There’s an old saying, that you should do everything at least twice. Once to learn how to do it, and then a second time to do it right. Perhaps [Zweben] would agree, since he wasn’t satisfied with his first Neopixel clock and proceeded to build another one. One lesson learned: soldering 180 tiny solder joints isn’t much fun. This time, [Zweben] set out to make a printed circuit board and redesign the clock to make it easier to assemble.
The clock uses multiple copies of a single circuit board. The board holds Neopixel strips in a 7-segment arrangement. Each board can also hold all of the electronics needed to drive the clock. Only the first board gets the microcontroller and other circuits.
There’s a lot more to learning how to play the guitar than just playing the right notes at the right time and in the right order. To produce any sound at all requires learning how to do completely different things with your hands simultaneously, unless maybe you’re a direct descendant of Eddie Van Halen and thus born to do hammer ons. There’s a bunch of other stuff that comes with the territory, like stringing the thing, tuning it, and storing it properly, all of which can be frustrating and discouraging to new players. Add in the calluses, and it’s no wonder people like Guitar Hero so much.
The future of humans is on Mars. Between SpaceX, Boeing, NASA, and every other national space program, we’re going to Mars. With this comes a problem: flying to Mars is relatively easy, but landing a large payload on the surface of another planet is orders of magnitude more difficult. Mars, in particular, is tricky: it has just enough atmosphere that you need to design around it, but not enough where we can use only parachutes to bring several tons down to the surface. On top of this, we’ll need to land our habitats and Tesla Roadsters inside a very small landing ellipse. Landing on Mars is hard and the brightest minds are working on it.
At this year’s Hackaday Superconference, we learned how hard landing on Mars is from Ara Kourchians (you may know him as [Arko]) and Steve Collins, engineers at the Jet Propulsion Laboratory in beautiful Pasadena. For the last few years, they’ve been working on COBALT, a technology demonstrator on how to use machine vision, fancy IMUs, and a host of sensors to land autonomously on alien worlds. You can check out the video of their Supercon talk below.
Previously, we discussed how to apply the most basic hypothesis test: the z-test. It requires a relatively large sample size, and might be appreciated less by hackers searching for truth on a tight budget of time and money.
As an alternative, we briefly mentioned the t-test. The basic procedure still applies: form hypotheses, sample data, check your assumptions, and perform the test. This time though, we’ll run the test with real data from IoT sensors, and programmatically rather than by hand.
The most important difference between the z-test and the t-test is that the t-test uses a different probability distribution. It is called the ‘t-distribution’, and is similar in principle to the normal distribution used by the z-test, but was developed by studying the properties of small sample sizes. The precise shape of the distribution depends on your sample size. Continue reading “Statistics And Hacking: A Stout Little Distribution”→
The 555 timer is one of that special club of integrated circuits that has achieved silicon immortality. Despite its advanced age and having had its functionality replicated and superceded in almost every way, it remains in production and is still extremely popular because it’s simply so useful. If you are of A Certain Age a 555 might well have been the first integrated circuit you touched, and in turn there is a very good chance that your project with it would have been a simple electric organ.
If you’d like to relive that project, perhaps [Alexander Ryzhkov] has the answer with his 555 piano. It’s an entry in our coin cell challenge, and thus uses a CMOS low voltage 555 rather than the power-hungry original, but it’s every bit the classic 555 oscillator with a switchable resistor ladder you know and love.
Physically the piano is a tiny PCB with surface-mount components and physical buttons rather than the stylus organs of yore, but as you can see in the video below the break it remains playable. We said it was tiny, but some might also use tinny.
Years ago, while the GPLv3 was still being drafted, I got a chance to attend a presentation by Richard Stallman. He did his whole routine as St IGNUcius, and then at the end said he would be answering questions in a separate room off to the side. While the more causal nerds shuffled out of the presentation room, I went along with a small group of free software aficionados that followed our patron saint into the inner sanctum.
When my turn came to address the free software maestro, I asked what advantages the GPLv3 would have to a lowly hacker like myself? I was familiar with the clause about “Tivoization“, the idea that any device running GPLv3 code from the manufacturer should allow the user to be able to install their own software on it, but this didn’t seem like the kind of thing most individuals would ever need to worry about. Was there something in the new version of the GPL that would make it worth adopting in personal or hobby projects?
Yes, he really dresses up like this.
Interestingly, a few years after this a GPLv2 program of mine was picked up by a manufacturer and included in one of their products (never underestimate yourself, folks). So the Tivoization clause was actually something that did apply to me in the end, but that’s not the point of this story.
Mr. Stallman responded that he believed the biggest improvement GPLv3 made over v2 for the hobbyist programmer was the idea of “forgiveness” in terms of licensing compliance. Rather than take a hard line approach like the existing version of the GPL, the new version would have grace periods for license compliance. In this way, legitimate mistakes or misunderstandings of the requirements of the GPL could be resolved more easily.
Believe it or not, there are quite a few people out there who have purchased gun safes that can be remotely unlocked by Bluetooth. Now we can understand why somebody might think this was a good idea: the convenience of being able to hit a button on your phone and have your weapon available in the heat of the moment is arguably a big selling point for people who are purchasing something like this for home defense. But those with a more technical mind will likely wonder if the inherent risks of having your firearm (or other valuables) protected by a protocol that often relies on security by obscurity outweighs the convenience of not needing to enter in a combination on the keypad.
[Two Six Labs] has not publicly released the complete source code of the software demonstrated in their YouTube video for very obvious reasons, but the page on their site does go into fantastic detail on how they uncovered the multiple vulnerabilities that allowed them to write it. Even if you’re not the kind of person who would ever need a gun safe, the information contained in their documentation about analyzing Bluetooth communications is fascinating reading.
It was discovered that the PIN for the safe was actually being transmitted by the accompanying smartphone application in plain-text, which would be bad enough normally. But after further analysis, it became clear that the safe wasn’t even bothering to check the PIN code anyway.
Scripting app interactions with ADB and Python
For extra style points, [Two Six Labs] also show a way to brute force the PIN using the Vaultek Android application by writing a Python script that punches in codes sequentially until it hits on the right one; the developers didn’t even bother to put in limits on failed attempts.
For a device that is ostensibly designed to contain a deadly weapon, the security flaws the team at [Two Six Labs] discovered are absolutely inexcusable. But there is a positive outcome, as the manufacturer has vowed to update the vulnerable safes and make a better effort in the future to more rigorously design and test their Bluetooth implementation. This is the goal of responsible disclosure, and we’re encouraged to see the manufacturer doing the right thing
