Pocket Radio Powered By Tiny Microcontroller

July 6, 2022 by Bryan Cockfield 33 Comments

Before the days of MP3 players and smartphones, and even before portable CD players, those of us of a certain age remember that our cassette players were about the only way to take music on-the-go. If we were lucky, they also had a built-in radio for when the single tape exhausted both of its sides. Compared to then, it’s much easier to build a portable radio even though cassettes are largely forgotten, as [wagiminator] shows us with this radio design based on an ATtiny.

The build is about as compact as possible, with the aforementioned ATtiny 402/412 as its core, it also makes use of an integrated circuit FM tuner, an integrated audio amplifier with its own single speaker, and a small OLED display. The unit also boasts its own lithium-polymer battery charger and its user interface consists of only three buttons, plenty for browsing radio stations and controlling volume.

The entire build fits easily in the palm of a hand and is quite capable for a mobile radio, plus all of the schematics and code is available on the project page. While it doesn’t include AM capability, just the fact that FM is this accessible nowadays when a few decades ago it was cutting-edge technology is quite remarkable. If you’re looking for an even smaller FM receiver without some of the bells and whistles of this one, take a look at this project too.

Generate Fully Parametric, 3D-Printable Speaker Enclosures

November 28, 2021 by Donald Papp 9 Comments

Having the right speaker enclosure can make a big difference to sound quality, so it’s no surprise that customizable ones are a common project for those who treat sound seriously. In that vein, [zx82net]’s Universal Speaker Box aims to give one everything they need to craft the perfect enclosure.

The parts can be 3D-printed, but the design ensures that the front and back panels are flat, so one can use wood or some other material for those depending on preference and appearance. The assembly is screwed together using six M3 bolts per side with optional heat-set inserts, but it’s entirely possible to simply glue the unit together if preferred.

One thing that makes this design a bit more broadly useful is that [zx82net] not only provides the parametric design file for Fusion360, but also includes STEP format CAD files, and a small number of pre-configured assemblies for a few commonly available speaker drivers: the Dayton Audio DMA70-4, ND91-4, and the TCP115-4. Not enough for you? Check out [zx82net]’s collection of ready-to-rock enclosures in a variety of designs and configurations; there’s bound to be something to appeal to just about anyone.

[via Reddit]

Arduino Orchestra Plays The Planets Suite

September 26, 2021 by Lewin Day 13 Comments

We’ve seen a great many Arduino synthesizer projects over the years. We love to see a single Arduino bleeping out some monophonic notes. From there, many hackers catch the bug and the sky is truly the limit. [Kevin] is one such hacker who now has an Arduino orchestra capable of playing all seven movements of Gustav Holst’s Planets Suite.

The performers are not human beings with expensive instruments, but simple microcontrollers running code hewn by [Kevin’s] own fingertips. The full orchestra consists of 11 Arduino Nanos, 6 Arduino Unos, 1 Arduino Pro Mini, 1 Adafruit Feather 32u4, and finally, a Raspberry Pi.

Different synths handle different parts of the performance. There are General MIDI synths on harp and bass, an FM synth handling wind and horn sections, and a bunch of relays and servos serving as the percussive section. The whole orchestra comes together to do a remarkable, yet lo-fi, rendition of the whole orchestral work.

While it’s unlikely to win any classical music awards, it’s a charming recreation of a classical piece and it’s all the more interesting coming from so many disparate parts working together. It’s an entirely different experience than simply listening to a MIDI track playing on a set of headphones.

We’d love to see some kind of hacker convention run a contest for the best hardware orchestra. It could become a kind of demoscene contest all its own. In the meantime, scope one of [Kevin’s] earlier projects on the way to this one – 12 Arduinos singing Star Wars tracks all together. Video after the break.

Continue reading “Arduino Orchestra Plays The Planets Suite” →

Meet The Marvelous Macro Music Maker

September 23, 2021 by Kristina Panos 1 Comment

Do you kind of want a macropad, but aren’t sure that you would use it? Hackaday alum [Jeremy Cook] is now making and selling the JC Pro Macro on Tindie, which is exactly what it sounds like — a Pro Micro-based macro keypad with an OLED screen and a rotary encoder. In the video below, [Jeremy] shows how he made it into a music maker by adding a speaker and a small solenoid that does percussion, all while retaining the original macro pad functionality.

[Jeremy]’s original idea for a drum was to have a servo seesawing a chopstick back and forth on the table as one might nervously twiddle a pencil. That didn’t work out so well, so he switched to the solenoid and printed a thing to hold it upright, and we absolutely love it. The drum is controlled with the rotary encoder: push to turn the beat on or off and crank it to change the BPM.

To make it easier to connect up the solenoid and speaker, [Jeremy] had a little I²C helper board fabricated. There’s one SVG connection and another with power and ground swapped in the event it is needed. If you’re interested in the JC Pro Macro, you can pick it up in various forms over on Tindie. Of course, you might want to wait for version 2, which is coming to Kickstarter in October.

There are many ways to make a macro keyboard. Here’s one that also takes gesture input.

Continue reading “Meet The Marvelous Macro Music Maker” →

Know Audio: A Loudspeaker Primer

June 25, 2021 by Jenny List 27 Comments

As we’ve started out on our journey through the world of Hi-Fi audio from a strictly practical and engineering viewpoint without being misled by any audiophile woo, we’ve already taken a look at the most important component in any audio system: the listener’s ear. It’s time to move down the chain to the next link; the loudspeaker.

Sound is pressure waves in the air, and the purpose of a loudspeaker is to move the air to create those waves. There are a variety of “exotic” loudspeaker technologies including piezoelectric and electrostatic designs, here we’ll be considering the garden variety moving-coil speaker. It’s most usually used for the large bass or smaller mid-range drivers in a typical speaker system. Continue reading “Know Audio: A Loudspeaker Primer” →

IPod HiFi Gains New High Notes

June 19, 2021 by Jenny List 1 Comment

The iPod HiFi was a stereo speaker add-on produced by Apple in the mid-2000s for their iPod range, a $300-plus speaker cabinet with twin drivers per channel, an iPod dock, aux, and TOSLINK interfaces. It’s caught the eye of [Jake], in particular one posted on Reddit that had an extra set of tweeters to improve the HiFi’s lackluster treble. The question was that it might have been an Apple prototype, but lacking his own [Jake] set out to replicate it.

The job he’s done is to a high quality. The baffle has first 3D scanned, and then recesses were milled out of it so the tweeters could be press-fit in. He’s driving them through a simple LC crossover circuit taken from the speaker drive, and reports himself happy with the result.

Unfortunately, we still don’t know whether or not the Reddit original was an Apple prototype or not. We’d be inclined to say it isn’t and praise the skills of the modder who put the tweeters in, but in case it might be we’d point to something that could deliver some clues. The iPod HiFi didn’t use a passive crossover, instead it had a DSP and active crossover, driving four class D amplifiers. If you find one with tweeters and they’re driven from the DSP through an extra pair of amplifiers then put it on eBay as a “RARE BARN FIND APPLE PROTOTYPE!” and make a fortune, otherwise simply sit back and enjoy the extra treble a previous owner gave it.

Of course, some people baulked at the price tag of the Apple speaker, and made their own.

Using Ikea Guts To Add Sonos Compatibility To A Vintage Speaker

May 15, 2021 by Jenny List 8 Comments

We’re in a fortunate position when it comes to audio gear, because advances in amplifier and signal processing technology have delivered us budget devices that produce a sound that’s excellent in comparison to those of a few years ago. That said, a decent quality device is good whichever decade it was manufactured in, and a speaker from the 1960s can be coaxed into life and sound excellent with a modern amplifier. It’s something [Sebastius] has explored, as he picked up an attractive-looking set of Swedish speakers from the 1960s. Wanting to bring them into the 21st century, he’s upgraded them for Sonos compatibility by hacking in the guts of an IKEA Symfonisk bookshelf speaker.

The speakers themselves looked good enough, but on closer examination they proved to bear the scars of many decades. After testing new wiring and drivers they still had a good sound to them. Their passive crossover meant that hooking them up to a single amplifier is as straightforward as it was decades ago, but a Symfonisk has an active crossover and two amplifiers. Fortunately there’s a neat hack by which those two amplifiers can be combined as one, and this is what he’s done with the resulting Symfonisk electronic package mounted on the reverse of the speaker.

The fate of the original speaker’s broken mid-range and tweeter drivers was a common enough one back in the day as speakers were ill-matched to amplifiers. Too small an amp would need turning up in volume to get a good sound resulting in distortion that would burn out the top end drivers, while too much power would result in the bass drivers being overloaded and failing. It’s unclear whether the drivers in a vintage speaker would be well-matched to an amplifier such as the Symfonisk, but we’re guessing they are safe while run at sensible volumes. Perhaps of more interest is whatever on-board DSP a Symfonisk contains, because while vintage speakers were designed for as flat a response as possible, modern compact speakers use DSP to equalise the frequency and phase responses of otherwise not-very-good-sounding enclosures. If the Symfonisk does this then those adjustments will appear as distortion in the sound of a different cabinet, but the question remains whether that distortion will be significant enough to be detectable by ear.

If the Symfonisk catches your attention, we’ve covered a teardown of it in the past.