ARM Board Transmits FM

There is more than a casual link between computer people and musicians. Computers have created music since 1961 when an IBM7094 sang the song Daisy Bell (later inspiring another computer, the HAL 9000, to do the same).

[Vinod.S] wanted to create music on an STM32F407 Discovery board, but he also wanted it to play on his FM radio. He did it, and his technique was surprising and straightforward. The key is that the ARM processor on the Discovery board uses an 8MHz crystal, but internally (using a phase-locked loop, or PLL) it produces a 100MHz system clock. This happens to be right in the middle of the FM radio band. Bringing that signal back out of the chip on a spare output pin gives you the FM carrier.

That’s simple, but a carrier all by itself isn’t sufficient. You need to FM modulate the carrier. [Vinod.S] did the music playback in the usual way and fed the analog signal via a resistor to the crystal. With some experimentation, he found a value that would pull the crystal frequency enough that when multiplied up to 100MHz, it would produce the desired amount of FM deviation. You can see a video of the whole thing in action, below.

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Upcycle Old Speakers With C.H.I.P.

Sometimes you get a piece of hardware that’s so cool you can’t help but fix it back up. There are a lot of companies after that sweet, sweet Raspberry Pi money, and the $9 US Dollar C.H.I.P. is a very interesting contender for the space. We have been especially enjoying the stream of neat hacks and example projects they’ve been putting out.

In this case, [Peter] wanted to get a pair of walnut speakers up to modern standards. Already suffering from a glut of audio equipment in his personal space, he decided to sweeten the deal by adding support for his library of music.

The first step was ordering a new set of drivers to replace the aged 40-year-old ones occupying the set. After he got them installed, he added C.H.I.P., a power supply, an amplifier, and a 500GB hard-drive. The controlling software behind the installation is the venerable mpd. This way he can control the speakers from any device in his house as long as he had an interface installed for the daemon.

We’re glad these speakers didn’t end up in the garbage behind a goodwill somewhere, and they do look good.

Wifi Enabled Center Speaker

[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.”

Incredible Marble Music Machine

We tried to figure out how to describe the band [Wintergatan]. It took a lot of googling, and we decided to let their really incredible music machine do it for them. The best part? Unlike some projects like this that come our way, [Wintergatan] documented the whole build process in an eight part video series.

The core of the machine is a large drum with two tracks of alternating grey and black Lego Technic beams and pins. The musician sequences out the music using these. The pins activate levers which in turn drop ball bearings on the various sound producing devices in the machine. The melody is produced by a vibraphone. At first we thought the drum kit was electronic, but it turns out the wires going to it were to amplify the sound they made when hit. At the end of their travel the bearings are brought up to the hopper again by a bucket conveyor.

The final part count for the machine sits at 3,000 not including the 2,000 ball bearings rolling around inside of it. If you’ve ever tried to make a marble machine, then you’ll be just as impressed as we were that the machine only appeared to lose a few marbles in the course of a three minute song. Aside from the smoothness of the machine, which is impressive, we also enjoyed the pure, well, hackiness of it. We can spy regular wood screws, rubber bands, plywood, bits of wire, and all sorts of on-the-spot solutions. Just to add bonus cool, the whole project appears to have been built with  just a bandsaw, a drill press, and a few hand power tools.

The machine is great, but we also really appreciate the hacker spirit behind it. When a commenter on a YouTube video told him he was a genius, he replied, “Thank you for that! But I do think, though, that it is mostly about being able to put in the time! I mean the talent of being stubborn and able to see things through are more important than the abilities you have to start with. If you work hard on anything, you will learn what you need and success! Its my idea anyway! So happy people like the machine!”. Which we think is just as cool as the machine itself. Video of the machine in action and part one of the build series after the break!

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A Wooden Performance Is Fine WIth This Sequencer

You could sometimes be forgiven for thinking that making popular music has become too easy. With a laptop and suitable software almost anybody can now assemble something that had they secured the services of a canny promoter would be in with a shot at stardom. So many performances have been reduced to tightly choreographed dance acts to mask the absence of musicians or indeed musical talent, and our culture is poorer for it. It’s not that music made with modern technology or outside the performance is an indicator of lack of talent, indeed when a truly talented musician makes something with the resources of a modern technology the results are astounding. Instead it perhaps seems as though the technology is cheapened by an association with mediocrity when it should be a tool of greatness.

So it was with pleasure that we noticed a fresh project on Hackaday.io this morning which provides a marriage of accessible music technology and a requirement for performance. [Ernest Warzocha] has made a wooden sequencer.

It’s true, audio sequencers are old hat, so a new one will have to work hard to enthuse a seasoned Hackaday reader who’s seen it all. What makes [Ernest’s] sequencer different is that he’s made one with a very physical interface of wooden pucks placed in circular recesses on a wooden surface. Each recess has an infra-red reflective sensor that detects the surface texture of the puck placed in it and varies the sample it plays accordingly. It’s all held together underneath by an Arduino, and MP3 samples are played by a Sparkfun MP3 shield. At a stroke, he has turned the humble sequencer from a workaday studio tool into a performance art form that you can see in the video below, and we like that.

Home made sequencers have a special place in maker culture, and as you might expect over the years we’ve featured quite a few of them. Shift registers, CMOS analogue switches or even turntables as the sequencer elements, Lego as a human interface, a sequencer made from a cash register, and a rather lovely steampunk sequencer, to name but a few. So this one joins a rich tradition, and we look forward to more in the future.

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A Slew of Open-Source Synthesizers

Hackaday reader [Jan Ostman] has been making microcontroller-based DIY synthesizers for quite a while now. Recently, he’s opened up the source for a lot of them so that you can play along at home. All of these virtual-analog synths and soundmakers can be realized on an Arduino or AVR ATmega328 if you happen to have one lying around.

Extra parts like a keyboard, some pushbuttons, or some potentiometer knobs to twiddle won’t hurt if you’d like to make something more permanent or more obviously playable, like [Jan] does. On the other hand, if you’d just like to get your feet wet, I’ve tweaked his code to be more immediately plug-and-play. The code is straightforward enough that it’s a good learning platform. So let’s take a quick tour through three drum machines and a string synth, each of which you can build on a breadboard in just a few minutes.

To install on an Arduino UNO, fetch the zip file from this GitHub repository, and move each subfolder to your Arduino sketch directory. You’re ready to play along.

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Mid Century Modern Speaker from 90s Road Trash

[BarryAbrams] found some 90s speakers on the side of the road.  At first he thought he might have made a real score, but his coworker who knows about this sort of thing (we all have one) let him know they were merely average. Undaunted, he removed the speakers from their MDF housing, fixed a small dent in one of the tweeters, and got to work.

He cut a new frame for the speakers out of plywood. He adorned the plywood box with maple and walnut from a local supplier. The box then got a coat of urethane. His skill at sign making showed in the final finish, and the wood looks very good. Our only complaint is the straight legs instead of the slightly angled and tapered ones common to mid-century modern furniture style.

The electronics are a Chinese amp and a Sonos knock-off. [Barry] only needed to control the volume and power for the speaker set. He came up with a clever 3D-printed knob and switch configuration. When the volume is turned all the way down the speaker set turns off.

The end result sounds and looks better than anything he could get for the $125 US Dollars he spent on the project. We certainly wouldn’t complain if this were a fixture in our living space.

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