to ask if you know of any good DIY tablet designs to make it work.

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Ask Hackaday: How Do You Make A Hotplate?

September 28, 2016 by Brian Benchoff 119 Comments

Greetings fellow nerds. The Internet’s favorite artificial baritone chemist has a problem. His hotplates burn up too fast. He needs your help to fix this problem.

[NurdRage] is famous around these parts for his very in-depth explorations of chemistry including the best ways to etch a PCB, building a thermometer probe with no instructions, and chemical synthesis that shouldn’t be performed by anyone without years of experience in a lab. Over the past few years, he’s had a problem: hotplates suck. The heating element is usually poorly constructed, and right now he has two broken hotplates on his bench. These things aren’t cheap, either: a bare-bones hotplate with a magnetic stirrer runs about $600.

Now, [NurdRage] is asking for help. He’s contacted a few manufacturers in China to get a hundred or so of these hotplate heating elements made. Right now, the cost for a mica and metal foil hotplate is about $30 / piece, with a minimum order quantity of 100. That’s $3,000 that could be better spent on something a bit more interesting than a heating element, and this is where you come in: how do you build the heating element for a hotplate, and do it cheaply?

If you buy a hotplate from the usual lab equipment supplier, you’ll get a few pieces of mica and a thin trace of metal foil. Eventually, the metal foil will oxidize, and the entire hotplate will stop working. Repairs can be done with copper tape, but by the time that repair is needed, the heating element is already on its way out.

The requirements for this heating element include a maximum temperature of around 350 ºC. That’s a fair bit hotter than any PCB-based heat bed from a 3D printer gets, so consider that line of reasoning a dead end. This temperature is also above what most resins, thermoplastics, and composites can handle, which is why these hotplates use mica as an insulator.

Right now, [NurdRage] will probably end up spending $3,000 for a group buy of these heating elements. That’s really not that bad – for the price of five hotplates, he’ll have enough heating elements to last through the rest of his YouTube career. There must be a better way, though, so if you have an idea of how to make a high-temperature heating element the DIY way, leave a note in the comments.

Ask Hackaday: Help Me Choose A ‘Scope

September 20, 2016 by Jenny List 89 Comments

If there is one instrument that makes an electronic engineer’s bench, it is the oscilloscope. The ability to track voltages in the time domain and measure their period and amplitude is one akin to a light in the darkness, it turns a mere tinkerer with circuits into one in command of them. Straightforward add-on circuits can transform a basic oscilloscope into a curve tracer, frequency response display, and much more, and modern oscilloscopes offer a dizzying array of useful measurement features unimaginable to engineers only a few years ago. And I need your help to pick a new one.

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