Hiding Data In Music Might Be The Key To Ditching Coffee Shop WiFi Passwords

July 15, 2019 by Daniel Bogdanoff 52 Comments

In a move guaranteed to send audiophiles recoiling back into their sonically pristine caves, two doctoral students at ETH Zurich have come up with an interesting way to embed information into music. What sounds crazy about this is that they’re hiding data firmly in the audible spectrum from 9.8 kHz to 10 kHz. The question is, does it actually sound crazy? Not to our ears, playback remains surprisingly ok.

You can listen to a clip with and without the data on ETH’s site and see for yourself. As a brief example, here’s twelve seconds of the audio presenting two versions of the same clip. The first riff has no data, and the second riff has the encoded data.

You can probably convince yourself that there’s a difference, but it’s negligible. Even if we use a janky bandpass filter over the 8 kHz -10 kHz range to make the differences stand out, it’s not easy to differentiate what you’re hearing:

After many years of performing live music and dabbling in the recording studio, I’d describe the data-encoded clip as having a tinny feedback or a weird reverb effect. However, you wouldn’t notice this in a track playing on the grocery store’s speaker. Continue reading “Hiding Data In Music Might Be The Key To Ditching Coffee Shop WiFi Passwords” →

Homekit Compatible Sonoff Firmware Without A Bridge

July 14, 2019 by Tom Nardi 38 Comments

Generally speaking, home automation isn’t as cheap or as easy as most people would like. There are too many incompatible protocols, and more often than not, getting everything talking requires you to begrudgingly sign up for some “cloud” service that you didn’t ask for. If you’re an Apple aficionado, there can be even more hoops to jump through; getting your unsupported smart home devices working with that Cupertino designed ecosystem often involves running your own HomeKit bridge.

To try and simplify things, [Michele Gruppioni] has developed a firmware for the ubiquitous Sonoff WIFI Smart Switch that allows it to speak native HomeKit. No more using a Raspberry Pi to act as a mediator between your fancy Apple hardware and that stack of $4 Sonoff’s from AliExpress, they can now talk to each other directly. In the video after the break you can see that the iPad identifies the switch as unofficial device, but since it’s compliant with the HomeKit API, that doesn’t prevent them from talking to each other.

Not only will this MIT licensed firmware get your Sonoff Basic, Sonoff Slampher, or Sonoff S26 talking with your Apple gadgets, but it also provides a web interface and REST API so it retains compatibility with whatever else you might be running in your home automation setup. So while the more pedestrian users of your system might be turning the porch light on with their iPhones, you can still fire it up with a Bash script as nature intended.

Of course, if you don’t mind adding a Raspberry Pi bridge to the growing collection of devices on your network, we’ve got plenty of other HomeKit-enabled projects for you to take a look at.

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The Physics Behind Antennas

July 11, 2019 by Al Williams 34 Comments

If you have done any sort of radio work you probably have a fair idea about what antennas do. It is pretty easy to have a cursory understanding of them, too. You probably know there’s something magic about antennas that are a quarter wave long or a half wave long and other multiples. But do you know why that matters? Do you understand the physics of why wire in a special configuration will cause signals to propagate through space? [Learn Engineering] does, and their new video is one of the best graphical explanations of what’s really going on in an antenna that we’ve seen. You can watch the video below.

If you tackle antennas using math, it is a long discussion. However, this video is about 8 minutes long and uses some great graphics to show how moving charges can produce a propagating electromagnetic field.

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New Part Day: The $15 ESP32 With Cellular

July 9, 2019 by Brian Benchoff 51 Comments

Cruise around AliExpress for long enough and you’ll find some interesting new hardware. The latest is the TTGO T-Call, an ESP32 breakout board that also has a cellular modem. Yes, it’s only a 2G modem, but that still works in a lot of places, and the whole thing is $15.

On board the TTGO T-Cal is the ESP-WROVER-B, the same module you all know and love that features a dual-core ESP running at 240 MHz with 4 MB of Flash and 8 MB of SRAM. Add to this WiFi and Bluetooth, and you have a capable microcontroller platform. Of note is that this board includes a USB-C port, ostensibly wired so that it behaves like a normal USB micro port. That’s neat, 2019 is the year USB C connectors became cheaper than USB micro connectors.

In addition to the ESP32 module, there’s also cellular in the form of a SIM800 module. This module has been around for a while and used in many, many cellular-connected projects and products like the ZeroPhone. This module is only a 2G module, and that’ll be going away shortly (if not already) in built-up areas, but this can serve as a building block for modules that have more Gees than a 2G module. That said, if you’re looking for a WiFi and cellular bridge for fifteen bucks, you could do a lot worse for a lot more money.

Amiga In The MiST Gets Online With An ESP8266

July 3, 2019 by Tom Nardi 9 Comments

While he couldn’t quite come up with the cash to buy one in their hayday, [Bruno Antunes] has always been fascinated with the Amiga. When PCs got fast enough he used emulators like UAE to get a taste of the experience, but it was never quite the same thing. Not until he found the MiST anyway, which uses an FPGA to implement several retro computers such as the Apple II, Atari, and of course his beloved Amiga.

The only downside for [Bruno] was that the MiST has no network interfaces. To get onto the Internet, he had to install an ESP8266 inside the device and spend some quality time tweaking various software settings to get everything talking to each other. The end result is a BBS hosted on an Amiga 1200, that’s running on an FPGA, that’s connected to WiFi via an ESP8266. What a time to be alive.

Adding the ESP8266 to the MiST was actually quite straightforward, as there’s an unpopulated serial port header right on the board. Though [Bruno] cautions this header has been removed as of version 1.4 of the device, so if you’re in the market for an FPGA retro box and might want to get it online at some point, that may be a detail to keep in mind. The ESP is running a firmware which implements Serial Line IP (SLIP); which allows you to use TCP/IP over a serial port, albeit very slowly.

The hardware implant went well enough, but unfortunately [Bruno] found the ESP8266 was unable to communicate through the thick metal case of the MiST. He enlisted his girlfriend to make a new papercraft enclosure for the MiST that the ESP could talk though, and it even has the added benefit of glowing thanks to the internal LEDs. We probably would have just got one of the ESP modules that includes an external antenna, but to each their own.

With the hardware taken care of, the rest of the considerable write-up details how he got the Amiga operating system to talk to the Internet through the SLIP connection. He goes over everything from setting the system time with NTP to getting a Telnet daemon installed. As you might expect, this involves installing a number of additional software packages, but [Bruno] is kind enough to provide links for everything you’ll need.

We’ve seen the ESP8266 used to get other retro computers onto the modern Internet before, but it’s usually through the use of an external device. This internal modification is very clean, and seems like a no-brainer for anyone who owns a MiST and a soldering iron.

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Smart Bike Helmet Is Wireless

June 26, 2019 by Al Williams 16 Comments

If you ride a bike, you probably share the road with a lot of cars. Unfortunately, they don’t always share the road very well with you. [Mech Tools] took a helmet, a few Arduinos, and some wireless transceivers and made headgear that shows when you stop and also shows turn signals. We were a little surprised, though, that the bike in question looks like a motorcycle. In most countries, motorcycle helmets meet strict safety standards and modifying them is probably not a good idea. However, it wasn’t exactly clear how the extra gear attached to the helmet, so it is hard to say if the project is very practical or not.

In particular, it looks as though the first version had the electronics just stuck to the outside of the helmet. The final one had things mounted internally and almost certainly had cuts or holes made for the lights. We aren’t sure which of those would be more likely to be a problem in the case of an accident.

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Storm Chasers Score Bullseye On Tornado With Instrument-Packed Rocket

June 5, 2019 by Dan Maloney 16 Comments

Model rockets are a heck of a lot of fun, and not a few careers in science and engineering were jump-started by the thrilling woosh and rotten-egg stench of an Estes rocket launch. Adding simple instrumentation to the rocket doubles the fun by allowing telemetry to be sent back, or perhaps aiding in recovery of a lost rocket. Sending an instrument-laden rocket into a tornado is quite a few notches past either of those scenarios, and makes them look downright boring by comparison.

A first and hopefully obvious point: just don’t do this. [ChasinSpin] and [ReedTimmer] are experienced storm chasers, and have a small fleet of purpose-built armored vehicles at their disposal. One such vehicle, the Dominator, served as a mobile launch pad for their rocket as they along with [Sean Schofer] and [Aaron Jayjack] chased what developed into an EF4 monster tornado near Lawrence, Kansas on May 28. They managed to score a direct hit on the developing tornado, only 100 feet (30 meters) away at the time, and which took the rocket to 35,000 ft (10.6 km) and dragged it almost 30 miles (42 km) downrange. They lost touch with it but miraculously recovered it from a church parking lot.

They don’t offer a lot of detail on the rocket itself, but honestly it looks pretty much off-the-shelf, albeit launched from an aimable launchpad. [ChasinSpin] does offer a few details on the instrument package, though – a custom PCB with GPS, IMU, a temperature/humidity/barometric pressure sensor, and a LoRa link to send a data packet back every second. The card also supported an SD card for high-resolution measurements at 10 times per second. Check out the launch in the video below, and be sure to mouse around to get a look at the chaotic environment they were working in.

Even if this isn’t as cool as sending a sounding rocket into an aurora, it’s still really cool. We’re looking forward to seeing what kind of data this experiment collected, and what it reveals about the inner workings of these powerful storms.

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