The Zombie Rises Again: Drone Registration Is Back

December 14, 2017 by Jenny List 69 Comments

It’s a trope of horror movies that demonic foes always return. No sooner has the bad guy been dissolved in a withering hail of holy water in the denoeument of the first movie, than some foolish child in a white dress at the start of the next is queuing up to re-animate it with a careless drop of blood or something. If parents in later installments of popular movie franchises would only keep an eye on their darn kids, it would save everybody a whole lot of time!

The relevant passage can be found in section 1092(d) of the National Defense Authorization Act, on page 329 of the mammoth PDF containing the full text, and reads as follows:

(d) RESTORATION OF RULES FOR REGISTRATION AND MARKING OF UNMANNED AIRCRAFT
.—The rules adopted by the Administrator
of the Federal Aviation Administration in the matter of registration
and marking requirements for small unmanned aircraft (FAA-2015-
7396; published on December 16, 2015) that were vacated by the
United States Court of Appeals for the District of Columbia Circuit
in Taylor v. Huerta (No. 15-1495; decided on May 19, 2017) shall
be restored to effect on the date of enactment of this Act.

This appears to reverse the earlier decision of the court, but does not specify whether there has been any modification to the requirements to prevent their being struck down once more by the same angle of attack. In particular, it doesn’t change any of the language in the FAA Modernization Act of 2012, which specifically prevents the Agency from regulating hobby model aircraft, and was the basis of Taylor v. Huerta. Maybe they are just hoping that hobby flyers get fatigued?

We took a look at the registration system before it was struck down, and found its rules to be unusually simple to understand when compared to other aviation rulings, even if it seemed to have little basis in empirical evidence. It bears a resemblance to similar measures in other parts of the world, with its 250 g weight limit for unregistered machines. It will be interesting both from a legal standpoint to see whether any fresh challenges to this zombie law emerge in the courts, and from a technical standpoint to see what advances emerge from Shenzhen as the manufacturers pour all their expertise into a 250 g class of aircraft.

Thanks [ArduinoEnigma] for the tip.

Truly Terrible Dimensioned Drawings

December 14, 2017 by Brian Benchoff 147 Comments

I’m in the planning stages of a side project for Hackaday right now. It’s nothing too impressive, but this is a project that will involve a lot of electromechanical parts. This project is going to need a lot of panel mount 1/8″ jacks and sockets, vertical mount DIN 5 connectors, pots, switches, and other carefully crafted bits of metal. Mouser and Digikey are great for nearly every other type of electrical component, but when it comes to these sorts of electromechanical components, your best move is usually to look at AliExpress or DealExtreme, finding something close to what you need, and buying a few hundred. Is this the best move for a manufacturable product? No, but we’re only building a few hundred of these things.

I have been browsing my usual Internet haunts in the search for the right bits of stamped brass and injection molded plastic for this project, and have come to a remarkable conclusion. Engineers, apparently, have no idea how to dimension drawings. Drafting has been a core competency for engineers from the dawn of time until AutoCAD was invented, and now we’re finally reaping the reward: It’s now rare to find a usable dimensioned drawing on the Internet.

This post is going to be half rant, half explanation of what is wrong with a few of the dimensioned drawings I’ve found recently. Consider this an example of what not to do. There is no reason for the state of engineering drawing to be this bad.

Continue reading “Truly Terrible Dimensioned Drawings” →

ADSL Robustness Verified By Running Over Wet String

December 14, 2017 by Roger Cheng 44 Comments

A core part of the hacker mentality is the desire to test limits: trying out ideas to see if something interesting, informative, and/or entertaining comes out of it. Some employees of Andrews & Arnold (a UK network provider) applied this mentality towards connecting their ADSL test equipment to some unlikely materials. The verdict of experiment: yes, ADSL works over wet string.

ADSL itself is something of an ingenious hack, carrying data over decades-old telephone wires designed only for voice. ADSL accomplished this in part through robust error correction measures keeping the bytes flowing through lines that were not originally designed for ADSL frequencies. The flow of bytes may slow over bad lines, but they will keep moving.

How bad? In this case, a pair of strings dampened with salty water. But there are limits: the same type of string dampened with just plain water was not enough to carry ADSL.

The pictures of the test setup also spoke volumes. They ran the wet string across a space that looked much like every hacker workspace, salt water dripping on the industrial carpet. Experimenting and learning right where you are, using what you have on hand, are hallmarks of hacker resourcefulness. Fancy laboratory not required.

Thanks to [chris] and [Spencer] for the tips.

CNC’d MacBook Breathes Easy

December 14, 2017 by Tom Nardi 65 Comments

Sick of his 2011 Macbook kicking its fans into overdrive every time the temperatures started to climb, [Arthur] decided to go with the nuclear option and cut some ventilation holes into the bottom of the machine’s aluminum case. But it just so happens that he had the patience and proper tools for the job, and the final result looks good enough that you might wonder why Apple didn’t do this to begin with.

After disassembling the machine, [Arthur] used double-sided tape and a block of scrap wood to secure the Macbook’s case to the CNC, and cut out some very slick looking vents over where the internal CPU cooler sits. With the addition of some fine mesh he found on McMaster-Carr, foreign objects (and fingers) are prevented from getting into the Mac and messing up all that Cupertino engineering.

[Arthur] tells us that the internal temperature of his Macbook would hit as high as 102 °C (~215 °F) under load before his modification, which certainly doesn’t sound like something we’d want sitting in our laps. With the addition of his vents however, he’s now seeing an idle temperature of 45 °C to 60 °C, and a max of 82 °C.

In the end, [Arthur] is happy with the results of his modification, but he’d change a few things if he was to do it again. He’s somewhat concerned about the fact that the mesh he used for the grill isn’t non-conductive (he’s using shims of card stock internally to make sure it doesn’t touch anything inside), and he’d prefer the peace of mind of having used epoxy to secure it all together rather than super-glue. That said, it works and hasn’t fallen apart yet; basically the hallmarks of a successful hack.

It’s worth noting that [Arthur] is not the first person to struggle with the Macbook’s propensity for cooking itself alive. A few years back we covered another user who added vents to their Macbook, but not before they were forced to reflow the whole board because some of the solder joints gave up in the heat.