Hackability Matters

January 16, 2021 by Elliot Williams 42 Comments

The Unix Way™ provides extreme hackability. The idea is that software should be written as tools to accomplish discrete tasks, and that it should be modular, extensible, and play well with others. It’s like software as a LEGO set — you can put the blocks together however you want, within limits, and make stuff that’s significantly cooler than any of the individual blocks alone.

Clearly this doesn’t work for all applications — things like graphics editors and web browsers don’t really lend themselves to being elegant tools that integrate well with others, right? It’s only natural that they’re bloaty walled gardens. What happens in the browser must stay in the browser, right?

But how sad is it that the one piece of software you use all day, your window into cyberspace, doesn’t play well with the rest of your system? I’d honestly never really been bothered by that fact until stumbling on TabFS. It’s an extension to Chrome that represents the tabs on your browser as if they were files on your local system — The Unix Way™. And what this means is that any other program that can read from or write to a file can open tabs, collect them, change webpages on the fly, and so on. It opens up the browser to you.

This is tremendously powerful. Don’t like the bookmarking paradigm of your particular browser? Writing your own would be a snap in Python — and you could do cleverer things like apply a little machine learning to handle putting them in categories. Want to pop open (or refresh) a set of webpages at a particular time every day? Cron, or its significantly more complicated counterpart systemd, and a couple lines of code will do that. Want to make a hardware button that converts dark mode to light mode and vice-versa for every website starting with “H”? Can do.

I’m picking on browsers, but many large pieces of software are inaccessible in the same way — even if they’re open source, they don’t open up channels for interaction with user code or scripts. (Everything “in the cloud” or “as a service”, I’m looking at you! But that’s a further rant for another day.) And that’s a shame, because most of these “big” pieces of software actually do the coolest things.

So please, if you’re working on a big software package, or even just writing a plug-in for one, do think about how you can make more of its abilities available to the casual scripter. Otherwise, it’s just plastic blocks that don’t fit with the rest of the set.

Circuit VR: Even More Op Amps

January 15, 2021 by Al Williams 23 Comments

In the last Circuit VR we looked at some basic op amp circuits in a simulator, including the non-inverting amplifier. Sometimes you want an amplifier that inverts the signal. That is a 5V input results in a -5V output (or -10V if the amplifier has a gain of 2). This corresponds to a 180 degree phase shift which can be useful in amplifiers, filters, and other circuits. Let’s take a look at an example circuit simulated with falstad.

Remember the Rules

Last time I mentioned two made up rules that are good shortcuts for analyzing op amp circuits:

The inputs of the op amp don’t connect to anything internally.
The output mysteriously will do what it can to make the inputs equal, as far as it is physically possible.

As a corollary to the second rule, you can easily analyze the circuit shown here by thinking of the negative (inverting) terminal as a virtual ground. It isn’t connected to ground, yet in a properly configured op amp circuit it might as well be at ground potential. Why? Because the + terminal is grounded and rule #2 says the op amp will change conditions to make sure the two terminals are the same. Since it can’t influence the + terminal, it will drive the voltage through the resistor network to ensure the – terminal is at 0V.

Continue reading “Circuit VR: Even More Op Amps” →

Hackaday Podcast 101: Lasering And Milling Absolutely Everything

January 15, 2021 by Mike Szczys 2 Comments

Hackaday editors Mike Szczys and Elliot Williams discuss our favorite hacks of the past week. We accidentally chose a theme, as most of the projects use lasers and are about machining work. We lead off with a really powerful laser that can directly etch circuit boards, only to be later outdone by an even more powerful laser using a chemistry trick to etch glass. We look at how to mix up your own rocket motors, bootstrap your own laser tag, and go down the rabbit hole of building tools for embedded development. The episode wraps up as we discuss what exactly NVMe is and where hardware hacking might take it.

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 (~65 MB)

Places to follow Hackaday podcasts:

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This Week In Security: Ubiquiti, Nissan, Zyxel, And Dovecot

January 15, 2021 by Jonathan Bennett 27 Comments

You may have been one of the many of us who received an email from Ubiquiti this week, recommending a password change. The email stated that there was an unauthorized access of Ubiquiti systems, and while there wasn’t evidence of user data being accessed, there was also not enough evidence to say emphatically that user data was not accessed. Ubiquiti has mentioned that the database that may have been accessed contains a user’s name, email address, hashed password, and optionally the mailing address and phone number.

Depending on how the Ubiquiti authentication system is designed, that hashed password may be enough to log in to someone’s account. In any case, updating your password would invalidate the potentially compromised hash. This event underscores a complaint voiced by Ubiquiti users: Ubiquiti has been making it difficult to administrate hardware without a cloud-enabled account. Continue reading “This Week In Security: Ubiquiti, Nissan, Zyxel, And Dovecot” →

Basics Of Remote Cellular Access: Connecting Via VPN

January 14, 2021 by Lewin Day 9 Comments

You’ve got a machine hooked up to the Internet via a shiny new cellular modem, which you plan to administer remotely. You do a quick check on the external IP, and try and log in from another PC. Try as you might, SSH simply won’t connect. What gives?

The reality of the modern internet is that most clients no longer get their own unique IPv4 address. There simply aren’t enough to go around anymore. Instead, most telecommunications operators use Carrier Grade Network Address Translation which allows a single external address to be shared by many customers. This can get in the way of direct connection attempts from the outside world. Even if that’s not the case, most cellular operators tend to block inbound connections by default. However, there is a way around this quandary – using a VPN. Continue reading “Basics Of Remote Cellular Access: Connecting Via VPN” →

Teardown: Tap Trapper

January 14, 2021 by Tom Nardi 46 Comments

The modern consumer is not overly concerned with their phone conversations being monitored. For one thing, Google and Amazon have done a tremendous job of conditioning them to believe that electronic gadgets listening to their every word isn’t just acceptable, but a near necessity in the 21st century. After all, if there was a better way to turn on the kitchen light than having a recording of your voice uploaded to Amazon so they can run it through their speech analysis software, somebody would have surely thought of it by now.

But perhaps more importantly, there’s a general understanding that the nature of telephony has changed to the point that few outside of three letter agencies can realistically intercept a phone call. Sure we’ve seen the occasional spoofed GSM network pop up at hacker cons, and there’s a troubling number of StingRays floating around out there, but it’s still a far cry from how things were back when folks still used phones that plugged into the wall. In those days, the neighborhood creep needed little more than a pair of wire strippers to listen in on your every word.

Which is precisely why products like the TA-1356 Tap Trapper were made. It was advertised as being able to scan your home’s phone line to alert you when somebody else might be listening in, whether it was a tape recorder spliced in on the pole or somebody in another room lifting the handset. You just had to clip it onto the phone distribution panel and feed it a fresh battery once and awhile.

If the red light came on, you’d know something had changed since the Tap Trapper was installed and calibrated. But how did this futuristic defender of communications privacy work? Let’s open it up and take a look.

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Making A Kid-Friendly Computer As A Present: Or How To Be The Cool Aunt At Christmas

January 13, 2021 by Erin Pinheiro 24 Comments

This article was meant to be finished up before Christmas, so it’ll be a little late whenever you’re reading it to go and prepare this for the holiday. Regardless, if, like me, should you ever be on the lookout for something to give a toddler nephew or relative, it could be worth it to look into your neglected old parts shelves. In my case, what caught my eye was a 9-year-old AMD laptop catching dust that could be better repurposed in the tiny hands of a kid eager to play video games.

The main issues here are finding a decent selection of appropriate games and streamling the whole experience so that it’s easy to use for a not-yet-hacker, all the while keeping the system secure and child-friendly. And doing it all on a budget.

This is a tall order, and requirements will be as individual as children are, of course, but I hope that my experience and considerations will help guide you if you’re in a similar boat.

Continue reading “Making A Kid-Friendly Computer As A Present: Or How To Be The Cool Aunt At Christmas” →