Otters Deliver A High Power Stationary Audio Experience

Our favorite raft of otters is back at it again with another display of open source audio prowess as they bring us the OtterCastAmp, the newest member of the OtterCast family of open source audio multitools. If you looked at the previous entry in the series – the OtterCastAudio – and thought it was nice but lacking in the pixel count or output power departments then this is the device for you.

The Amp is fundamentally a very similar device to the OtterCastAudio. It shares the same Allwinner S3 Cortex-A application processor and runs the same embedded Linux build assembled with Buildroot. In turn it offers the same substantial set of features and audio protocol support. It can be targeted by Snapcast, Spotify Connect or AirPlay if those are your tools of choice, or act as a generic PulseAudio sink for your Linux audio needs. And there’s still a separate line in so it source audio as well.

One look at the chassis and it’s clear that unlike the OtterCastAudio this is not a simple Chromecast Audio replacement. The face of the OtterCastAmp is graced by a luscious 340×800 LCD for all the cover art your listening ear can enjoy. And the raft of connectors in the back (and mountain of inductors on the PCBA) make it clear that this is a fully fledged class D amplifier, driving up to 120W of power across four channels. Though it may drive a theoretical 30W or 60W peak across its various outputs, with a maximum supply power of 100W (via USB-C power delivery, naturally) the true maximum output will be a little lower. Rounding out the feature set is an Ethernet jack and some wonderfully designed copper PCB otters to enjoy inside and out.

As before, it looks like this design is very close to ready for prime time but not quite there yet, so order at your own risk. Full fab files and some hints are linked in the repo mentioned above. If home fabrication is a little much it looks like there might be a small manufacturing run of these devices coming soon.

You Otter Be Able To Stream That Audio: Open Hardware Eclipses Chromecast Audio

When Google halted production of the Chromecast Audio at the start of 2019, there was a (now silent) outcry. Fans of the device loved the single purpose audio streaming dongle that delivered wide compatibility and drop-dead simplicity at a rock bottom $35 price. For evidence of this, look no further than your favorite auction site where they now sell for significantly more than they did new, if you can even find an active listing. What’s a prolific hacker to do about this clear case of corporate malice? Why, reinvent it of course! And thus the Otter Cast Audio V2 was born, another high quality otter themed hack from one of our favorite teams of hardware magicians [Niklas Fauth, Jan Henrik, Toble Miner, and Manawyrm].

USB-C and Ethernet, oh my!

The Otter Cast Audio is a disc about the shape and size of standard Chromecast (about 50mm in diameter) and delivers a nearly complete superset of the original Chromecast Audio’s features plus the addition of a line in port to redirect audio from existing devices. Protocol support is more flexible than the original, with AirPlay, a web interface, Spotify Connect, Snapcast, and even a PulseAudio sink to get your Linux flavored audio bits flowing. Ironically the one thing the Otter Cast Audio doesn’t do is act as a target to Cast to. [Jan] notes that out of all the protocols supported here, actual Cast support was locked down enough that it was difficult to provide support for. We’re keeping our fingers crossed a solution can be found there to bring the Otter Cast Audio to complete feature parity with the original Chromecast Audio.

But this is Hackaday, so just as important as what the Otter Cast Audio does is how it does it. The OtterCast team have skipped right over shoehorning all this magic into a microcontroller and stepped right up to an Allwinner S3 SOC, a capable little Cortex A7 based machine with 128 MB of onboard DDR3 RAM. Pint sized by the bloated standards of a fully interactive desktop, but an absolutely perfect match to juggling WiFi, Bluetooth, Ethernet, and convenient support for all the protocols above. If you’re familiar with these hackers’ other work it won’t surprise you that what they produced here lives up to the typical extremely high quality bar set by such wonders as this USB-C adapter for JBC soldering iron handles and this TS-100 mainboard replacement.

It sounds like a small production run might be on order in the future, but until then production files optimized for a particularly popular Chinese manufacturer are provided, with complete BOM and placement files. It sounds like turnkey production costs from that manufacturer are a shockingly reasonable $10 (total) per unit with most components, and come to a still-reasonable $22 with the remaining self-sourced components manually installed.

For a demo of the finished goods, check out the tweet embedded after the break.

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Better Controls For Your Chromecast Through CEC

Modern home cinema equipment is well-equipped with features for interoperability and convenience, but in practice, competing standards and arcana can make it fall over. Sometimes, you’ve gotta do a little work on your own to glue it all together, and that’s what led [Victor] to develop a little utility of his own.

ChromecastControls is a tool that makes controlling your home cinema easier by improving Chromecast’s integration with the CEC features of HDMI. CEC, or Consumer Electronics Control, is a bidirectional serial bus that is integrated as a part of the HDMI standard. It’s designed to help TVs, audio systems, and other AV hardware to communicate, and allow the user to control an entire home cinema setup with a single remote. Common use cases are TVs that send shutdown commands to attached soundbars when switched off, or Blu-Ray players that switch the TV on to the correct output when the play button is pressed.

[Victor]’s tool allows Chromecast to pass volume commands to surround sound processors, something that normally requires the user to manually adjust their settings with a separate remote. It also sends shutdown commands to the attached TV when Chromecast goes into its idle state, saving energy. It relies on the PyChromecast library to intercept traffic on the network, and thus send the appropriate commands to other hardware. Simply running the code on a Raspberry Pi that’s hooked up to any HDMI port on a relevant device should enable the CEC commands to get through.

It’s a project that you might find handy, particularly if you’re sick of leaving your television on 24 hours a day because Chromecast never bothered to implement a simple CEC command on an idle timeout. CEC hacks have a long history, too – we’ve been covering them as far back as 2010!

Turn Your Old-school CRT Into A YouTube Media Player

Ever wish you could enjoy modern conveniences like YouTube in a retro world of CRTs and late 20th century graphics?

[Johannes Spreitzer] happened to find an old VIENNASTAR CRT (cathode-ray tube television) made by the Austrian brand Kapsh at a flea market. The CRT dates back to 1977 and uses just RF input, making it useless as a modern television set since most TV stations nowadays broadcast primarily in digital.

However, HDMI-to-RF transmitters do exist, making it possible to convert HDMI signals to RF or coaxial cable output to replace an antenna signal. What [Spreitzer] did next was to plug in a Chromcast and essentially convert the CRT into an old-school monitor. You can see some of the trippy graphics in the video below – the video samples shown fit the retro aesthetic, but I’m sure there’s video combinations that would seem pretty out of place.

HDMI-to-RF adapters are pretty easy to pick up at a hardware store, and they allow you to project videos onto specific channels on a CRT. Needless to say, they don’t work the other way around, although since there are still televisions that only pick up RF broadcasts, coaxial to HDMI adapters do exist.

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This Chromecast Volume Knob Has A Certain ’70s Chic

Chromecast devices have become popular in homes around the world in the last few years. They make it easy to cast audio or video from a smartphone or laptop, to a set of speakers or a display connected to the same network. [Akos] wanted to control the volume on these devices with a single, simple piece of equipment, rather than always reaching for a smartphone. Thus was built the CastVolumeKnob.

The project began by using Wireshark to capture data sent by the pychromecast library. Once [Akos] understood the messaging format, this was implemented in MicroPython on an ESP8266. A rotary encoder is used as a volume knob, and a Neopixel ring is used for visual feedback as to the device being controlled and the current volume level.

Further work was done to improve usability, with an ATtiny85 microcontroller being used to monitor the encoder for button presses before waking up the ESP8266, greatly reducing power consumption. The device is also rechargeable, thanks to an 18650 lithium polymer battery, and charger and boost converter boards. It’s all wrapped up in a sleek 3D printed case, with a translucent bezel for the LEDs and a swanky machined aluminium knob as the cherry on top.

It’s a homemade device that nonetheless would be stylish and unobtrusive in the living room environment. We imagine it proves very useful when important phone calls come in and it’s necessary to cut the stereo down to a more appropriate volume.

For another take, check out this USB volume knob with a nice weighty feel, courtesy of lead shot.

UPnP, Vulnerability As A Feature That Just Won’t Die

UPnP — in a perfect world it would have been the answer to many connectivity headaches as we add more devices to our home networks. But in practice it the cause of a lot of headaches when it comes to keeping those networks secure.

It’s likely that many Hackaday readers provide some form of technical support to relatives or friends. We’ll help sort out Mom’s desktop and email gripes, and we’ll set up her new router and lock it down as best we can to minimise the chance of the bad guys causing her problems. Probably one of the first things we’ll have all done is something that’s old news in our community; to ensure that a notorious vulnerability exposed to the outside world is plugged, we disable UPnP on whatever cable modem or ADSL router her provider supplied.

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Fix Your Insecure Amazon Fire TV Stick

I recently spent a largely sleepless night at a hotel, and out of equal parts curiosity and boredom, decided to kill some time scanning the guest network to see what my fellow travelers might be up to. As you’d probably expect, I saw a veritable sea of Samsung and Apple devices. But buried among the seemingly endless number of smartphones charging next to their sleeping owners, I found something rather interesting. I was as picking up a number of Amazon-made devices, all of which had port 5555 open.

As a habitual Android tinkerer, this struck me as very odd. Port 5555 is used for Android Debug Bridge (ADB), a development tool used to control and perform various administrative tasks on an Android device over the network or (more commonly) locally over USB. The number of users who would have legitimately needed to enable network ADB on their devices is surely rather low, so to see a half dozen of them on the network at the same time seemed improbable to say the least.

Why would so many devices manufactured by Amazon all have network ADB enabled? I realized there must be a connection, and it didn’t take long to figure it out.

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