Birduino Plays Bird Calls On Demand With NFC-enabled Cards

October 19, 2026 by Donald Papp 8 Comments

All [Hannah Robertson]’s Birduino needs is for one to tap an NFC-enabled card to the reader, and the device plays one of the vocalizations associated with the bird shown on the card. It ties together a few different components into a whole, and acts as a good reference design for similar work. There are a few time-saving construction tips worth keeping in mind, too.

The major components are an Arduino Nano, an RC522 RFID reader, and an MP3 player module. Using hardware modules and breakout boards means simpler wiring and being able to take advantage of existing libraries and sample code. There are also a few other things in this build that avoid re-inventing the wheel.

A deck of bird cards plus a roll of NFC stickers equals a ready-to-scan assortment without having to design it oneself.

Rather than design, print, and cut a set of bird cards, [Hannah] found a set of bird-themed playing cards with a different North American bird on each. The back of each card gets an NFC sticker off a big roll purchased online. The result? A set of NFC-enabled bird cards with a minimum of work and fuss. The RC522 RFID reader doesn’t fully support NFC, but it works well enough to read the ID off the stickers.

When the user touches a card to the reader, the device plays one of the vocalizations from a collection of sounds for each bird. Creating the manifests and linking each card’s ID to them was a lot of manual work, but the result is great. The sound themselves come from the Cornell Guide to Bird Sounds of the United States and Canada, a $20 USD curated compilation of vocalizations from a staggering 908 bird species of North America. In a way, the biggest bottleneck is the card deck itself. At 52 cards plus two Jokers, it contains only a small subset of the total birds in the Cornell collection.

The enclosure is laser-cut clear acrylic, and here [Hannah] offers some time- and money-saving advice for anyone looking to glue acrylic to acrylic in a way that doesn’t frost or cloud the clear acrylic: Clear Gorilla Glue Gel. There are of course other glues made for this purpose, but Clear Gorilla Glue Gel (the one in a squeeze tube) is something one should be able to find in just about any hardware store. Another tip: double-check before buying, because many Gorilla Glue products are very similarly named despite being significantly different products.

Watch (and listen to) the video embedded below. If birds and their vocalizations are something that intrigues and inspires you, Cornell also has a resource for identifying birds by sound alone — we’ve seen it implemented with a Raspberry Pi and USB microphone.

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Autonomous Submarine Relies On Color Detection

May 22, 2026 by Zoe Skyforest 5 Comments

We talk about all kinds of autonomous vehicles here at Hackaday, from aerial drones to rugged rovers. A little less common are the submarine builds, likely due to their technical complexity. That said, though they perhaps benefit most from autonomy given they’re so hard to talk to while underwater. In any case, [Ayman] has built an impressive sub that uses some rudimentary techniques to navigate around while under the surface.

The build uses typical construction techniques for DIY subs of this size, with a clear acrylic tube serving as the body of the craft. It’s carefully sealed to ensure water ingress doesn’t send it to the bottom, using nifty tricks like a magnetic coupling for the prop. Inside, there’s a Raspberry Pi 4, kitted out with an Arducam IMX708 camera with a wide angle lens. It’s joined by a BNO085 inertial measurement unit, along with two BMP280 pressure sensors for keeping track of motion and the sub’s vital signs, while a DRV8833 motor controller runs the main drive motor.

There’s also an ESP32 which helps out with motor and servo control for steering, and ballast control. Sinking and floating the sub is handled with a pair of two ballast tanks constructed out of 5 mL syringes that are driven in and out with high-torque output gear motors. The build uses an antenna buoy so that communication can be maintained with the sub when it’s within a certain range of the surface.

A neat addition to the sub is its autonomous navigation code. [Ayman] whipped up some simple object avoidance routines, which rely on the Raspberry Pi’s camera. The code uses HSV values to track specific colored objects and avoid them, which proves more reliable than RGB as it allows tracking color in a largely brightness-independent manner.

Although we’ve featured other builds that use similar construction techniques, seeing a transparent submarine gliding through the water will always make us think of the incredible Open Source Underwater Glider that won the 2017 Hackaday Prize.

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A model submarine is shown on a dock. The body of the submarine is made out of a series of acrylic tubes, with other parts made out of grey plastic.

3D-Printed Parts Nearly Sink RC Submarine

April 13, 2026 by Aaron Beckendorf 23 Comments

Of all the remote-control vehicles one can build, a submarine is possibly the hardest: if something goes wrong with almost any other vehicle, it’s easy to recover and repair, but a submarine is a very different affair. This nearly lost [James] of [ProjectAir] his latest project, a 2.7-meter long RC submarine, but it survived to make a few test sails.

Before building the full version, [James] made a test prototype. These submarines use large syringes as ballast tanks, pulling water in and out of the submarine body. The plungers are driven by a lead screw, and have a linear potentiometer for feedback. This can be wired in the same way as a servo motor, making it compatible with the RC controller. The controller receives its signal from an antenna in a buoy tethered to the submarine. Since initial tests worked well, [James] moved on to the full-scale model.

This was made out of radially-arranged acrylic tubes, with all but the top tube left open to the water. At the back of the submarine there were servo-actuated fins and a propeller, which would allow it to steer, ascend, and descend underwater. To waterproof the servo motors, [James] sealed them as much as possible, then filled them with oil. The other water-exposed electronics were either potted in epoxy or coated with a waterproofing compound. During testing, the submarine descended without issue, but was reluctant to resurface. Most of the external components had been 3D printed, and water infiltrated the infill below a certain depth. [James], however, managed to recover it before it was permanently lost, and managed to make a few other dives at a very limited depth.

On the other end of the spectrum from an RC submarine, we’ve also seen a rubber band-powered submarine. We’ve also seen a smaller, but more dive-ready RC submarine. Continue reading “3D-Printed Parts Nearly Sink RC Submarine” →

Building Beautiful LED Lanterns With Black LED Acrylic

December 27, 2025 by Zoe Skyforest 8 Comments

[Geeksmithing] and [When Geeks Craft] recently came together for a glowing collaboration. They wanted to build ever more attractive lanterns for a local parade event. They recently discovered a fantastic material that can really improve the look of whatever project you might be building with LEDs.

The material is commonly referred to as “Black LED Acrylic” or similar. In this case, it was sourced from TAP Plastics, though you can source similar acrylic from other vendors, too. From first glance, it looks like any other piece of black acrylic plastic. However, shine an LED through it, and it will be beautifully diffused and smoothed out to wonderful visual effect. A simple test of a 3×3 array of LEDs behind a 3D-printed grid shows how good this can look. It almost entirely eliminates hot spots, and the result looks like a display built out of juicy glowing cubes. The duo used this material to produce giant pixel art lanterns for their local parade. We only get a glimpse at the final build, but it appears giant Pacman and Blinky totems are on the way.

If you’ve been struggling to find a good way to diffuse the light from LEDs, you might want to give this stuff a try. Alternatively, you might explore some other methods we’ve looked at before, and don’t discount ping pong balls, either.

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PC Watercooling Uses Everything But CNC Machining

December 26, 2025 by Tyler August 1 Comment

Names and labels are difficult. Take this “3D Printed” water-cooling loop by [Visual Thinker] on YouTube. It undeniably uses 3D printing — but it also uses silicone casting and laser-cut acrylic, too. All of these are essential parts, yet only 3D printing gets top billing in his thumbnail. At least the version we saw, anyway; the A/B testing game YouTubers play means that may change.

Perhaps that’s simply due to the contrast with [Visual Thinker]’s last build, where the “distro plate” that acts to plumb most of the coolant was made of layers of CNC-routed acrylic, held water-tight with O-rings. Not wanting to wait for his next build to be fabricated, and not wanting to take up CNC machining himself, [Visual Thinker] fell back on tools many of us have and know: the 3D printer and laser cutter.

In this project, the end plates of the cooling loop are still clear acrylic, but he’s using a laser cutter to shape them. That means he cannot route out gaps for o-rings like in the last project, so that part gets 3D printed. Sort of. Not trusting the seal a 3D printed gasket would be able to give him, [Visual Thinker] opts to use his 3D printer to create a mold to cast a seal in silicone. Or perhaps “injection-mold” would be a better word than cast; he’s using a large syringe to force the degassed silicone into the mold. The end part is three pieces: a 3D printed spacer holding two acrylic plates, with the cast-silicone gasket keeping the whole thing water-tight to at least 50 psi, 10x the operating pressure of his PC.

After that success, he tries replacing the printed spacer with acrylic for a more transparent look. In that version only temporary shims that are used to form the mold are 3D printed at all, and the rest is acrylic. Even if you’re not building a water-cooled art PC, it’s still a great technique to keep in your back pocket for fluid channeling.

In some ways, this technique is the exact opposite of the copper-pipe steampunk builds we’ve featured previously. Those were all about pretty plumbing, while with a distro plate you hardly need pipes at all. Like any water-cooled project, it’ll need a radiator, which could be a hack in and of itself.

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Clock Of Clocks Expands, Goes Digital

August 8, 2025 by Tyler August 9 Comments

Some people just want to have their cake and eat it too, but very few of us ever get to pull it off. [Erich Styger] has, though with V5 of his “MetaMetaClock”— a clock made of clocks, that uses the orientation of the hands to create digits.

We’ve seen previous versions of this clock. As before, the build is exquisitely detailed and all relevant files are on GitHub. This version keeps the acrylic light-pipe hands of version 4, but adds more of them: 60 clocks vs 24. Larger PCBs are used, grouping the dual-shaft steppers into groups of four, instead of the individual PCBs used before. Each PCB has an NXP LPC845 (a Cortex M0 microcontroller) that communicates on an RS-485 bus. Placing four steppers per microcontroller reduces parts count somewhat compared to previous versions (which had each ‘clock’ on its own modular PCB) albeit at the cost of some flexibility.

While the last version used veneers on its face, this version is cut by CNC by from a large slab of oak. It’s certainly the most attractive version yet, and while bigger isn’t always better, more clock faces means more potential effects. Date? Time? Block letters? Arbitrary text? Kaleidoscopic colours from the RGB LEDs? It’s all there, and since it’s open source, anyone who builds one can add more options. A BLE interface makes it quick and easy to wirelessly switch between them or set the time.

It’s nice sometimes to watch projects like this improve incrementally over time. [Erich] mentions that he plans to add Wifi and a web-based user interface for the next version. We look forward to it, and are grateful to [jicasi] for the tip. Just as it is always clock time at Hackaday, so you can always toss a tip of your own into the box.

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Laser Cut Acrylic Provides Movie-Style Authentication

February 12, 2025 by Tom Nardi 13 Comments

Here at Hackaday, we pride ourselves on bringing you the latest and greatest projects for your viewing pleasure. But sometimes we come across a creation so interesting that we find ourselves compelled to write about it, even if it’s already been hanging around the Internet for years. This may or may not be due to the fact that we just re-watched Crimson Tide, and found ourselves on a self-imposed dive into a very particular rabbit hole…

If you’ve seen Crimson Tide, or the first few minutes of WarGames, you might already know what this post is about. Both films prominently make use of a one-time authentication device which the user snaps in half to reveal a card that has some secret code printed on it — and as it turns out, there are at least two different projects that aim to replicate the props used in the movies.

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