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Longform articles, the best of what the Hackaday writing crew has to offer.

Two Guys, A Hotel Room And A Radio Fire

May 13, 2016 by 45 Comments

Can you build a HF SSB radio transciever in one weekend, while on the road, at parts from a swap meet? I can, but apparently not without setting something on fire.

Of course the swap meet I’m referring to is Hamvention, and Hamvention 2016 is coming up fast. In a previous trip to Hamvention, Scott Pastor (KC8KBK) and I challenged ourselves to restore tube radio gear in a dodgy Dayton-area hotel room where we repaired a WW2 era BC-224 and a Halicrafters receiver, scrounging parts from the Hamfest.

Our 2014 adventures were so much fun that it drove us to create our own hacking challenge in 2015 to cobble together a <$100 HF SSB transceiver (made in the USA for extra budget pressure), an ad-hoc antenna system, put this on the air, and make an out-of-state contact before the end of Hamvention using only parts and gear found at Hamvention. There’s no time to study manuals, antennas, EM theory, or vacuum tube circuitry.  All you have are your whits, some basic tools, and all the Waffle House you can eat.  But you have one thing on your side, the world’s largest collection of surplus electronics and radio junk in one place at one time.  Can it be done?

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To See Within: Making Medical X-rays

May 12, 2016 by 47 Comments

I was a bit of a lost soul after high school.  I dabbled with electrical engineering for a semester but decided that it wasn’t for me – what I wouldn’t give for a do-over on that one. In my search for a way to make money, I stumbled upon radiologic technology – learning how to take X-rays. I figured it was a good way to combine my interests in medicine, electronics, and photography, so after a two-year course of study I got my Associates Degree, passed my boards, and earned the right to put “R.T.(R) (ARRT)” after my name.

That was about as far as that career went. There are certain realities of being in the health care business, and chief among them is that you really have to like dealing with the patients. I found that I liked the technology much more than the people, so I quickly moved on to bigger and better things. But the love of the technology never went away, so I thought I’d take a look at exactly what it takes to produce medical X-rays, and see how it’s changed from my time in the Radiology Department.

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Path To Craftsmanship: Safety, Cleanliness, And Documentation As Habits

May 12, 2016 by 49 Comments

When I started boxing classes I was told, at my level, I could do just as much good for my form by doing core exercises such as crunches, running, push-ups, and pull-ups for a month as I could by doing the class. I consder habits like safety, cleanliness, and documentation to be habits that influence the quality of hacks much the same way. They’re not really related, and the work can get done without them, but their implementation alone improves the quality of everything you do at the workbench.

The best mechanic I’ve ever met had a well-organized shop. All of his employees wore nitrile gloves when they worked on engines to protect their hands from the chemicals inside. They used ear protection and safety glasses. His rates were low, and the car was always repaired fast. I never had to go back for the same repair twice. He knew exactly what repairs were done, and even kept the parts removed from my vehicle to show me if I desired. I got some of the most fantastic explanations of why parts failed from him. Two blocks down the street was a shop which was unorganized and had double rates. The employees were always sitting on the waiting chairs in the lounge. It took one trip there to never return.

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Looking Mains Voltage In The Eye And Surviving

May 11, 2016 by 198 Comments

It is often a surprise to see how other people react to mains electricity when they encounter it in a piece of equipment. As engineers who have dealt with it both personally and professionally for many years it is easy to forget that not everyone has had that experience. On one hand we wince at those who dive in with no fear of the consequences, on the other we are constantly surprised at the number of people who treat any item with more than a few volts in it as though it was contaminated with radioactive anthrax and are scared to even think about opening it up.

We recently had a chat among the Hackaday writers about how we could approach this subject. The easy way out is to be all Elf-and-Safety and join the radioactive anthrax crowd. But the conclusion we came to was that this site is a resource for hackers and makers. Some of you are going to lift the lid on boxes containing significant voltages no matter what, so we thought we’d help you do it safely rather than just listen for the distant screams.

So here follows the first in a series on how to approach electronic devices containing high voltages, and live to tell the tale. By “high voltages” we mean anything up to mains voltages, and those directly derived from them such as the few hundred volts rectified DC you’ll find in a switch-mode PSU. For multi-kilovolt EHT you’ll have to wait for another article, because that is an entire subject in itself. We’ll mention these higher voltages in passing, but their detail is best left for a Hackaday colleague with more pertinent experience.

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Don’t Ignore The Artist’s Supply Store

May 10, 2016 by 49 Comments

So it’s Saturday morning and you’ve found yourself with an urge to build something involving copper plates or carbon electrodes. Maybe you need a metallic powder for a chemistry experiment. Casting supplies? Pure lead? Copper mesh? Silver wire?  Odd tools? Exceedingly caustic etchants?  There’s a store that sells it all, and it’s not usually frequented by hackers: the art store.

If you know where to look, the store is full of useful things. Each method of expression in art has its own set of supplies; a bountiful collection of various processes and the useful things therein. I grew up in a city that did not have a real art supply store. It had one of those big box craft stores that assault you with glittery plasticized flowers and terrible manufactured scents. When I moved to a different city and walked over to the local art supply to purchase some new pens I ended up staying for a few hours just looking at all the cool things they had for sale.

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The Coming Wide-Spread Use Of Drones In Agriculture

May 9, 2016 by 39 Comments

Whether you call them UAVs (Unmanned Aerial Vehicles), UAS (Unmanned Aerial System), Drones, or something less polite – people are more familiar than ever with them. We’ll call them drones, and we’re not talking about the remote-controlled toy kind – we’re talking about the flying robot kind. They have sensors (GPS and more), can be given a Flight Plan (instructions on where to go), and can follow that plan autonomously while carrying out other instructions – no human pilot required. Many high-end tractors are already in service with this kind of automation and we’ve even seen automated harvesting assistance. But flying drones are small and they don’t plant seeds or pull weeds, so what exactly do they have to do with agriculture?

There are certain things that drones are very good at, and there are things in agriculture that are important but troublesome to do or get. Some of these things overlap, and in those spaces is where a budding industry has arisen.

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Up Your CAD Game With Good Reference Photos

May 6, 2016 by 28 Comments

I’ve taken lots of reference photos for various projects. The first time, I remember suffering a lot and having to redo a model a few times before I got a picture that worked. Just like measuring parts badly, refining your reference photo skills will save you a lot of time and effort when trying to reproduce objects in CAD. Once you have a model of an object, it’s easy to design mating parts, to reproduce the original, or even for milling the original for precise alterations.

I’m adding some parts onto a cheap food dehydrator from the local import store. I’m not certain if my project will succeed, but it’s a good project to talk about taking reference photos. The object is white, indistinct, and awkward, which makes it a difficult object to take a good photo for reference use in a CAD program. I looked around for a decent tutorial on the subject, and only found one. Maybe my Google-fu wasn’t the best that day. Either way, It was mostly for taking good orthogonal shots, and not how to optimize the picture to get dimensions out of it later.

There are a few things to note when taking a reference photo. The first is the distortion and the setup of your equipment to combat it. The second is including reference scales and surfaces to assist in producing a final model from which geometry and dimensions can be accurately taken. The last is post-processing the picture to try to fight the distortion, and also to prepare it for use in cad and modeling software.

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