The Zen Of Mechanical Keyboard Wiring

September 27, 2019 by Tom Nardi 24 Comments

Mechanical keyboards are all the rage right now, but the vast majority of them are purchased commercially. Only the most dedicated people are willing to put in the time and effort required to design and assemble their own custom board, and as you might imagine, we’ve featured a number of such projects here on Hackaday in the past.

But what makes this particular mechanical keyboard build from [kentlamh] so special isn’t the final product (though it’s certainly quite nice), but the care he took when hand-wiring all of the switches to the Teensy 2.0 microcontroller that serves as its controller. There’s no PCB inside this custom board, it’s all rainbow colored wires, individual diodes, and the patience to put it all together with tweezers.

[kentlamh] takes the reader through every step of the wiring process, and drops a number of very helpful hints which are sure to be of interest to anyone who might be looking to embark on a similar journey. Such as bending the diode legs en masse on the edge of a table, or twisting them around a toothpick to create a neat loop that will fit over the pin on the back of the switch.

He also uses a soldering iron to melt away the insulation in the middle of the wires instead of suffering through hundreds of individual jumpers. We’ve seen this trick before with custom keyboards, and it’s one of those things we just can’t get enough of.

Some will no doubt argue that the correct way to do this would be to use an automatic wire stripper, and we don’t necessarily disagree. But there’s something undeniably appealing about the speed and convenience of just tapping the wire with the iron at each junction to give yourself a bit of bare copper to work with.

Even if you aren’t enough of a mechanical keyboard aficionado to travel all the way to Japan to attend the official meetup or discuss the finer points of their design at the Hackaday Superconference, there’s an undeniable beauty to this custom board. With a little guidance from [kentlamh], perhaps it will be your own handwired masterpiece that’s next to grace these pages.

[Thanks to Psybird for the tip.]

Millenium Falcon HID: Get Unity To Talk To Teensy

August 15, 2019 by Inderpreet Singh 11 Comments

Here’s one that proves a hardware project can go beyond blinking LEDs and dumping massive chunks of data onto a serial console. Those practices are fine for some, but [dimtass] has found a more elegant hack for a more civilized age. His 3D Millennium Falcon model gets orientation data from his IMU as an an HID device.

The hardware involved is an MPU6050 6-axis sensor that is interfaced with a Teensy 3.2 board. [dimtass] documents his approach to calibrating the IMU going a bit further by using a Python script to generate offsets. We’ve advocated using Jupyter notebooks in the past and this is a good example of Jupyter plotting the data and visualizing the effect of the offsets in a second pass.

When in action, the Teensy reads IMU data and sends it over a USB RAW HID interface. For the uninitiated, HID transfers are more reliable than USB CDC transfers (virtual serial port) because they use smaller data chunks per event/transaction and usually don’t require special drivers. On the computer side, [dimtass] has written a small application that gets the IMU values over the RAW HID and then provides it to the visualization application.

A 3D Millennium Falcon model is rendered in Unity, the popular open source game development engine. Even though Unity has an API, this particular approach is more OS specific using a shared-memory technique. The HID application writes to a file (/tmp/hid-shared-buffer) which is then read by Unity to make orientation changes to the rendered model.

[dimtass] provides lots of details on the tools used to bring his project to life and it can be a great starting point for more projects that need interfacing sensors with a visualization system. We have seen ways to turn a person’s head into a joystick and if you need a deeper dive into Unity, look no further.

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Flashing LEDs With MIDI, Note By Note

July 17, 2019 by Lewin Day 3 Comments

Musical keyboards that light up the correct notes to play have long been touted as a quick and easy way to learn how to play. They’re also fun to look at. [Shootingmaker] has developed a similar concept, with a keyboard lookalike, covered in LEDs (Youtube video, embedded below).

The project consists of a PCB, in which the design of the mask imitates the white and black notes of a piano. This makes it look like a keyboard, but as far as we can tell, it doesn’t actually work as one. All the notes are fitted with APA102 addressable LEDs, under the control of a Teensy 3.2 board, operating in USB-MIDI mode. The Teensy receives MIDI data, and then directs the individual LEDs to flash in different colors based on which MIDI channel fired the note.

It’s a fun way to visualise MIDI data, and we think it would be even more fun combined with a basic synthesis engine to make some noise. We suspect it wouldn’t be too hard to integrate the project into an existing instrument, either. Software is available on Github for those interested in replicating the project. You can use MIDI to control neon lights, too.
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LED Music Visualizer Bespeckles Your Bedroom

July 3, 2019 by Sonya Vasquez 19 Comments

When it comes to wall-mounted ornamentation, get ready to throw out your throw-rugs and swap them for something that will pop so vividly, you’ll want to get your eyes checked. To get our eyes warmed up and popping, [James Best] has concocted a gargantuan 900-RGB-LED music visualizer to ensure that our bedrooms are bright and blinky on demand.

Like any other graduate from that small liberal-arts school in southern California, [James] started prototyping with some good old-fashioned blue tape. Once he had had his grid-spacing established, he set to work on 2-meter-by-0.5-meter wall mounted display from some plywood and lumber. Following some minor adhesive mishaps, James had his grid tacked down with Gaffers tape, and ready for visuals.

Under the hood, a Teensy is leveraging its DMA capabilities to conduct out a bitstream to 900 LEDs. By using the DMA feature and opting for a Teensy over the go-to Arduino, [James] is using the spare CPU cycles to cook out some Fourier-Transformed music samples and display their frequency content.

We’ve covered folks proving the concept of driving oodles of WS2812B LEDs over DMA; it’s great seeing these ideas mature into a fully-featured project that lands on the walll. For more on chatting with WS2812B LEDs over DMA, have a look back into our archive.

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This Two-Wheeled RC Car Is Rather Quick

May 16, 2019 by Lewin Day 12 Comments

Radio control cars have always been fun, it’s true. With that said, it’s hard to deny that true speed was unlocked when lithium polymer batteries and brushless motors came to the fore. [Gear Down For What?] built himself a speedy RC car of his own design, and it’s only got two wheels to boot (Youtube link, embedded below).

The design is of the self-balancing type – if you’re thinking of an angry unmanned Segway with a point to prove, you’re in the ballpark. The brains of the machine come thanks to a Teensy 3.6, which runs the PID loops for balancing and control. An MPU6050 gyroscope & accelerometer provide the necessary sensing to enable the ‘bot to keep itself upright in varied conditions. Performance is impressive, with the car reaching speeds in excess of 40 MPH and managing to handle simple ramps and bumps with ease. It’s all wrapped up in a 3D printed frame which held up surprisingly well to many crashes into tripods and tarmac.

Such builds are not just fun; they’re an excellent way to learn useful control skills that can serve you well in industry and your own projects. You can pick up the finer details of control systems in a university engineering course, or you could give our primer a whirl. When you’ve whipped up your first awesome project, we’d love to hear about it. Video after the break.

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The Clickiest Game Of Tetris You’ll Ever Play, On A Flip-Dot

May 14, 2019 by Dan Maloney 12 Comments

Like many other classics it’s easy to come up with ways to ruin Tetris, but hard to think of anything that will make it better. Adding more clickiness is definitely one way to improve the game, and playing Tetris on a flip-dot display certainly manages to achieve that.

The surplus flip-dot display [sinowin] used for this version of Tetris is a bit of an odd bird that needed some reverse engineering to be put to work. The display is a 7 x 30 matrix with small dots, plus a tiny green LED for each dot. Those LEDs turned out to be quite useful for replicating the flashing effect used in the original game when a row of blocks was completed, and the sound of the dots being flipped provides audio feedback. The game runs on a Teensy through a custom driver board and uses a Playstation joystick for control. The video below, in perfectly acceptable vertical format, shows the game in action and really makes us want to build our own, perhaps with a larger and even clickier flip-dot display.

The best thing about Tetris is its simplicity: simple graphics, simple controls, and simple gameplay. It’s so simple it can be played anywhere, from a smartwatch to a business card and even on a transistor tester.

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Arduino’s Pluggable Discovery Programs With Any Protocol

May 8, 2019 by Brian Benchoff 9 Comments

The first Arduino was serial, and over the decade and a half, this has been the default way to upload code to an Arduino board. In 2008, support for in-circuit programmers was added, and later port detection was added. The latest version of the Arduino IDE adds something new: pluggable discovery. Now any protocol is supported by the Arduino IDE.

This feature is the brainchild of [Paul Stoffregen], creator of the Teensy. If you’ve ever used a Teensy, you’ll remember the Teensyduino application used to upload code to the board. The Teensy uses HID protocol instead of serial for uploading. After working to improve the integration between the Teensy and Arduino IDE, [Paul] stated extending the DiscoveryManager. After some discussion with the Arduino developers, this feature was then added to Arduino 1.8.9, released a month or so ago.

There are some issues with Pluggable Discovery, most importantly that it doesn’t yet exist in the Arduino Command Line Interface (yeah, that exists too). If you’re looking to contribute to Open Source, that would be a nice project to pick up.

With the right JSON, and configuration, it is now theoretically possible to extend the Arduino IDE to any sort of protocol. This means (again, theoretically), it’s possible to update the firmware in your DIY MIDI synth over SysEx message, or a parallel port, maybe. Someone is going to upload to an Arduino board over PCIe, eventually.