Hacking A USB Port Onto An Old Router

January 26, 2016 by 25 Comments

Sometimes hacks don’t have to be innovative to be satisfying. We thought that [daffy]’s instructions and video (embedded below the break) for turning an old WRT54G router into an Internet radio were worth a look even if he’s following a well-traveled path and one that we’ve reported on way back when.

The hack itself is simple. [daffy] locates unused USB data lines, adds in a 5V voltage regulator to supply USB bus power, and then connects it all to a USB sound card. Hardware side, done! And while he doesn’t cover the software side of things in this first video, we know where he’s headed.

The WRT54G router was the first commodity Linux-based router to be extensively hacked, and have open-source firmware written for it. If you’re using OpenWRT or dd-wrt on any of your devices, you owe a debt to the early rootability of the WRT54G. Anyway, it’s a good bet that [daffy] is going to find software support for his USB sound card, but we remain in suspense to see just exactly how the details pan out.

Our favorite WRT54G hack is still an oldie: turning a WRT54G into the brains for a robot. But that was eight years ago now, so surely there’s something newer and shinier. What’s the coolest device that you’ve seen a WRT router hacked into?

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The Best Projects That Fit In A Square Inch

January 13, 2016 by 45 Comments

A few years ago, we started Hackaday.io as a project hosting site for The People Who Actually Make Stuff™, and since then we’ve been amazed by what the community can put together. We have well over 100,000 hackers on board in an awesome community. Sometime around September, a few members of the Hackaday.io community decided to follow in the footsteps of the very successful contests we’ve had on Hackaday.io. This led to the Square Inch Contest, a challenge to put the coolest electronics inside a square inch PCB. An inch the distance light travels in 1/11802852665.12644 of a second for those of you without freedom units.

quad
The winner, Quadcopter In One Inch

With almost eighty entries, the judges had a very difficult task ahead of them. In the end, only one project would be the best. The winner of Hackaday.io’s first user-created contest is Quadcopter In One Inch from [jeff]. This wins the grand prize of a $100 credit for the Hackaday Store and a $50 gift certificate to OSHPark.

There are six other prizes, each receiving a $50 credit to the Hackaday Store and $25 for OSHPark:

Winners

The judges for the Square Inch Project would like to give an honorable mention to Twiz and the blinktronicator. The judges would also like to express amazement in how much work actually goes into judging a contest on Hackaday.io. Spending a few weeks working on the judging for a contest with eighty entries imbues a sort of respect for people who can judge a contest with one thousand entries in three days, as the Hackaday crew has done with two Hackaday Prizes so far. While they were doing that, I was sitting back and cracking jokes about Fleiss’ Kappa.

This was the first community-created contest on Hackaday.io, but it is surely not the last. We don’t know what the next contest will be – that will be up to someone on Hackaday.io – but there will be one, and like the Square Inch Project, it will be awesome.

Messages From Hell: Human Signal Processing

December 30, 2015 by 54 Comments

Despite the title, there’s no religious content in this post. The Hell in question is the German inventor [Rudolph Hell]. Although he had an impressive career, what most people remember him for is the Hellschreiber–a device I often mention when I’m trying to illustrate engineering elegance. What’s a Hellschreiber? And why is it elegant?

The first question is easy to answer: the Hellschreiber is almost like a teletype machine. It sends printed messages over the radio, but it works differently than conventional teletype. That’s where the elegance comes into play. To understand how, though, you need a little background.

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Biometric Bracelet Electrifies You To Unlock Your Tablet

December 8, 2015 by 3 Comments

Researchers [Christian Holz] and [Marius Knaust] have come up with a cool new way to authenticate you to virtually any touchscreen device. This clever idea couples a biometric sensor and low-data-rate transmitter in a wearable wrist strap that talks to the touch screen by electrifying you.

Specifically the strap has electrodes that couple a 50V, 150kHz signal through your finger, to the touchscreen. The touchscreen picks up both your finger’s location through normal capacitive-sensing methods and the background signal that’s transmitted by the “watch”. This background signal is modulated on and off, transmitting your biometric data.

The biometric data itself is the impedance through your wrist from one electrode to another. With multiple electrodes encircling your wrist, they end up with something like a CAT scan of your wrist’s resistance. Apparently this is unique enough to be used as a biometric identifier. (We’re surprised.)

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Audio Effects On The Intel Edison

December 2, 2015 by 15 Comments

With the ability to run a full Linux operating system, the Intel Edison board has more than enough computing power for real-time digital audio processing. [Navin] used the Atom based module to build Effecter: a digital effects processor.

Effecter is written in C, and makes use of two libraries. The MRAA library from Intel provides an API for accessing the I/O ports on the Edison module. PortAudio is the library used for capturing and playing back audio samples.

F9GW4Y4IGQFYP23.MEDIUMTo allow for audio input and output, a sound card is needed. A cheap USB sound card takes care of this, since the Edison does not have built-in hardware for audio. The Edison itself is mounted on the Edison Arduino Breakout Board, and combined with a Grove shield from Seeed. Using the Grove system, a button, potentiometer, and LCD were added for control.

The code is available on Github, and is pretty easy to follow. PortAudio calls the audioCallback function in effecter.cc when it needs samples to play. This function takes samples from the input buffer, runs them through an effect’s function, and spits the resulting samples into the output buffer. All of the effect code can be found in the ‘effects’ folder.

You can check out a demo Effecter applying effects to a keyboard after the break. If you want to build your own, an Instructable gives all the steps.

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Your First GNU Radio Receiver With SDRPlay

November 12, 2015 by 25 Comments

Although GRC (the GNU Radio Companion) uses the word radio, it is really a graphical tool for building DSP applications. In the last post, I showed you how you could experiment with it just by using a sound card (or even less). However, who can resist the lure of building an actual radio by dragging blocks around on a computer screen?

For this post and the accompanying video, I used an SDRPlay. This little black box has an antenna jack on one end and a USB port on the other. You can ask it to give you data about a certain area of the RF spectrum and it will send complex (IQ) data out in a form that GRC (or other DSP tools) can process.

The SDRPlay is a great deal (about $150) but if you don’t want to invest in one there are other options. Some are about the same price (like the HackRF or AirSpy) and have different features. However, you can also use cheap TV dongles, with some limitations. The repurposed dongles are not as sensitive and won’t work at lower frequencies without some external help. On the other hand, they are dirt cheap, so you can overlook a few little wrinkles. You just can’t expect the performance you’ll get out of a more expensive SDR box. Some people add amplifiers and converters to overcome these problems, but at some point it would be more cost effective to just spring for a more expensive converter.

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Getting Started With GNU Radio

November 11, 2015 by 25 Comments

Software Defined Radio (SDR)–the ability to process radio signals using software instead of electronics–is undeniably fascinating. However, there is a big gap from being able to use off-the-shelf SDR software and writing your own. After all, SDRs require lots of digital signal processing (DSP) at high speeds.

Not many people could build a modern PC from scratch, but nearly anyone can get a motherboard, some I/O cards, a power supply, and a case and put together a custom system. That’s the idea behind GNU Radio and SDR. GNU Radio provides a wealth of Python functions that you can use to create sophisticated SDR application (or, indeed, any DSP application).

If Python is still not up your alley (or even if it is), there’s an even easier way to use GNU Radio: The GNU Radio Companion (GRC). This is a mostly graphical approach, allowing you to thread together modules graphically and build simple GUIs to control you new radio.

Even though you usually think of GRC as being about radios, it is actually a good framework for building any kind of DSP application, and that’s what I’ll show you in the video below. GRC has a signal generator block and interfaces to your sound card. It even has the ability to read and write data to the file system, so you can use it to do many DSP applications or simulations with no additional hardware.

UPDATE: Don’t miss the follow-up post that uses SDRPlay to build a GNU Radio based receiver.

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