You Might Want To Buy A Quadcopter Now

NBC News has reported the US Government may implement regulations in the coming days that would require anyone who buys an unmanned aircraft system to register that device with the US Department of Transportation.

The most simplistic interpretation of this news is that anyone with a DJI Phantom or a model aircraft made out of Dollar Tree foam board would be required to license their toys. This may not be the case; the FAA – an agency of the US DoT – differentiates between unmanned aircraft systems and model aircraft.

This will most likely be the key thing to watch out for in any coming regulation. The FAA defines model aircraft as, “an unmanned aircraft that is capable of sustained flight in the atmosphere; flown within visual line of sight of the person operating the aircraft; and flown for hobby or recreational purposes.” Additionally, the FAA may not make any regulations for model aircraft. While this means planes and quads flown without FPV equipment may be left out of this regulation, anything flown ‘through a camera’ would be subject to regulation.

Washington DC Electrified with Raw Sewage

Completely unrelated to the current political climate in the United States, did you know Washington D.C. is partially powered by a sewage plant? No, seriously.

That’s right, just this week the D.C. Water utility company has announced a bioenergy facility that makes use of resident’s waste water into producing methane gas which can than be burned to generate electricity — To the tune of 10 megawatts! The facility is saving the company an estimated $10 million a year in energy bills.

Simply put, the liquid is removed from the sewage water and the solids are refined into a type of fuel. Those solids are heated, mixed, and sterilized into a form that can be easily digested by a certain type of microbe, which then in turn produce methane for burning. For a more detailed explanation, check out the info-graphic from the Washington Post explaining the entire process.

And on a smaller scale, you could do something like this in your very own backyard.

Make A Cheap (And Dangerous) Automated Flamethrower

Nothing lights up the night like a quick blast from a flamethrower, but there is a reason why you can’t buy them in the Halloween decoration aisle at Target. They are dangerous, for fairly obvious reasons. [Erco] seems to have no particular fear of death, though, and he shows how you can build a simple flamethrower with a small candle, a servo, Arduino and a can of hairspray. Tresemme Extra Strong Hold, in particular, although we don’t think the exact type matters that much. All he did was to mount the candle in front of the hairspray, then mount the servo so the arm presses the spray head down. The candle does the rest, lighting the highly flammable propellant in the hairspray to produce the flamethrower effect. [Erco] is using four of these, which are co-ordinated to fire in time with music.

This one seems a bit risky. Servos have a habit of locking, and there is nothing stopping these from locking in the open position, or sticking there if the Arduino crashes. A relay or other switch that reverts to an off position when the power is removed would have been more suitable here. Secondly, there is no emergency off switch. [Erco] has wired the Arduino up next to the flamethrower itself, so you are going to have to reach in to disconnect it. That is risky enough, but he also tried a 4-way configuration that would have been impossible to disable in the event of a problem (shown in the accompanying images). Thirdly, there is no fire protection between the can of hairspray and the open flame, so if the spray head melts or fails from the heat, it’s game over. Finally (and most importantly), where are the fire extinguishers? We’d like to hear how you’d build this with safety in mind. Let us know in the comments below.

We’re big fans of flames and explosions: we’ve have seen a couple of Survival Research Laboratory shows and were blown away by their destructive pyrotechnics. But, as SRL head Mark Pauline said in a recent talk, “when things blow up at an SRL show, it’s on purpose”.

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WiFi Fob Acquaints OLED with ESP

When you think of WiFi in projects it’s easy to get into the rut of assuming the goal is to add WiFi to something. This particular build actually brings WiFi awareness to you, in terms of sniffing what’s going on with the signals around you and displaying them for instant feedback.

[0miker0] is working on the project as his entry in the Square Inch Project. It’s an adapter board that has a footprint for the 2×4 pin header of an ESP8266-01 module, and hosts the components and solder pads for a 128×64 OLED display. These are becoming rather ubiquitous and it’s not hard to figure out why. They’re relatively inexpensive, low-power, high-contrast, and require very few support components. From the schematic in the GitHub Repo it looks like 5 resistors and 7 caps.

The video below shows off two firmware modes so far. The first is an AP scan that reads out some information, the second is a weather-display program. Anyone who’s worked with the ESP modules knows that they have the potential to gather all kinds of data about WiFi signals — one of our favorite demos of this is when [cnlohr] used it to create a 3d light painted map of his WiFi signal strength. Chuck a rechargeable LiPo on this thing, tweak the example code for your needs, and you have a new gadget for wardriving-nouveau.

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Code Craft: When #define is Considered Harmful

An icon of Computer Science, [Edsger Dijkstra], published a letter in the Communications of the Association of Computer Machinery (ACM) which the editor gave the title “Go To Statement Considered Harmful“. A rousing debate ensued. A similar criticism of macros, i.e. #define, in C/C++ may not rise to that level but they have their own problems.

Macros are part of the preprocessor for the C/C++ languages which manipulates the source code before the actual translation to machine code. But there are risks when macros generate source code. [Bjarne Stroustrup] in creating C++ worked to reduce the need and usage of the preprocessor, especially the use of macros. In his book, The C++ Programming Language he writes,

Don’t use them if you don’t have to. Almost every macro demonstrates a flaw in the programming language, in the program, or in the programmer.

As C retrofitted capabilities of C++, it also reduced the need for macros, thus improving that language.

With the Arduino using the GNU GCC compilers for C and C++ I want to show new coders a couple of places where the preprocessor can cause trouble for the unwary. I’ll demonstrate how to use language features to achieve the same results more cleanly and safely. Of course, all of this applies equally when you use any of these languages on other systems.

We’re only going to be looking at macros in this article but if you want to read more the details about them or the preprocessor see the GNU GCC Manual section on the preprocessor.

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Show a Quadcopter Flight on Google Earth for Under Ten Bucks

[Joop Brokking] wanted to know where his quadcopter was and had been. He thought about Google Earth, but assumed it would be difficult to get the GPS data and integrate it with Google’s imagery. But he discovered it was easier than he thought. He wound up spending around $10, although if his ‘copter didn’t already have GPS, it would have been more.

Hardware-wise, [Joop] made a pretty straightforward data logger using a small Arduino (a Pro Mini) and an SD Card (along with an SD breakout board). With this setup, NMEA data from the GPS comes in the Arduino’s serial port and winds up on the SD Card.

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Hacklet 80 – Gigahertz Projects

Somewhere between the HF projects many of us have worked on, and the visible light spectrum lies the UHF, EHF, SHF, and THF. That’s Ultra, Extremely, Super, and Tremendously High Frequency for those who aren’t in the know. All of them involve frequencies in the gigahertz and terahertz range. While modern computers have made gigahertz a household term, actually working with signals in the gigahertz frequency range is still a daunting prospect. There have always been an elite group of hackers, makers, and engineers who tinker with projects using GHz frequencies. This week’s Hacklet is about some of the best GHz projects on!

radar1We start with [Luke Weston] and Simple, low-cost FMCW radar. For years people like Hackaday’s own [Gregory L. Charvat] have been building simplified radar systems and documenting them for the rest of us. [Luke’s] goal is to make radar systems like this even more accessible for the average hacker. He’s put all the specialized parts on one board. Rather than large Mini Circuits modules, [Luke] went with Hittite microwave parts in chip scale packages. Modulation comes from a Microchip MCP4921 mixed signal DAC. The system works, and has demonstrated transmission and reception 5 GHz to 6 GHz bands. [Luke] has even demonstrated detection of objects at close range using a scope.

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