Hackaday Podcast Ep3 – Igloos, Lidar, And The Blinking LED Of RF Hacking

It’s cold outside! So grab a copy of the Hackaday Podcast, and catch up on what you missed this week.

Highlights include a dip into audio processing with sox and FFMPEG, scripting for Gmail, weaving your own carbon fiber tubes, staring into the sharpest color CRT ever, and unlocking the secrets of cheap 433 MHz devices. Plus Elliot talks about his follies in building an igloo while Mike marvels at what’s coming out of passive RFID sensor research.

And what’s that strange noise at the end of the podcast?

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Don’t Look Now, But Your Necklace is Listening

There was a time when the average person was worried about the government or big corporations listening in on their every word. It was a quaint era, full of whimsy and superstition. Today, a good deal of us are paying for the privilege to have constantly listening microphones in multiple rooms of our house, largely so we can avoid having to use our hands to turn the lights on and off. Amazing what a couple years and a strong advertising push can do.

So if we’re going to be funneling everything we say to one or more of our corporate overlords anyway, why not make it fun? For example, check out this speech-to-image necklace developed by [Stephanie Nemeth]. As you speak, the necklace listens in and finds (usually) relevant images to display. Conceptually this could be used as an assistive communication technology, but we’re cool with it being a meme display device for now.

Hardware wise, the necklace is just a Raspberry Pi 3, a USB microphone, and a¬†HyperPixel 4.0 touch screen. The Pi Zero would arguably be the better choice for hanging around your neck, but [Stephanie] notes that there’s some compatibility issues with Node.js on the Zero’s ARM6 processor. She details a workaround, but says there’s no guarantee it will work with her code.

The JavaScript software records audio from the microphone with SoX, and then runs that through the Google Cloud Speech-to-Text service to figure out what the wearer is saying. Finally it does a Google image search on the captured words using the custom search JSON API to find pictures to show on the display. There’s a user-supplied list of words to ignore so it doesn’t try looking up images for function words (such as “and” or “however”), though presumably it can also be used to blacklist certain imagery you might not want popping up on your chest in mixed company.

We’d be interested in seeing somebody implement this software on a Raspberry Pi powered digital frame to display artwork that changes based on what the people in the room are talking about. Like in¬†Antitrust, but without Tim Robbins offing anyone.

[Thanks to DarkSim905 for the tip.]

Shell Script Synthesizer Knocks Your SoX Off

Sound eXchange, or SoX, the “Swiss Army knife of audio manipulation” has been around for as long as the Linux kernel, and in case you’re not familiar with it, is a command line tool to play, record, edit, generate, and process audio files. [porkostomus] was especially interested about the generating part, and wrote a little shell script that utilizes SoX’s built-in synthesizer to compose 8-bit style music.

The script comes with a simple yet straightforward user interface to record the lead and bass parts into a text file, and play them back later on. Notes from C2 to C5 are currently supported, and are mapped to the keyboard in a two-row piano layout. The output file format itself is just a plain text listing of the played note, wave form, and note length. This lets you easily edit the song or even generate it from an alternative source, for example MIDI. Also note that there are no initial audio files required here, SoX will generate them as needed.

Admittedly, the command line interface may not be the most convenient way to create music, but nevertheless, it is a way — and that is [porkostomus]’s main mission here. Also, SoX is fun — and versatile, you can apply its audio effects even on images, or decode strange signals sent from a helicopter with it.

Command line video processing using FOSS

[Daniel Paluska] is getting away from the point-and-click by editing videos from the command line. Using the free open source software packages FFmpeg, Imagemagick, and Sox he produces new clips from multiple videos with effects like overlaying, slicing, and assigning each video to a different quadrant. The last option would be useful for displaying different angled shots of the same thing all at once but we’re sure you can find a way to use them all. He is using shell scripts to automate some of the process but the commands are still easy enough to understand if this is your first foray into these tools. After all, great video production will go a long way toward becoming an Internet sensation.