Geocache Locator Is The Gift That Keeps On Giving

December 18, 2017 by Tom Nardi 5 Comments

Depending on how you look at things, the holidays could be seen as either an excuse to spend money or an excuse to get creative. We imagine many Hackaday readers would rather head to their workbench than the mall when it comes time for gift giving, and [Sean Hodgins] is no different. He came up with the idea of hiding geocaches around his nephew’s neighborhood and building him a locator device to find them. The locator itself is intended to grow with his nephew, allowing him to reprogram it or use its parts for something completely different down the road.

The main components tucked inside of the 3D printed case of the locator are an Adafruit Trinket, a GPS receiver, and a compass module. The Adafruit NeoPixel Ring is of course front and center, serving as the device’s display. To power the device there’s an old battery, a LiPo charger circuit, and a 5V converter.

One of the goals for the project was that it could be constructed out of things [Sean] already had laying around, so some concessions had to be made. The Trinket ended up having too few pins, the compass lacks an accelerometer, and the switches and buttons are a bit clunky for the build. But in the end it comes together well enough to get the job done, and at least he was able to clear some stuff out of his parts bins.

To allow its owner to disassemble and potentially rebuild it into something else later, no soldered joints were used in the construction of the locator. Everything is done with jumper wires, which lead to some interesting problem solving such as using a strip of pin header as a bus bar of sorts. A bit of heat shrink over the bundle holds everything together and prevents shorts.

Location-aware gadgets happen to be an extremely popular gift choice among the hacker crowd. We’ve covered everything from devices cobbled together from trash to hardware which could pass for a commercial product.

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There Are 10 Kinds Of Computers In The World

December 18, 2017 by Al Williams 50 Comments

There’s an old joke that there are 10 kinds of people in the world. Those who know binary, those who don’t, and those who didn’t see a base three joke coming. Perhaps [Dmitry Sokolov] heard that joke because he’s built a ternary (base 3) computer. He claims it is the first one to be built in the last 50 years. You can see a video about the device below. There’s also a video of the device with a nixie tube output.

You may not think of it often, but bit is a contraction of binary digit, so a ternary computer doesn’t have those. It has trits. The CPU operates on 3 trit words and uses nothing but multiplexers as building blocks. Instructions use 5 trits, some of which are a two-trit opcode and a 3 trit address of one of the 13 registers. The allure of using ternary, by the way, is that you can represent more numbers in fewer bits — um, trits, rather.

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Frankendrones: Toy Quads With A Hobby Grade Boost

December 18, 2017 by Tom Nardi 3 Comments

If you’re not involved in the world of remote controlled vehicles, you may not know there’s a difference between “toy” and “hobby” grade hardware. For those in the RC community, a toy is the kind of thing you’ll find at a big box store: cheap, works OK, but lacking in features and build quality. On the other hand, hobby hardware is generally considered to be of higher quality and performance, as well as being more modular. At the risk of oversimplification: if you bought it ready to go from a store it’s probably a toy, and if you built it from parts it would generally be considered hobby grade.

But with the rock bottom prices of toy quadcopters, that line in the sand is having a harder time than ever holding some in the community back. The mashup of toy and hobby grade components is giving rise to the concept of “frankendrones” that combine the low cost of toy hardware with key upgrades from the hobby realm. Quadcopter blogger [garagedrone] has posted a roundup of modifications made to the Bayangtoys X16, a $99 quadcopter which is becoming popular in the scene.

Some of the modifications are easy enough for anyone to do. Swapping out the original propellers for ones meant for the DJI Phantom 3 increases performance and doesn’t even require tools. If you want to go a bit further down the rabbit hole, you can cut off the X16’s battery connector and replace it with a standard XT60. That lets you use standard 3S LiPo batteries, which are cheaper and higher capacity than the proprietary ones the toy shipped with.

If you have a 3D printer, there are also a number of upgraded parts you can print which will bolt right onto the X16. Payload adapters, landing gear, and GoPro mounts are all just a few clicks (and some filament) away. This library of 3D printable parts is made possible in part because the X16’s frame is itself a clone of another toy quadcopter, the popular Syma X8C. So anything listed as compatible with the Syma X8C should work with the X16 (and vice versa).

Finally, if you really want to take the X16 to the next level, you can swap out the flight controller with an open source and better supported hobby grade model. Some of these flight controllers and associated new receivers can end up costing about half as much as the X16 did to begin with, but the vast improvement in performance and capability should more than make up for the cost.

We’ve covered previous efforts to increase the performance of low cost quadcopters in the past, as well as builds that put frugality front and center. It seems that no matter what your budget is a screaming angel of death is available if you want it.

Thanks to [Calvin] for the tip.

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3D Printed Key Saves The Day

December 18, 2017 by Adam Fabio 53 Comments

When [Odin917’s] parents went away on vacation, they took the apartment mailbox key with them. With the mail quickly piling up in the mailbox, he needed to get in there. He could have had the building super replace the lock, for a fee of course. Instead he had his parents email a photo of the key, which he used to 3D print his own copy.

Using a photograph as a template for a 3D printed copy is nothing new. We’ve covered it in-depth right here. However, this is the first time we’ve seen the technique put to use for good – in this case avoiding a hefty lock replacement fee.

He did his modeling in Autodesk’s free Fusion 360 CAD software. He then printed it out, and the box didn’t open. It took three revisions before the perfect key popped out of the printer. This particular mailbox uses a 4 pin tumbler, which makes it a bit less forgiving than other mailbox locks we’ve seen.

Admittedly this isn’t [Odin917’s] first time working with locks. Back in 2013, he submitted a parametric bump key model to Thingiverse.

Picking locks isn’t just for getting the mail. Locksport is a popular pastime for hardware hackers.

How Provably Loaded Dice Lead To Unprovable Cheating

December 18, 2017 by Donald Papp 16 Comments

Here’s a really interesting writeup by [Mike] that has two parts. He shows that not only is it possible to load wooden dice by placing them in a dish of water, but that when using these dice to get an unfair advantage in Settlers of Catan, observation of dice rolls within the game is insufficient to prove that the cheating is taking place.

[Mike] first proves that his pair of loaded dice do indeed result in a higher chance of totals above seven being rolled. He then shows how this knowledge can be exploited by a Settlers of Catan player to gain an average 5-15 additional resource cards in a typical game by taking actions that target the skewed distribution of the loaded dice.

The second part highlights shortcomings and common misunderstandings in current statistical analysis. While it’s possible to prove that the loaded dice do have a skewed distribution by rolling them an arbitrary number of times, as [Mike] and his wife do, it is not possible to detect this cheating in a game. How’s that? There are simply not enough die rolls in a game of Settlers to provide enough significant data to prove that dice distribution is skewed.

Our staff of statistics Ph.D.s would claim that [Mike] overstates his claims about shorcomings in the classical hypothesis testing framework, but the point remains that it’s possible to pass through any given statistical testing process by making the effect just small enough. And we still think it’s neat that he can cheat at Settlers by soaking wooden dice in water overnight.

This isn’t the first time we’ve seen Settlers of Catan at the center of some creative work. There’s this deluxe, hand-crafted reboot, and don’t forget the electroshock-enabled version.

[via Reddit; images from official Catan site]

Books You Should Read: The 3D Printing Handbook

December 18, 2017 by Brian Benchoff 12 Comments

3D printing was invented in the 80s, twenty years passed, patents expired, and then several diverse uses for 3D printing technology were found. As such, the tips and techniques for 3D printing — especially filament-based printing — have been discussed and documented almost entirely on the Internet, mostly in chat rooms, forums, and YouTube videos. Everything you could ever want to know about 3D printing is available on the Internet, but that doesn’t mean you’ll be able to find it.

There have been dozens of books published as a guidebook to 3D printing over the years, and some of those are even in their second edition. Yes, despite the disappearance of 3D printers from the headlines of TechCrunch, and despite the massive public disillusionment of computer-controlled hot glue guns, there are still people that want to learn about 3D printers. There’s actually a market for 3D printing guidebooks, and people are buying them.

The latest such guidebook for 3D printing is The 3D Printing Handbook from 3D Hubs. 3D Hubs has been around for a while, and can best be described as, ‘3D Printing as a Service’. The usual use case for 3D Hubs is that someone would upload a 3D model to 3D Hubs, and get a quote from someone with a 3D printer. This quote could come from a professional 3D printing outfit with machines that cost more than a house to someone with a LulzBot or Prusa in their garage. 3D Hubs is going to be fantastic when people realize you can do CNC milling on the service as well.

This book was written by Ben Redwood, Filemon Schöffer, and Brian Garret, all employees of 3D Hubs. In one way or another, 3D Hubs has a hand in every conceivable type of 3D printing technology, and this book aims to be an introduction to the uses of these technologies, and a guidebook on how to use 3D printing technology the right way. There’s a question with this book: does it live up to expectations, and for that matter, can any book live up to the expectation of being a ‘guide to 3D printing?’

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A Dynamometer For Measuring Motor Power

December 18, 2017 by Jenny List 26 Comments

If you have ever ventured into the world of motor vehicles you may be familiar with a dynamometer, possibly as a machine to which your vehicle is taken for that all-important printout that gives you bragging rights (or not) when it comes to its ability to lay down rubber. A dynamometer is essentially a variable load for a rotating shaft, something that converts the kinetic energy from the shaft into heat while measuring the power being transferred.

Most of us will never have the chance to peer inside our local dyno, so a term project from a group of Cornell students might be something of interest. They’ve built a dynamometer for characterising small electric motors, and since their work is part of their degree courses, their documentation of it goes into great detail.

Their dynamometer takes the form of a shaft driving a stainless steel disc brake upon which sit a pair of calibers mounted on a fixed shaft that forms a torsion bar. The whole is mounted in a sturdy stainless steel chassis, and is studded with sensors, a brace of strain gauges and a slotted disc rotation sensor. It’s not the largest of dynamometers, but you can learn about these devices from their work just as they have.

This is a project sent to us by [Bruce Land], one of many from his students that have found their way to these pages. His lectures on microcontrollers are very much worth a look.