[Ronald] has been improving his audio set-up for a while now, his latest revision culminating in this WiFi enabled center channel speaker. It all started with feature creep as you can see in this direct quote, “Being an engineer, I couldn’t stop here, not now that I had a way of adding more features…”
He had purchased a new amplifier for his system, but was irritated that the loudness setting would re-enable itself every time he switched inputs. First he thought he might just have a little board that intercepted the signals from his remote and tacked on the loudness off signal. It occurred to him that it would be even cooler if he could control it from his computer or phone. So he opened the case on his new amp and discovered an i2c break-out. We can guess how it went after that.
In version 2.0 he kept most of his work from 1.0, but wanted to simplify the set-up and build it all into a center speaker unit since an amplifier and two speaker cabinets takes up too much room. He fit a similar set-up as before in the center speaker casing, but added a touch screen and a few other improvements. Though, strangely, he ran into some problems upgrading to the Raspberry Pi 2.0 and had to revert.
The final result is very nice, though obviously not done. As the engineer’s mantra goes, “If it ain’t broke, it doesn’t have enough features yet.”
[Henrik Langer] put his powerful audio acquisition and output board up on Hackaday.io, and we thought we’d point it out to you. It’s one of those projects that used to be pro audio just a few years back, but is doable (and affordable) DIY today: dual stereo inputs and four(!) stereo outputs, all sampled at 24 bits and up to 192 kHz. It’s configured as a BeagleBone cape, and comes with a customized Linux distribution for the ‘Bone.
What would you do with such a thing? It’s essentially a recording studio in your pocket, with a computer attached. The video (linked below the break) demonstrates using the device as a real-time stereo delay effect unit, but that’s only making use of one channel. Between effects, recording, and then all sorts of much-better-than-CD quality sound synthesis and playback possibilities, it’s an open-ended audio playground.
And all that from what is essentially a (very well-done) breakout board for a fancy DAC/ADC chip from Analog Devices: the AD1938. We’d love to have one of these on our desktop. Check out [Henrik]’s GitHub for the PCB and build instructions and BOM and everything else you’d need to get started. Very nice job!
Continue reading “Aquire Awesome Audio for BeagleBone”
The minuscule size of the Raspberry Pi Zero makes it perfect for hacks where size is a factor. For example, a small, standalone device for getting streaming audio into your speakers. The RPi Zero doesn’t have an audio output on board, so PolyVection paired it up with their PlainDAC to build a minimal audio streaming device.
Their build uses a few lines from the GPIO header to drive an I2S digital to analog converter. The DAC is a PCM5142 from Texas Instruments that provides high quality sound output, and contains a built in programmable DSP.
The hardware fits into a 3D printed case, coming in at 68 mm by 48 mm. There’s no WiFi inside, but this can be added with an external USB device for wireless streaming. The DAC used is supported by the Linux kernel, so a simple configuration is all that’s needed to pipe audio out.
Once you have a device like this assembled, you can install a server like Music Player Daemon to remotely control the device and cue up internet radio channels.
The new Raspberry Pi Zero is generating a lot of discussion, especially along the lines of “why didn’t they include…?” One specific complaint has been that audio is only available through the HDMI port. That’s not entirely true as pointed out by Lady Ada over at Adafruit.
Something to remember about the entire Pi family is the pins on the Broadcom processors are multipurpose. Does it increase the confusion or the capabilities? Take your pick. But the key benefit is that different pins can handle the same purpose. For audio the Greater Than Zero Pis (GTZPi) use PWM0_OUT and PWM1_OUT on the processor’s GPIO pins 40 and 45. On the GRZPis these feed a diode, resistor and capacitor network that ends at the audio output jack. They don’t appear on the GPIO connector so cannot be used on the Zero.
The multi-pin, multi-purpose capability of the Broadcom processor allows you to switch PWM0_OUT to GPIO 18 and PWM1_OUT to GPIO 13 or 19. Add the network from the Adafruit note, or check this schematic from the Raspberry Pi site – look at the lower right on the second page.
While you’re checking out the audio hack at Adafruit, read through the entirety of Introducing the Raspberry Pi Zero. Lady Ada provides a great description of the Zero and what is needed to start using it.
If you’re looking for Zero hacking ideas you might check the comments in our announcement about the Zero or article on the first hack we received. There is a lot of grist for the hacking mill in them.
With the ability to run a full Linux operating system, the Intel Edison board has more than enough computing power for real-time digital audio processing. [Navin] used the Atom based module to build Effecter: a digital effects processor.
Effecter is written in C, and makes use of two libraries. The MRAA library from Intel provides an API for accessing the I/O ports on the Edison module. PortAudio is the library used for capturing and playing back audio samples.
To allow for audio input and output, a sound card is needed. A cheap USB sound card takes care of this, since the Edison does not have built-in hardware for audio. The Edison itself is mounted on the Edison Arduino Breakout Board, and combined with a Grove shield from Seeed. Using the Grove system, a button, potentiometer, and LCD were added for control.
The code is available on Github, and is pretty easy to follow. PortAudio calls the
audioCallback function in effecter.cc when it needs samples to play. This function takes samples from the input buffer, runs them through an effect’s function, and spits the resulting samples into the output buffer. All of the effect code can be found in the ‘effects’ folder.
You can check out a demo Effecter applying effects to a keyboard after the break. If you want to build your own, an Instructable gives all the steps.
Continue reading “Audio Effects on the Intel Edison”
Although graphical programming languages have been around for ages, they haven’t really seen much use outside of an educational setting. One of the few counterexamples of this is Pure Data, and Max MSP, visual programming languages that make music and video development as easy as dropping a few boxes down and drawing lines between them.
A few years ago, [Thomas] and [Danny] developed a very cool Pure Data audio-visual presentation. The program they developed only generated graphics, but though clever coding they were able to generate a few audio signals from whatever video was coming out of their computer. The project is called TVestroy, and it’s one of the coolest audio-visual presentations you’ll ever see.
The entire program is presented on three large screens and nine CRT televisions. With some extremely clever code and a black box of electronics, the video becomes the audio. Check it out below.
Although this is a relatively old build, [Thomas] thought it would be a good idea to revisit the project now. He’s open sourced most of the Pure Data files, and everything can be downloaded on the project page.
Continue reading “Video from Audio and Pure Data”
A lot of digital processes are named after an old analog device that they’ve since replaced. It’s not uncommon to “tape” a show nowadays, for example, even though the recording work is actually done by a digital video recorder. Sometimes, though, the old analog devices have a certain je ne sais quoi that is desirable even in today’s digital world. This is certainly the case with [Dima]’s tape loop echo which is actually made with a physical tape loop.
The process of building the tape loop hardware is surprisingly non-technical. By positioning a recording head and a playback head right next to one another, a delay is introduced. An echo is created by mixing the original live sound signal with this delayed signal coming from the tape By varying the speed of the tape or altering several other variables, many different-sounding effects can be achieved.
Although in practice it’s not as simple as it sounds (the device required a lot of trial-and-error), the resulting effect is one that Pink Floyd or Beck would surely be proud of. Analog isn’t the only way to go though, there are plenty of digital effects that are easily created, and some with interesting mounting options as well.
Continue reading “Tape Loop Echo Made With an Actual Tape Loop”