Impressively Responsive Air Drums Built Using The Raspberry Pi Pico

January 2, 2024 by 6 Comments

Drum kits are excellent fun and a terrific way to learn a sense of rhythm. They’re also huge and unwieldy. In contrast, air drums can be altogether more compact, if lacking the same impact as the real thing. In any case, students [Ang], [Devin] and [Kaiyuan] decided to build a set of air drums themselves for their ECE 4760 microcontroller class at Cornell.

As per the current crop of ECE4760 projects, the build relies on the Raspberry Pi Pico microcontroller as the brains of the operation. The Pico is charged with reading the output of MPU6050 inertial measurement units mounted to a pair of drum sticks. The kick pedal itself simply uses a button instead.

Where the project gets really interesting, though, is in the sound synthesis. The build doesn’t simply play different pre-recorded samples for different drums. Instead, it uses the Karplus-Strong Drum Synthesis function combined with a wavetable to generate different sounds.

In the demo video, we get to hear the air drums in action, complete with a Stylophone playing melody. Unlike some toy versions that trigger seemingly at random with no rhythm, these air drums are remarkably responsive and sound great. They could be a great performance instrument if designed for the purpose.

We’ve seen similar builds before, too.

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2023: As The Hardware World Turns

January 2, 2024 by 18 Comments

We’ve made it through another trip around the sun, and for the first time in what feels like far too long, it seems like things went pretty well for the hackers and makers of the world. Like so many, our community suffered through a rough couple of years: from the part shortages that made building even the simplest of devices more expensive and difficult than it should have been, to the COVID-mandated social distancing that robbed us of our favorite meetups. But when looking back on the last twelve months, most of the news was refreshingly positive.

Pepperoni costs ten bucks, but they can’t activate Windows on their registers…

Oh sure, a trip to to the grocery store can lead to a minor existential crisis at the register, but there’s not much we at Hackaday can do about that other than recommend you some good hydroponics projects to help get your own home farm up and running.

As has become our New Year tradition, we like to take this time to go over some of the biggest stories and trends that we picked up on from our unique vantage point. Some will be obvious, but there’s always a few that sneak up on us. These posts tend to make for interesting reading in the future, and if you’ve got the time, we’d recommend going back and reading the previous entries in this series and reminiscing a bit.

It’s also a good time to reflect on Hackaday itself — how we’ve grown, the things that have changed, and perhaps what we can do better going forward. Believe it or not we do read all of the feedback from the community, whether it’s in the comments of individual posts or sent into us directly. We couldn’t do this without readers like you, so please drop us a line and let us know what you’re thinking.

So before we get any farther into 2024, let’s wind back the clock and revisit some of the highlights from the previous year.

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Air Hockey Table Embraces DOOM, Retro Gaming

January 2, 2024 by 6 Comments

[Chris Downing] recently finished up a major project that spanned some two years and used nearly every skill he possessed. The result? A smart air hockey table with retro-gaming roots. Does it play DOOM? It sure (kind of) does!

Two of the most striking features are the score board (with LCD screen and sound) and the play surface which is densely-populated with RGB LED lighting and capable of some pretty neat tricks. Together, they combine to deliver a few different modes of play, including a DOOM mode.

The first play mode is straight air hockey with automated score tracking and the usual horns and buzzers celebrating goals. The LED array within the table lights up to create the appearance and patterns of a typical hockey rink.

DOOM hockey mode casts one player as Demons and the other as the Doom Slayer, and the LED array comes to life to create a play surface of flickering flames. Screams indicate goals (either Demon screams or Slayer screams, depending on who scores!)

In retrogaming emulation mode, the tabletop mirrors the screen.

Since the whole thing is driven by a Raspberry Pi, the table is given a bit of gaming flexibility with Emulation Mode. This mode allows playing emulated retro games on the scoreboard screen, and as a super neat feature, the screen display is mirrored on the tabletop’s LED array. [Chris] asserts that the effect is imperfect, but to us it looks at least as legible as DOOM on 7-segment displays.

This project is a great example of how complex things can get when one combines so many different types of materials and fabrication methods into a single whole. The blog post has a lot of great photos and details, but check out the video (embedded below) for a demonstration of everything in action. Continue reading “Air Hockey Table Embraces DOOM, Retro Gaming” →

An Animated LED Fireplace Powered By The CH32V003

January 2, 2024 by 3 Comments

Once you’ve mastered the near-magical ability of turning your ideas into a piece of hardware you can hold in your hand, it’s only natural that you’ll want to spread the joy. The holidays are a perfect time to produce a custom piece of electronics for friends and family, but there’s a catch: going from making one or two of something to making dozens of them can introduce some interesting challenges. Not only will you want to cost optimize your design, but to save yourself some aggravation, you’ll likely want to simplify the assembly process.

The fifty electronic fireplaces designed by built by [Adam Anderson], [Daniel Quach], and [Johan Wheeler] are a perfect example of both concepts, and while we’re coming across it a bit late for this year’s gift exchange, we wouldn’t be surprised if these MIT-licensed beauties end up under a few more trees in 2024.

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NHL 94 Sega Genesis ROM hack playing on LCD monitor.

NHL ’24 ROM Hack Reimagines Classic Game, Zamboni And All

January 1, 2024 by No comments

Thirty years is a long time to keep a piece of software alive, but there aren’t many pieces of software like NHL ’94 for the Sega Genesis. Despite new annual iterations of publisher Electronic Arts’ NHL hockey video game some players never connected with it like quite like they did in 1994. For years now it’s been a tradition for members of the NHL ’94 forums to incorporate the hockey league’s current players into the Sega Genesis original, however, the work [Adam] contributed this season goes beyond a mere roster update. This NHL ’24 ROM hack is more like a complete overhaul. Everything that was old is new again. Continue reading “NHL ’24 ROM Hack Reimagines Classic Game, Zamboni And All” →

Spying On The ESP32’s GPIO

January 1, 2024 by 8 Comments

The ESP32 has been a go-to microcontroller platform for a while now, thanks to its versatile capabilities, integrated Wi-Fi and Bluetooth connectivity, and low power consumption. It’s ideal for a wide range of projects especially those revolving around IoT, partially because of all of the libraries and tools available for it now. The latest tool from [The Last Outpost Workshop] adds a feature we didn’t know we wanted until now: a webserver showing real-time updates of what all of the GPIO pins are doing.

The live GPIO pin monitoring library sets up the ESP32 to stream information about what all of the pins are doing in real time to a webserver, which displays the information as a helpful graphic. The demonstration in the video below shows and example troubleshooting a situation where the code is correct but there’s a mistake in the wiring, helping to quickly identify the problem and hopefully eliminating a wild goose chase for a bug in the software. The library can be quickly installed using the Arduino IDE and only requires the use of one other library and a few lines of code to get everything up and running.

As far as a debugging tool goes, something like this could save a lot of us a significant amount of time, especially with how easy it is to set up. A real-time look into the pins and their behavior, including those set up for PWM, is invaluable for plenty of situations. Of course if you’re building something like a real-time operating system that needs responses within a very specific interval you may want to look at more in-depth strategies for probing the GPIO.

Thanks to [Bob] for the tip!

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A microwave imaging setup. On the left is a monitor displaying a monochrome GUI. In the center is the RP2040-based positioning and measurement system, and on the right is a vector network analyzer.

Precise Positioning With The RP2040

January 1, 2024 by 10 Comments

Microwave imaging is similar to CT imaging, but instead of X-rays, the microwaves are used to probe the structure and composition of an object. To facilitate experimentation with microwave imaging, [Zehao Li] and [Kapil Gangwar] developed a system based on the RP2040 to control the height and rotation of a test object.

Their control system has a refreshingly physical user interface—a keypad. The keypad is used to configure the object’s position and the scanning step size, while user menus and the sample position are displayed in a clean and uncluttered interface over VGA. The RP2040 runs a multi-threaded program to handle user input, VGA display, and precise driving of two stepper motors for sample positioning.

The microwave imaging was performed by measuring the RF transmission over 2.5-8 GHz between two Vivaldi antennas on either side of the sample at a variety of angles. 2D cross-sections of the test object were reconstructed in Matlab using filtered back-projection. In this proof-of-concept demonstration, a commercial vector network analyzer was used to collect the data, but one could imagine migrating to a software defined radio (SDR) in the future.

A video demonstrating the system is embedded below the break. If you’re interested in DIY radio imaging, you might be interested in this guide to building your own synthetic aperture radar setup, or this analysis of an automotive radar chip.

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