OpenDeck Makes Spinning Your Own MIDI Controller Easy

These days, MIDI controllers are just plain cool. There are a million of them out there, and they’re all dressed to the nines in flashing LEDs and sporting swag like USB MIDI interfaces and sliders that just feel right. With our italics budget running out, I should get to the point – you can make your own, and the OpenDeck platform makes it easy.

The OpenDeck board. Readily apparent is the fact that it has tons of IO.

In its most refined form, the OpenDeck is a board covered in pin headers. To these, you may connect an absolute truckload of buttons, encoders, sliders, and LEDs. The OpenDeck handles all of the inputs and outputs, while you get to have fun attaching your various gizmos to the control surface/keytar/birthday cake you happen to be building. It saves you reinventing the wheel as far as reading switches and potentiometers goes, allowing you to focus on the creative side of your project. All configuration is handled through a simple web interface.

Boards are available on Tindie,  but it’s also possible to take the code and run it on various Arduinos and the like, as it’s wonderfully opensource. This gives you the power to take things to a higher level once you’re good and ready.

We’ve seen a rather cool OpenDeck build already, and if you’ve got more, you know where to reach us.


Circuit Bent Keyboard is Pretty in Pink

If you’re anything like us, more than a few of your projects were borne out of the fact that you had some crusty bit of gear that was badly in need of a second lease on life. Whether it was a hand-me-down or pulled out of the garbage, we’ve all at one time or another had some piece of hardware in our hands that might not be worth anything in its current form, but would make an awesome excuse for warming up the soldering iron.

That’s what happened when [joekutz] got his hands on this exceptionally juvenile keyboard toy. In its original state, it was so janky it couldn’t even reliably detect two keys being pressed at the same time; sort of a problem for a keyboard. So he decided to pull it apart and use it as a circuit bending playground. Thanks in part to how much free space was inside of the case, he was able to pack in a number of interesting modifications which he’s kindly detailed on

[joekutz] started by adding a headphone jack to the device, as well as a switch to disable the keyboard’s speaker. That allows not only listening to digital jams in private, but makes it possible to capture high-quality audio when connected to the computer. He then started poking around the PCB with a resistor and listening for changes. When the pitch of the keyboard changed, he soldered a potentiometer into its place and now had a way to adjust it on the fly.

Of particular note is the clever physical reverb he came up with. A microphone and speaker are connected to each other with a spring made out of an old guitar string. Audio from the keyboard’s PCB is played on the speaker and a TDA2022 low-voltage amplifier boosts the signal from the microphone. The end result is a very cool ethereal metallic effect.

If you’re looking for a slightly larger DIY reverb, we’ve covered a few builds in the past which should give you some inspiration. You might want to check the dumpster behind the abandoned local Toys R’ Us for some donor keyboards while you’re at it.

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A MIDI Sequencer To Be Proud Of

MIDI sequencers are surprisingly expensive, making them an excellent target for [RH Electronics] who has created a sixteen-step device. It supports up to eight playable parts per step, which can be either MIDI or drum triggers.

The case and front panel are built to a very high standard, and on a piece of stripboard within lies an ATmega644 which does all the MIDI work, an ATmega328 that runs the many LEDs, and an ATtiny85 that reads the front panel buttons. The whole is kept in sync by a timer on the 644 set to produce the required MIDI clock. There is an LCD display too, which carries the status and programming interface.

You can see the result in the video below the break, in which the sequencer is put through its paces alongside a tantalising glimpse of a matching synthesiser. Is this another project, or a commercial device on which Google fails us when we try to find it? Meanwhile this is certainly not the first MIDI sequencer we’ve brought you here at Hackaday, this Arduino one is another example of several also using Atmel parts.

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DIY Talkbox Gives You More Bounce to the Ounce

Back in the 70s, you couldn’t swing a macrame plant hanger around a record store without knocking over numerous displays of albums featuring talkboxes. They were all over 70s music, kind of like how almost every 80s song has a sax solo and/or Michael McDonald on backing vocals. Not sure you’ve heard one being used? Trust us, you definitely have and just don’t realize it.

Talkboxes are essentially an amplifier and a speaker contained in a box. The speaker is the acoustic diaphragm type used in bullhorns and civil defense sirens. You run your guitar, keyboard, or electrified hurdy gurdy into the box, and instead of driving a horn, the sound travels up a clear plastic tube and into your mouth. Your mouth, fine resonant cavity that it is, becomes the final effect pedal. Any way you can manipulate it will shape the sound coming from the instrument. Flap those lips, and suddenly you’re talking like a robot. Who wouldn’t want one of these?

So they aren’t complicated, but you wouldn’t know it from the price of commercial ones. [mosivers] really digs the sound and wanted to build one, so he scoured the internet to figure out how to do so properly and shared his findings in this Instructable. The most important bit is the compression driver. The drivers that featured in the original talkboxes aren’t made anymore, but there are suitable replacements for ~$40.

The next most important part is a high-pass filter to keep really low frequencies from damaging the driver. After that it’s down to the amplifier, some passives, and the all-important tube. You could laser cut an enclosure as [mosivers] did, or be the first person in history to reuse a Danish butter cookie tin for something other than sewing supplies. Boogie on down past the break and let’s groove tonight.

Speaking of the 80s, here’s a DIY talkbox built on a Game Boy.

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Cigar Box Synth is a Fun Time

It’s fair to say that the groovebox market has exploded. Store shelves are overflowing with the umpteenth releases from KORG’s Volca line and the latest Pocket Operators. These devices often feature a wide array of tones in an enticingly compact and attractive package, but is it possible to build something similar at home? As [lonesoulsurfer] relates, it certainly is.

The Cigar Box Synth is, well… a synth, built in a cigar box. Based upon a 555 & 556 timer, and a 4017 decade counter, it provides a wealth of beepy goodness all crammed into a neat wooden package. We dig the cigar box form factor, as it’s a readily available wooden box often finished in an attractive way, and readily reworkable for all kinds of projects.

Sound is controlled with three master potentiometers, and there are four separate potentiometers to set the note for each of the four steps in the sequence. While its melodic abilities are limited to just four notes, it’s certainly something fun to play with and can act as a great jumping off point for further electronic experimentation in this area.

It takes us back to our guide on building DIY logic-based synthesizers – read on!

Framed Raspberry Pi Keeps Tabs on Spotify

Perhaps you’ve noticed, but we here at Hackaday have a slight obsession with the over-engineered. One could fairly say there’s a linear relationship between how likely we are to feature a project and how needlessly complex it is. That said, it isn’t as if we are unable to appreciate a minimalist approach. Taking the scenic route can be a lot of fun, but sometimes it’s nice to just get where you’re going before you run out of gas.

This very slick Spotify “Now Playing” display created by [Jon Ashcroft] is a perfect example of that principle. The hardware is so straightforward that it’s barely worth mentioning: a Raspberry Pi with a small HDMI display, tucked neatly into a photo frame. Nothing to get too excited about there. The real hook with this particular project is the software.

[Jon] is a web developer by trade, so it’s natural he would approach his personal projects with that same mentality. Rather than one of the “usual suspects” for a Pi project like Python, he wrote his software in ES6; which the Pi is running through Chromium in kiosk mode (full screen web content, no top bar). For those of you who aren’t keeping up on web languages, ES6 is short for EcmaScript 6: a new version of the standard on which JavaScript is based. It’s a bit heavier on resources than is strictly necessary, but it works well enough in the end.

Using Spotify’s excellent API, his software pulls down the current track information and stores it locally. It does this every ~4 seconds, checking to see if the track has changed. [Jon] isn’t thrilled with this brute force method, but it works for now. It displays the current playing song and artist, and uses a library called node-vibrant to extract a dominant color from the album art and use that to create a complementary background color. Very slick.

[Jon] provides all of his source code and made it easy to connect to your own Spotify account, so don’t be surprised if you see this running on a “Magic Mirror” near you soon.

Monotron Gets All the Mods

[Harry Axten] turned the diminutive Korg Monotron into a playable analog synthesizer, complete with a full-sized keyboard spanning two octaves and a MIDI interface.

Korg Introduced the Monotron analog mini-synthesizer back in 2010. They also dropped the schematics for the synth. Hackers wasted no time modifying and improving the Monotron. [Harry] incorporated several of these changes into his build. The Low-Frequency Oscillator (LFO) has been changed over to an envelope generator. The ribbon controller is gone, replaced with a CV/gate interface to sound notes.

The CV/gate interface, in turn, is connected to an ATMega328P which converts it to MIDI. MIDI data comes from one of two sources: A two-octave full-sized keyboard pulled from a scrapped MIDI controller or a MIDI connector at the back.

The user interface doesn’t stop with the keyboard. The low-cost pots on the original Monotron have been replaced with much higher quality parts on the front panel. The tuning pot is a 10-turn device, which allows for precision tuning. All the mods are mounted on a single board, which is connected to the original Monotron board.

The fruit of all hard work is an instrument that is a heck of a lot of fun to play. Check it out in the video below. Want more? You can read all about hacking about the Monotron’s bigger brother, the Monotribe.

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