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.

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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.

Vintage Philco Radio Looks Stock, Contains Modern Secret: A Raspberry Pi

July 7, 2019 by Jenny List 69 Comments

Antique radio receivers retain a significant charm, and though they do not carry huge value today they were often extremely high quality items that would have represented a significant investment for their original owners. [CodeMakesItGo] acquired just such a radio, a Philco 37-11 made in 1937, and since it was it a bit of a state he set about giving it some updated electronics. Vintage radio purists, look away from the video below the break.

Stripping away the original electronics, he gave it a modern amplifier with Bluetooth capabilities, and a Raspberry Pi. Vintage radio enthusiasts will wince at his treatment of those classic parts, but what else he’s put into it makes up for the laying waste to a bit of ’30s high-tech.The original tuning dial was degraded so he’s given it a reproduction version, and behind that is an optical encoder and two optical sensors. This is used to simulate “tuning” the radio between different period music “stations” being played by the PI, and for an authentic feel he’s filled the gaps with static. The result is a functional and unusual device, which is probably better suited than the original to a 2019 in which AM radio is in decline.

If you think of a high-end set like this Philco as being the ’30s equivalent of perhaps an 8K TV set, you can imagine the impact of AM radio in those early days of broadcasting. We recently took a look at some of the directional antenna tricks that made so many AM stations sharing the band a possibility.

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