TV Output From Arduino — 1980s Style!

September 11, 2020 by Al Williams 20 Comments

We’ll admit it, we’re all spoiled. A few bucks can now buy a computer that would have been the envy of everyone back in the late 1970s or early 1980s. So it’s no surprise that [krallja] was able to use an old-style video output chip to drive a TV with an Arduino. The TMS9918A is a venerable output device, and if the old computers could drive it then it makes sense that a modern computer could too. You can see a video of the whole experiment, below.

The Internet has also spoiled us, in that it’s dead simple to find datasheets for nearly anything, even these old chips. The only real problem with such aged silicon is that they typically expect a processor with a data and address bus, but most microcontrollers now keep all of that internal. But with enough fast I/O you can simulate a bus just fine. For now, the experiment just cycles through the color output.

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Peripheral Doesn’t Need Deskspace

September 11, 2020 by Brian McEvoy 9 Comments

Some of us are suckers for new hardware. There’s absolutely nothing shameful about a drawer overflowing with gamepads, roll-up keyboards, and those funny-shaped ergonomic mice. MyTeleTouch won’t sate your itch for new hardware because [Dimitar Danailov] didn’t design hardware you hold, because it uses your phone as a catch-all Human Interface Device, HID. A dongle plugs into a standard USB port, and your Android phone can emulate a USB keyboard, mouse, or gamepad over Bluetooth.

Chances are high that you already set up your primary computer with your favorite hardware, but we think we’ve found a practical slant for a minimalist accessory. Remember the last time you booted an obsolete Windows desktop and dug out an old mouse with a questionable USB plug? How long have you poked around the bottom of a moving box trying to find a proprietary wireless keyboard dongle, when you just wanted to type a password on your smart TV? What about RetroPi and a game controller? MyTeleTouch isn’t going to transform your daily experience, but it’ll be there when you don’t want to carry a full-size keyboard down three flights of stairs to press {ENTER} on a machine that spontaneously forgot it has a touch screen. If you don’t have opportunities to play the hero very often, you can choose to play the villain. Hide this in a coworker’s USB port, and while they think you’re sending a text message, you could be fiddling with their cursor.

We enjoy a good prank that everyone can laugh off, and we love little keyboards and this one raises the (space) bar.

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Linux Fu: Literate Regular Expressions

September 11, 2020 by Al Williams 20 Comments

Regular expressions — the things you feed to programs like grep — are a bit like riding a bike. It seems impossible until you learn to do it, and then it’s easy. Part of their bad reputation is because they use a very concise and abbreviated syntax that alarms people. To help people who don’t use regular expressions every day, I created a tool that lets you write them in something a little closer to plain English. Actually, I’ve written several versions of this over the years, but this incarnation that targets grep is the latest. Unlike some previous versions, this time I did it all using Bash.

Those who don’t know regular expressions might freak out when they see something like:

[0-9]{5}(-[0-9]{4})?

How long does it take to figure out what that does? What if you could write that in a more literate way? For example:

digit repeat 5 \

start_group \

   - digit repeat 4 \

end_group optional

Not as fast to type, sure. But you can probably deduce what it does: it reads US Zipcodes.

I’ve found that some of the most popular tools I’ve created over the years are ones that I don’t need myself. I’m sure you’ve had that experience, too. You know how to operate a computer, but you create a menu system for people who don’t and they love it. That’s how it is with this tool. You might not need it, but there’s a good chance you know someone who does. Along the way, the code uses some interesting features of Bash, so even if you don’t want to be verbose with your regular expressions, you might pick up a trick or two.

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Hackaday Podcast 084: Awful Floppy Disk Music, Watching A Robot Climb Walls, A Futuristic Undersea Lab, And Inside A Digital Pregnancy Test

September 11, 2020 by Dan Maloney No comments

With Editor in Chief Mike Szczys off this week, Managing Editor Elliot Williams is joined by Staff Writer Dan Maloney to look over the hacks from the last week. If you’ve ever wondered how the Beatles sound on a floppy disk, wonder no more. Do you fear the coming robopocalypse? This noisy wall-climbing robot will put those fears to rest. We’ll take a look at an undersea lab worthy of the Cousteau name, and finally we’ll look inside a digital pregnancy test and wonder at its unusual power switch.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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Friendly Fiberglassing: Can Hide Glue Replace Epoxy?

September 11, 2020 by Brian McEvoy 40 Comments

Hide glue has been around for thousands of years, and some of it is holding wood pieces three thousand years after application. It is made from animal protein, so vegetarians may want to stick to the petroleum-based adhesives. [Surjan Singh] wanted to see if its longevity made it a contender with modern epoxy by casting a couple of fiberglass car parts with the competing glues. In short, it doesn’t hold up in this situation, but it is not without merit.

Musical instrument makers and antique restorers still buy and use hide glue, but you would never expose it to heat or moisture. To its credit, hide glue doesn’t require a ventilator. All you need is boiling water and a popsicle stick, and you are in business. [Surjan] writes his findings like a narrative rather than steps, so his adventures are a delight to read. He found that a car part made with fiberglass and epoxy will withstand the weather better than the alternative because heat and humidity will soften hide glue. His Saab 96 isn’t the right application, but since it is nearly as strong as epoxy once set, you could make other fabric shapes, like a flannel nightstand or a lace coffee table, and you could shape them in the living room without toxifying yourself

No matter how you want to work with glues and substrates, Bil Herd has you covered, and here is an excellent tip for a cheap degassing setup.

Security This Week: Racoons In My TLS, Bypassing Frontends, And Obscurity

September 11, 2020 by Jonathan Bennett 7 Comments

Raccoon is the next flashy security flaw with a name, cute logo, and a website (and a PDF). Raccoon is a flaw in TLS version prior to 1.3, and seems to be a clever bit of work, albeit one with limited real-world application. The central problem is that these older versions of TLS, when using Diffie Hellman (DH), drop leading all-zero bytes in the resulting pre-master key. As that key is part of the input for calculating the master session key, a shortened pre-master key results in a slightly faster calculation of the master key. If an attacker can make fine-grained timing measurements, he can determine when the pre-master key is trimmed.

Let’s review Diffie Hellman, briefly. The client and server agree on two numeric values, a base g and modulus p, and each party generates a secret key, a and b. Each party calculates a public key by raising the shared base to their own private key, mod the shared modulus: A = g^a mod p. These public keys are exchanged, and each party raises the received key to their own secret key: A^b. Exponents have a non-obvious quirk, the power rule. A value raised to a power raised to a power is the same as the value raised to the power of the exponents multiplied together. g^a^b is equal to g^(a*b). By going through this mathematical dance, the server and client have arrived at a shared value that only they know, while preserving the secrecy of their private keys. Continue reading “Security This Week: Racoons In My TLS, Bypassing Frontends, And Obscurity” →

A Deep Dive Into The Sterzo Steering Plate

September 11, 2020 by Tom Nardi 15 Comments

Pedaling in place isn’t the most exciting pastime, so it’s no surprise that modern technology is being used to make the in-home biking experience a bit more interactive. With a stand on the rear wheel providing resistance, and a movable steering plate under the front to read the handlebar angle, you can now use your standard bike as the “controller” in a virtual environment provided by software such as Zwift.

Paving the way towards a DIY Sterzo clone

[Keith Wakeham] wanted to take a closer look at how Zwift communicated with his Sterzo steering device, and it turned into a pretty epic bout of exploration and reverse engineering. As the video after the break shows, he didn’t just go from sniffing the device’s proprietary Bluetooth Low Energy (BLE) communications protocol to figuring out how to emulate it in software so you could roll your own Zwift peripheral. He also tore the device apart, pulled the firmware from its microcontroller, and postulated how you could build your own low-cost clone device that would work with the existing software.

Even if you have absolutely zero interest in virtual biking, the video [Keith] has put together for this project is really a must watch. Have you ever wanted to sniff and reverse engineer BLE communications? Looking for a real-world example of pulling the firmware off of a consumer device? Maybe in the market for some tips on how to identify unknown ICs on a board? All of that, and quite a bit more, is covered in this nearly hour long hacking tour de force.

On the other hand, if you are interested in adding your own hardware to Zwift, then this look at getting an unsupported stationary bike working with it should be useful.

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