Hackaday Prize 2023: Hearing Sirens When Drivers Can’t

May 25, 2023 by Donald Papp 25 Comments

[Jan Říha]’s PionEar device is a wonderful entry to the Assistive Tech portion of the 2023 Hackaday Prize. It’s a small unit intended to perch within view of the driver in a vehicle, and it has one job: flash a light whenever a siren is detected. It is intended to provide drivers with a better awareness of emergency vehicles, because they are so often heard well before they are seen, and their presence disrupts the usual flow of the road. [Jan] learned that there was a positive response in the Deaf and hard of hearing communities to a device like this; roads get safer when one has early warning.

Deaf and hard of hearing folks are perfectly capable of driving. After all, not being able to hear is not a barrier to obeying the rules of the road. Even so, for some drivers it can improve awareness of their surroundings, which translates to greater safety. For the hearing impaired, higher frequencies tend to experience the most attenuation, and this can include high-pitched sirens.

The PionEar leverages embedded machine learning to identify sirens, which is a fantastic application of the technology. Machine learning, after all, is a way to solve the kinds of problems that humans are not good at figuring out how to write a program to solve. Singling out the presence of a siren in live environmental audio definitely qualifies.

We also like the clever way that [Jan] embedded an LED light guide into the 3D-printed enclosure: by making a channel and pouring in a small amount of white resin intended for 3D printers. Cure the resin with a UV light, and one is left with an awfully good light guide that doubles as a diffuser. You can see it all in action in a short video, just under the page break.

Continue reading “Hackaday Prize 2023: Hearing Sirens When Drivers Can’t” →

Custom Glove Guides Wearers’ Dreams

May 19, 2023 by Bryan Cockfield 6 Comments

For as much advancement as humanity has made in modern medicine even in the last century alone, there’s still plenty we don’t understand about the human body. That’s particularly true of the brain, where something as common as dreams are the subject of active debate about their fundamental nature, if they serve any purpose, and where they originate. One research team is hoping to probe a little further into this mystery, and has designed a special glove to help reach a little deeper into the subconscious brain.

The glove, called Dormio, has a number of sensors and feedback mechanisms which researchers hope will help explore the connection between dreaming and creativity. Volunteers were allowed to take a nap while wearing the glove, which can detect the moment they began entering a specific stage of sleep. At that point, the device would provide an audio cue to seed an idea into the dreams, in this case specifically prompting the sleeper to think about trees. Upon awakening, all reported dreaming about trees specifically, and also demonstrated increased creativity in tests compared to control groups.

While this might not have the most obvious of implications, opening the brain up to being receptive of more creative ideas can have practical effects beyond the production of art or music. For example, the researchers are also investigating whether the glove can help individuals with post-traumatic stress disorder manage nightmares. From a technical perspective this glove isn’t much different from some other devices we’ve seen before, and replicating one to perform similar functions might be possible for most of us willing to experiment on ourselves.

Op-Amp Challenge: Compare Op-Amps, By Listening To Them

May 7, 2023 by Jenny List 31 Comments

In the world of audiophilia there are arguments that rage over the relative merits of particular components. Sometimes this can reach silly levels as in the high-end ALPS pot we once saw chosen as a volume control whose only task was to be a DC voltage divider feeding a pin on a DSP, but there are moments where such comparisons might have a bit of merit. To allow the comparison of different op-amps in a headphone amplifier, [Stephan Martin] has created a stereo amplifier board complete with sockets to take single or dual op-amp chips.

The circuit is based upon a design from the 1990s which as far as we can see is a pretty conventional non-inverting amplifier. It has an on-board op-amp to create a virtual ground, and three sockets for either two single or one dual op-amp to create a stereo headphone amplifier.

So the burning question is this: will you notice a difference? We’re guessing that assuming the op-amps under test are to a sufficient specification with a high enough impedance input and enough output current capability, the differences might be somewhat imperceptible without an audio analyser or the hearing of a ten-year-old child.

Need more of an audio fix? Try our Know Audio series.

This One Simple Trick Rehabilitates Scratchy Sounding Speakers

April 20, 2023 by Lewin Day 13 Comments

We’ve all picked up a radio and switched it on, only to hear an awful scratchy noise emitting from the speaker. [Richard Langer] is no stranger to this problem, and has identified a cheap and unusual solution—using toilet paper!

The cause of the scratchy sound is that when the speaker’s paper cone warps, it can cause the voice coil to rub up against the magnet assembly. In time, this wears out insulation on the coil’s turns, damaging the speaker. [Richard] found that realigning the coil to its proper place would rectify the issue. This can be achieved by stuffing a small amount of toilet paper in the back of the speaker, between the cone and the metal housing.

To identify the right spot to put the paper, one simply presses on the back of the speaker with a pen while listening out for the scratchy sound to stop. The paper can then be stuffed into this area to complete the fix. This can realign the cone and voice coil and stop the scratchy sound for good.

[Richard] notes that this method can be quite long-lasting in some cases. Failing that, it should serve long enough for you to order a replacement speaker. Video after the break.

Continue reading “This One Simple Trick Rehabilitates Scratchy Sounding Speakers” →

It’s Difficult To Read An Audiophile Guide As An Analogue Engineer

March 28, 2023 by Jenny List 138 Comments

Sitting on a train leaving the Hackaday Berlin conference, and Hacker News pops up Julian Shapiro with a guide to HiFi. What Hackaday scribe wouldn’t give it a click, to while away the endless kilometres of North European Plain!

It’s very easy as an analogue electronic engineer, to become frustrated while reading audiophile tracts, after all they have a tendency to blur superficial engineering talk with pseudoscience. There’s a rich vein of parody to be found in them, but nevertheless it’s interesting to read them because just sometimes the writer gets it and doesn’t descend into the world of make-believe. Continue reading “It’s Difficult To Read An Audiophile Guide As An Analogue Engineer” →

A Feature-Rich Amplifier Module For 3-Way Speaker Builds

March 20, 2023 by Lewin Day 22 Comments

There’s something rewarding about building your own DIY audio hardware. Knowing you put it together yourself gives you faith in the construction, and psychosomatically makes the music sound all that much sweeter. If you’re into that kind of thing, you might like to give [Eric Sorensen’s] Denmark amplifier module a look.

The amplifier is intended to be used in a 3-way system, running a subwoofer, woofer, and tweeter. It uses a 1000 W ICEpower module to run the subwoofer, with a pair of 500W ICEpower modules to run the woofer and tweeter respectively. Meanwhile, a MiniDSP 2x4HD is used to accept optical audio input. It also offers digital signal processing and serves as a crossover to split the signal across the three speakers. An STM32F401 is used to run the show, controlling all the various modules and the necessary status LEDs. It’s a feature-rich build, too, with overtemperature monitoring, fan control, and clipping warnings built in.

The whole setup is built on to a sturdy aluminium backplate. The CNC-machined panel has simple tactile buttons for control. There’s also a nifty use of clear PETG 3D printer filament as a light pipe for LEDs. It’s effective, and it looks great. The whole module is designed to slide into the bottom of a 3-way speaker housing like a drawer.

Overall, if you’re building a big set of 3-way speakers, you might find the Denmark amplifier module is perfect for your needs. Alternatively, you could experiment with a different kind of speaker entirely. Video after the break.

Continue reading “A Feature-Rich Amplifier Module For 3-Way Speaker Builds” →

A Tape Loop Echo You Can Build

March 10, 2023 by Jenny List 18 Comments

Echo and reverb are now electronic audio effects done in a computer or an integrated circuit, but originally they were achieved through mechanical means. Reverb units used springs, and echo units used loops of magnetic tape. As a musician hankering after a mechanical tape echo unit, [Adam Paul] was left with no choice but to build his own. We featured an early prototype, but now he’s back with a finished version that’s intended to be replicated by other musicians.

The unit takes a cassette mechanism from one of the last still-manufactured players available through the usual sources. It splits record and play heads, with the normal cassette replaced with a tape loop made from extra-thick computer tape. A custom PCB replaces most of the electronics, and the auto-reverse system is disabled.

The result is a functional tape echo system, as can be seen in the video below the break. This is ready to build yourself, with everything on a GitHub repository and an extremely comprehensive build guide, so do any of you fancy a go?

Read about the device’s earlier incarnation here.

Continue reading “A Tape Loop Echo You Can Build” →