Open-Source Parametric CAD in Your Browser

Until recently, computer-aided design (CAD) software was really only used by engineering companies who could afford to pay thousands of dollars a year per license. The available software, while very powerful, had a very high learning curve and took a lot of training and experience to master. But, with the rise of hobbyist 3D printing, a number of much more simple CAD programs became available.

While these programs certainly helped makers get into 3D modeling, most had serious limitations. Only a few have been truly open-source, and even fewer have been both open-source and parametric. Parametric CAD allows you to create 3D models based on a series of parameters, such as defining a cube by its origin and dimensions. This is in contrast to sculpting style 3D modeling software, which is controlled much more visually. The benefit of parametric modeling is that parameters can be changed later, and the model can be updated on the fly. Features can also be defined mathematically, so that they change in relation to each other.

While still in its infancy, JS.Sketcher is seeking to fill that niche. It is 100% open-source, runs in your browser using only JavaScript, and is fully parametric (with both constraints and editable dimensions). At this time, available features are still pretty limited and simple. You can: extrude/cut, revolve, shell, and do boolean operations with solids. More advanced features aren’t available yet, but hopefully will be added in the future.

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Web Matrix Control Proves Power of ESP8266

LED matrix projects are all over the place, but this one is interesting for its simplicity: it’s an LED matrix that is driven straight from an ESP8266 board. [Ray] put it together as a quick project for his students to teach the basics of LED programming.

It’s built using a WS2812 LED matrix board he designed himself and his own ESPToy ESP8266 dev board. But the gist of the hardware is simply an ESP8266 and some WS2812’s. Where this gets interesting is with the user interaction side of things. The ESP makes WiFi and web serving easy, and [Ray] has build a simple HTTP GET API into the firmware. This is a great combination for the web dashboard and JavaScript-based animation programs [Ray] is demonstrating in the video below.

Just get on the same network and load up the module’s WiFi address for a graphical representation of the 5×7 LED matrix. Pick a color, turn pixels on or off, or choose a predefined pattern and send it to the hardware. This is a powerful way to get use input and with this as a guide it’s fast to set up for pretty much an application you can think of. Just work your way through the documents he put together for the workshop (Zip file link), including all of the code and the slides he used to run the workshop.

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Running LISP on an ESP8266

LISP is a polarizing language. Either you love it or you hate it. But we’ll put aside our personal preferences to bring you a good hack. In this case a LISP environment running on an ESP8266. [Dmitry] is on the “love it” side of the fence — he’s been waiting for an excuse to code up a LISP interpreter for a while, and he found one in the ESP8266.

there-is-always-a-way-2Actually, [Dmitry] is running LISP inside JavaScript, which is itself presumably coded up in C, before it’s assembled to run on an ESP8266. (It’s turtles all the way down!) This means that he can piggy-back on JavaScript’s garbage collection and console handling and so on. After picking a suitably small LISP implementation (actually a Scheme dialect for those of you who know the difference), he went to work.

One weekend bled into the next, but he got the system running, connected to the network, and had LEDs blinking! In the end, he even managed to squeeze in some optimization for memory’s sake. Pretty cool, and because it takes advantage of an already complete system, it can even be made pretty useful. Not bad for a few weekends’ work!

And finally, if Lots of Irritating Silly Parentheses is your idea of a good time, but the wealth of computing resources available on an ESP8266 seem overkill, have a look at Microlisp, running on an AVR. Or go to the opposite extreme, and run a LISP OS on a Raspberry Pi. Whatever you do, don’t forget to close your parentheses! (We’re told that’s a traditional LISPer farewell.)

Orka Controls the (Pi) World

If you deploy a lot of Raspberry Pi computers, you might find it inconvenient to log into each one to perform different tasks. Orka, an open source project by [Karthik K], is a server that runs on a desktop PC (Windows, Linux, or Mac) and can control multiple Orka clients (that can run on a Pi, or a desktop PC). We understand that [Karthik K] is looking for Mac testers, by the way.

From the server, you can execute commands and create tasks. You can also receive notification when a client PC reaches a threshold (for example, over temperature or too much CPU or RAM usage). You can open a shell on a client and do other operations.

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LastPass Happily Forfeits Passwords to Simple Javascript

Lastpass is a great piece of software when it comes to convenience, but a recent simple hack shows just how insecure software like it can be. [Mathias Karlsson] nabbed a nice $1000 bounty for its discovery.

Lastpass’s auto-fill works by injecting some html into the website you’re visiting. It runs a bit of Javascript to parse the URL. However, the parsing script was laughably vague. By changing the URL of the page, inserting a few meaningless-to-the server slugs into the URL, an attacker could get Lastpass to give it a password and username combo for any website.

The discussion in the HackerNews comment section more-or-less unilaterally agreed that most systems like this have their glaring flaws, but that the overall benefits of having secure passwords generated and managed by software was still worth the risk when compared to having a few commonly reused passwords over multiple sites.

One could get a more secure key manager by using software like KeePass, but it’s missing some of the convenience factor of remote-based services and relies on a user protecting their key files adequately.

Still, as scary as they are, openly discussing hacks like this after responsible disclosure is good because they force companies like Lastpass, who have some very big name clients, to take their code review and transparency more seriously.

Very Clever 555 Bassline Synth/Sequencer

If we had a dime for every 555-based noisemaker circuit we see… But this one’s got a twist.

[Tristan] does two things that elevate his sawtooth-wave noisemaker above the norm. First, he gets a clean sawtooth wave out of it so that it sounds about right. Then he manages to make it more or less playable. It’s a refined version of a classic hack.

555sawtoothosc2

The first trick is a matter of putting a constant current supply upstream of the timing capacitor. The usual 555-timer circuit just charges the capacitor up from the power rails through a resistor. This is fine if all you care about is timing. But because the current is proportional to the constantly dropping voltage difference, the voltage on the capacitor is an exponential function over time.

A simple transistor current source linearizes the waveform in no time. Raw sawtooth waves are “rich in harmonics” which is synth-geek code for “a bit grating”, but it will surely do well with a little filtering. The Javascript suggests that he’s already thinking in that direction, but we’re going to need video proof!

The second cool trick up [Tristan]’s sleeve is the light-dependent resistor (LDR) that determines the pitch. Yeah, we’ve all made those before — the light-dependent “Theremin”. But [Tristan] took the extra step and wrote up a Javascript application that makes his monitor brighter and darker, enabling him to get musical pitches out of the gizmo.

We’ve always wanted to implement LED-to-LDR control while writing the Logic Noise series, but never found a reliable way to make it work. It’s cool to see [Tristan]’s efforts. Maybe we’ll pull a 555 out of the junk box in his honor.

Forty-Year-Old Arcade Game Reveals Secrets of Robot Path Planning

What’s to be gained from reverse engineering a four-decade-old video game? As it turns out, quite a lot, and as you’ll learn from [Norbert]’s recent talk at the ViennaJS meetup, it’s not just about bringing a classic back to life.

The game in question is Kee Game’s Sprint 2, a monochrome 2D car race that allowed two players to compete head to head. The glorious Harvest Gold and Burnt Orange color scheme just screams 1970s, and it might be hard to see why this game was once a popular quarter-eater. But it was quite engaging for the day, and [Norbert] was interested in reverse engineering it. That he did, using JavaScript to build a faithful browser-based emulation of the game. And he took it further, creating a 3D first-person version of the game.

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