Sniffing Signals To Teach Old Speakers New Tricks

February 12, 2020 by Tom Nardi 24 Comments

Like many of the stories you’ll find on these pages, this one starts with a user being annoyed about their device’s inability to perform a simple task. All [Jay Tavares] wanted was for his Bose Cinemate speakers to turn themselves on and off as needed. It seems like a reasonable enough request, and indeed, is exactly the point of HDMI’s Consumer Electronic Control (CEC) feature. But in this case, it would take a bit of custom hardware to get similar functionality.

Unfortunately, the speakers [Jay] has only support optical audio; so any interoperability with HDMI-CEC (hacked or otherwise) was immediately out the window. Still, he reasoned that he should be able to detect when the TOSLINK audio source is actually active or not, and give the speaker system the appropriate signal to either power on or shut down. You might think this would require some kind of separate stand-alone device, but as it turns out, all the necessary information was available by reverse engineering the connection between the receiver and the subwoofer.

After some investigation, [Jay] found that not only was the content of the TOSLINK audio source being sent over this DB9 cable, but so were the control signals required to turn the system on and off. So he designed a simple pass-through device with an ATtiny85 and a couple passives that latches onto the relevant lines in the cable.

When audio is detected over the optical connection, the MCU will inject the appropriate signals on the control line to simulate the user pressing the “Power” button the remote. When the chip hasn’t detected audio after 10 seconds, it sends the signal to shut the speakers off.

While [Jay] notes he can’t guarantee this works on anything other than the particular Bose Cinemate GS Series II system he has, we’d be willing to bet the concept could be adapted to other models or even brands that use a similar cable to link their principle components. If all else fails, you could always add an ESP8266 to your sound system and control it over WiFi.

THAT Preamp

January 25, 2020 by Al Williams 2 Comments

It is easy to cobble together projects these days. ICs make it simple and microcontrollers even easier. However, we always respect a project that really goes from concept to finished product and that’s what we liked about [Curt Yengst’s] “THAT” Thing microphone preamp.

In part 1 of his post about it, he talks about the basic ideas including the chips from THAT — a small but high-end audio chipmaker — he uses. The first chip is a low-noise audio preamp and the other is a balanced line driver.

In part 2, we get to see [Curt] go from breadboard testing to PCB fabrication all the way to the finished rack-mounted device with a good looking front panel. It worked, but like all designers, [Curt] was already thinking about the next version.

Continue reading “THAT Preamp” →

Better Controls For Your Chromecast Through CEC

January 14, 2020 by Lewin Day 34 Comments

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!

ESP8266 Unlocks Hidden Features In Sound Bar

October 24, 2019 by Tom Nardi 22 Comments

It’s no secret that the hardware devices we buy are often more capable than their manufacturer leads on. Features hidden behind firmware locks are a common trick, as it allows companies to sell the same piece of gear as a different model by turning off certain capabilities. Luckily for us, these types of arbitrary limitations are often easy to circumvent.

As a perfect example, [Acuario] recently discovered that the LG SJ2 sound bar has quite a few features that aren’t advertised on the box. Whether it’s due to greed or just laziness, it turns out LG isn’t using many of the capabilities offered by the ESMT AD83586B IC inside the amplifier. The chip gets its configuration via I2C, so thanks to the addition of an ESP8266, the expanded capabilities can now be easily enabled through a web interface.

[Acuario] has already found out how to turn on things like simulated surround sound, or per-channel volume controls; all functions which aren’t even exposed through the normal controls on the sound bar. But it goes deeper than that. The LG SJ2 is a 2.1 channel system, with a wireless speaker providing the right and left channels. But the AD83586B inside the subwoofer is actually capable of driving two locally connected speakers, though you obviously need to do a little rewiring.

There are still even more capabilities to unlock, though [Acuario] is currently struggling with some incomplete documentation. The datasheet says there’s support for user-defined equalizer settings, but no examples are given for how to actually do it. If anyone’s got a particular affinity for these sort of amplifier chips, now could be your time to shine.

For hackers, there’s perhaps no better example of feature-locked products than Rigol’s line of oscilloscopes. From the 2000 series of scopes in 2013 up to their higher-end MSO5000 just last year, there’s a long history of unlocking hidden features on these popular tools.

Quality Sound-Proof Cans From Personal Protective Equipment

October 12, 2019 by Jenny List 13 Comments

Working in a noisy office can be distracting. To combat the problem in his workplace [Rikard Anglerud] bought himself a pair of 3M ear defenders. They were good, but not quite good enough to completely extinguish the noise, so he inserted the drivers from a pair of cheap headphones and played a low-level white noise. This prototype proved effective, so he returned to the project and produced a much nicer pair that approach much more costly cans in their execution.

[Rikard’s] first set of headphones left something to be desired in the quality department. The second set followed with a pair of better-quality drivers sourced online, and more care was taken with cable routing and in their fitting. Finally some filler was used to remove the moulded 3M branding, and make them look more hi-fi than workwear.

From an audiophile perspective these cans might not approach a very high quality pair because their drivers are unlikely to be matched to the acoustic properties of their enclosures. But it sounds as though he’s achieved an adequate result despite that, and completely satisfied his need to exclude office noise.

ESP8266 Controls TiVo Over The Network

August 11, 2019 by Tom Nardi 13 Comments

Remember the TiVo? The set-top DVR that was once so popular of a hacking target that Hackaday had a dedicated subdomain for it has today largely faded into obscurity as time-shifted viewing has given way to Internet streaming services like Netflix and Hulu. But make no mistake, while the TiVo may no longer be the centerpiece of the average home entertainment center, there’s a diehard group of antennaed aficionados that are still rocking (and hacking) them.

One such TiVotee is [Thomas McQueen], who recently discovered his TiVo-powered Virgin Media V6 DVR was listening for commands on the network. After finding some official documentation for the protocol and firing off a couple of test commands from his computer’s telnet client, he realized he had an opportunity to flex his microcontroller muscle and create a library that would allow controlling the set-top box with the ESP8266 or other network-capable MCU.

[Thomas] built his project on-top of the basic Arduino WiFi library, making every effort to make it as generalized as possible so it could work on a multitude of platforms and with various targets. He even made sure to give all his functions friendly names that won’t leave users scratching their head when they read through example code down the road. We’ve seen far too many software projects that were poorly documented or obtusely programmed, so it’s always good to see somebody putting some forethought into their code.

The library makes it easy to add TiVo control to your project, but [Thomas] went one step further and came up with an example application that provides a web interface on the ESP8266 or ESP32. Any device with a web browser, such as a smartphone, can connect to the UI and fire off commands to the TiVo. His next step is to combine his library with some code to talk to Amazon’s Alexa so he’ll be able to control playback with his voice.

We’ll hand it to these TiVo users, they’re a tenacious lot. Earlier in the year, we covered how one dedicated TiVo fan managed to brute-force the child lock on his DVR using the Arduino and an IR LED.

Does This Timber Have The Right Timbre?

July 27, 2019 by Jenny List 20 Comments

A hi-fi amplifier used to be a rite of passage for the home electronic constructor, back in the days when consumer electronics was still dominated by analogue entertainment. It’s unusual then to see [carbono.silício]’s stereo amplifier project, constructed in an open-wire circuit sculpture form on a log. You didn’t read that incorrectly, it’s built not on a breadboard but on a piece of Olea Maderensis, or Madiera Olive wood, complete with bark. This endangered tree was not felled, instead it was a piece blown down after a storm.

The circuit is slightly unusual for a project such as this, in that it uses a pair of LM386 audio amplifier chips. This isn’t an unusual component, but it’s one more commonly seen providing the amplification for a small speaker project than in a stereo hi-fi amplifier. But the construction is beautifully done, with very neatly routed wires, a single central volume knob, and a blue LED power light. A particularly nice touch are the aluminium electrolytic capacitors, we suspect having had their plastic sleeving removed.

We’ve had our share of stereo amp projects here, and some of them are surprisingly simple. We have even been known to partake of them ourselves.