Printed It: Toolbag Essentials

May 7, 2018 by 26 Comments

While complex devices assembled from 3D printed components are certainly impressive, it’s the simple prints that have always held the most appeal to me personally. Being able to pick an object up off the bed of your printer and immediately put it to use with little to no additional work is about as close as we can get to Star Trek style replicators. It’s a great demonstration to show off the utility of your 3D printer, but more importantly, having immediate access to some of these tools and gadgets might get you out of a jam one day.

With that in mind, I thought we’d do things a little differently for this installment of Printed It. Rather than focusing on a single 3D model, we’ll be taking a look at a handful of prints which you can put to practical work immediately. I started by selecting models based on the idea that they should be useful to the average electronic hobbyist in some way or another, and relatively quick to print. Each one was then printed and evaluated to determine its real-world utility. Not all made the grade.

Each model presented here is well designed, easy to print, and most critically, legitimately useful. I can confidently say that each one has entered into my standard “bag of tricks” in some capacity, and I’m willing to bet a few will find their way into yours as well.

Continue reading “Printed It: Toolbag Essentials” →

Double The Resolution, From An Arduino ADC

May 7, 2018 by 29 Comments

Analog-to-digital converters, or ADCs, are somewhat monolithic devices for most users, a black box that you ask nicely for the value on its input, and receive a number in return. For most readers, they will be built into whatever microcontroller is their platform of choice, and their resolution will be immutable, set by whatever circuitry is included upon the die. There are a few tricks that can be employed to get a bit more from a stock ADC though, and [Neris] has taken a look at a couple of them.

The first circuit doubles the resolution of an ADC, in this case, that of the Atmel chip in an Arduino, by converting its output from an integer to a signed integer. It performs this task with a precision rectifier, rectifying around a zero-crossing point half-way through the range of the analog value to be read and supplying a sign bit to the Arduino. The Arduino measures the rectified analog value to an integer, and applies the appropriate sign from the supplied bit value.

The second circuit takes a variation on the same technique but with two ADCs instead of one. A pair of PIC chips are used with their voltage references stacked one above the other, by taking both readings in combination a result with double the resolution can be derived.

You might ask why bother with these techniques. After all, there are plenty of higher-resolution ADCs on the market. But they’re useful techniques to know, should you ever need to extract the proverbial quart from a pint pot.

If ADCs are a mystery to you, you’re in luck. [Bil Herd] gave us a comprehensive introduction to the subject.

The Aluminum Wiring Fiasco

May 7, 2018 by 141 Comments

Someone who decides to build a house faces a daunting task. It’s hard enough to act as the general contractor for someone else, but when you decide to build your own house, as my parents did in the early 1970s, it’s even tougher. There are a million decisions to make in an information-poor and rapidly changing environment, and one wrong step can literally cast in stone something you’ll have to live with forever. Add in the shoestring budget that my folks had to work with, and it’s a wonder they were able to succeed as well as they did.

It was a close call in a few spots, though. I can recall my dad agonizing over the wiring for the house. It would have been far cheaper to go with aluminum wiring, with the price of copper wire having recently skyrocketed. He bit the bullet and had the electrician install copper instead, which ended up being a wise choice, as houses that had succumbed to the siren call of cheaper wiring would start burning down all over the United States soon thereafter.

What happened in the late 60s and early 70s in the residential and commercial electrical trades was an expensive and in some cases tragic lesson in failure engineering. Let’s take a look at how it all happened.

Continue reading “The Aluminum Wiring Fiasco” →

3D Printed Bicycle Tire Not Full Of Hot Air

May 7, 2018 by 30 Comments

To show off its new TPU filament called PRO FLEX, BigRep GmbH posted a video showing a 3D printed bike tire that uses a flexible plastic structure instead of air. The video shows them driving the bike around Berlin.

According to the company, the filament will allow the creation of a large number of industrial objects not readily built with other types of plastic. Their release claims the material has high temperature resistance, low temperature impact resistance, and is highly durable. Applications include gear knobs, door handles, skateboard wheels, and other flexible parts that need to be durable.

The material has a Shore 98 A rating. By way of comparison, a shoe heel is typically about 80 on the same scale and an automobile tire is usually around 70 or so. The hard rubber wheels you find on shopping carts are about the same hardness rating as PRO FLEX.

Obviously, a bicycle tire is going to take a big printer. BigRep is the company that makes the BigRep One which has a large build volume. Even with a wide diameter tip, though, be prepared to wait. One of their case studies is entitled, “Large Architectural Model 3D Printed in Only 11 Days.” Large, in this case, is a 1:50 scale model of a villa. Not tiny, but still.

We’ve looked at other large printers in the past including 3DMonstr, and the Gigimaker. Of course, the latest trend is printers with a practically infinite build volume.

Continue reading “3D Printed Bicycle Tire Not Full Of Hot Air” →

AH-1 Cobra Tap Handle Pours On The Fun

May 7, 2018 by 19 Comments

Ayn Rand said, “If it’s worth doing, it’s worth overdoing.” As far as we’re concerned those are words to live by, and something that’s exemplified by most of the posts on this site. She also said some really suspect stuff about the disabled and Native Americans and reality, but you’ve got to take the good with the bad and all that.

We don’t know how much Rand [Will Weber] has read, but we’re willing to bet he’d agree about overdoing it. He recently documented a very cool 3D printed tap handle that’s designed to look like the B8 flight stick from an AH-1 Cobra helicopter. But this is no static piece of plastic, in the video after the break, he demonstrates how each button on the flight stick triggers a different weapons sound effect.

The 3D print is separated up into a number of sections so that the stick can be assembled in pieces. Not only does this make it an easier print, it also allows for the installation of the electronics.

For the Arduino aficionados out there, we have some bad news. Rather than putting in a general purpose microcontroller, [Will] went the easy route and used an Adafruit Audio FX Mini Sound Board. These boards have their own onboard storage for the audio files and don’t require a microcontroller to function. It makes it super easy to add sound effects or even music to your projects; just pair it with a power supply, a couple of buttons, and a speaker.

The finish work on the printed parts looks excellent. We can only imagine how much fun [Will] had sanding inside all the little nooks and crannies to get such a smooth final result. While some might complain about the idea of a tap handle needing to be recharged occasionally, we think the satisfaction of firing off a few rockets every time you grab a glass is more than worth it.

While this isn’t the first unique tap handle we’ve covered here at Hackaday, it’s certainly the most flight-ready. Continue reading “AH-1 Cobra Tap Handle Pours On The Fun” →

Algorithms For Visual Learners

May 6, 2018 by 10 Comments

Computer programming is a lot like chess. It is fairly simple to teach people the moves. But knowing how the pieces move isn’t the reason you can win. You have to understand how the pieces work together. It is easy to learn the mechanics of a for loop or a Java interface. But what makes programs work are algorithms. There are many books and classes dedicated to algorithms, but if you are a visual learner, you might be interested in a site that shows visualizations of algorithms called VisuAlgo.

The site is from [Dr. Steven Halim] and is meant for students at the National University of Singapore, but it is available “free of charge for Computer Science community on earth.” We suspect if any astronauts or cosmonauts wanted to use it in space, they’d be OK with that, too.

The animations and commentary take you through algorithms ranging from the common — sorting and linked lists — to the obscure — Steiner and Fenwick trees. Each animation frame has some commentary, so it isn’t just pretty pictures. The site is available in many languages, too.

Many of the animations allow you to set up problems and execute them using a C-like pseudo language. When it executes, you can watch the execution pointer and a box comments on the current operation. For example, in the linked list unit, you can create a random doubly linked list and then search it for a particular value. Not only can you see the code, but the graphical representation of the list will update as the code runs.

The site allows you to register for free to get additional features, but we didn’t and it was still a great read about many different data structures. Also, a few of the commentary slides require you to show you are actually a computer science professor — we assume there’s some copyright issue involved because it is only a few.

This site is a great example of how many free educational resources are out there on the web. It isn’t just computer science either. MITx — or more generally, edX — has some great hardware classes and many other topics

The Adafruit Feather Is A Thing

May 6, 2018 by 44 Comments

A few years ago, Adafruit launched the Feather 32u4 Basic Proto. This tiny development board featured — as you would expect — an ATMega32u4 microcontroller, a USB port, and a battery charging circuit for tiny LiPo batteries. It was, effectively, a small Arduino clone with a little bit of extra circuitry that made it great for portable and wearable projects. In the years since, and as Adafruit has recently pointed out, the Adafruit Feather has recently become a thing. This is a new standard. Maxim is producing compatible ‘wings’ or shields. If you’re in San Francisco, the streets are littered with Feather-compatible boards. What’s the deal with these boards, and why are there so many of them?

The reason for Adafruit’s introduction of the Feather format was the vast array of shields, hats, capes, clicks, props, booster packs, and various other standards. The idea was to bring various chipsets under one roof, give them a battery charging circuit, and not have a form factor that is as huge as the standard Arduino. The Feather spec was finalized and now we have three-phase energy monitors, a tiny little game console, LoRaWAN Feathers, and CAN controllers.

Of course, the Feather format isn’t just limited to Adafruit products and indie developers. The recently introduced Particle hardware is built on the Feather format, giving cellular connectivity to this better-than-Arduino format. Maxim is producing some development boards with the same format.

So, do we finally have a form factor for one-off embedded development that isn’t as huge or as wonky as the gigantic Arduino with weirdly offset headers? It seems so.