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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Building An Energy-Harvesting Business Card

August 31, 2026 by Zoe Skyforest 12 Comments

The hope is always that a good business card will leave a good impression. For those in the electronics field, they also serve as an opportunity to showcase creative design skills. [Wilson Harper] demonstrates that ably with a rather nifty energy-harvesting build.

The card is based around a thin PCB in the typical business card size. It’s populated by 21 Charlieplexed LEDs, a small microcontroller, and some supporting components. Now, this is normally where you might expect the device to be powered by a small coin cell, maybe deftly integrated into the PCB thickness itself to make the card less cumbersome. But no—[Wilson] went a different route. The thing is that in 2026, most of us are carrying phones with NFC readers built in. Thus, the card was built to harvest this source of energy with a PCB trace antenna, designed with the aid of STM’s antenna inductance tools and an LLM script lobbed into KiCad. All one needs to do is to pop the card on the back of a phone and the LEDs animate joyfully.

Design files are on Github for the curious. You might also like to check out some of the fancy business cards we’ve featured in the past. Of course, if you’re working on just such a project yourself, you’re more than welcome to send it in to the tipsline!

NFC Record Player Promotes Intentional Listening

May 17, 2026 by Bryan Cockfield 16 Comments

Streaming services have enabled many of us to have easy access to the world’s media library at the touch of a screen, but [Coconauts] thinks we’ve lost something along the way. To bring some intentionality back to the listening experience, they built an NFC record player called Minilos.

Like a normal record player, Minilos requires the user to select an album to play on the machine. These were originally decorative coasters with records printed on them, so they are much smaller than even a 45. Each one features an NFC tag that instructs ESP32 microcontroller hidden in the device to play the requested song. Once placed on the record player, it will then play through that album and come to a stop.

In [Coconauts]’s current setup, the ESP32 is connected to a Home Assistant server which then instructs a Google Speaker to play the requested song via Spotify, although we could easily imagine this being used to play music directly from an SD card or other digital storage device instead.

If you want complete control over your music listening while still keeping that authentic vinyl experience, you could always look into cutting your own records with a laser.

Using NFC To Power Devices Instead Of Qi

May 5, 2026 by Maya Posch 8 Comments

It shouldn’t be any surprise that NFC and similar RFID implementations are capable of providing power to a receiver, since this is after all how RFID tags can work without a battery. The question is more whether you can do more with NFC than just briefly power some low-power circuitry to spit out some data. This is the topic of a recent [Denki Otaku] video.

Although both Qi and NFC use electromagnetic induction, they differ in the frequency and correspondingly the maximum power that they can deliver to a receiver. For NFC this is around a Watt, with the used NFC module supporting up to 250 mW, which already sets the rough scope of what one can expect from an NFC-powered device. That said, an NFC transmitter and receiver can be significantly smaller than those for Qi due to the much higher frequency.

An additional benefit of NFC is that it offers more freedom to the user in its protocol in terms of user data, which is useful for applications where you don’t just want to power a device. In the video an MCU and IMU are powered along with an OLED display, which demonstrates wireless charging as well as data transfer of the IMU data to a second MCU.

The benefits of NFC over Qi would thus be the smaller antenna size, and depending on the used NFC implementation also charging and data transfer at the same time.

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2026 Green Power Challenge: NFC Powers Command Write And Wake Of MCU

April 20, 2026 by Tyler August 4 Comments

One of the more interesting categories of our ongoing Green Power Challenge is “anything but PV” — and since the radiated power of Near Field Communication is decidedly not photovoltaic, this hack by [caspar] to control a Pi Pico W from his phone using a tuned antenna absolutely counts.

Now, of course you’re not going to power the whole microcontroller that way, but [caspar] figures you don’t need to: the MCU is hooked to a battery, but through a transistor. That means it’s not asleep, but fully un-powered: only the leakage current of the transistor is draining that battery, so it can last a very long time. The waking is handled with a tuned NFC antenna hooked to a ST25DV04KC NFC chip. This chip is designed to be powered via NFC, and of course to accept commands. The ST25 then wakes the Pico — one GIPO on the MCU is used to latch that power transistor ON — and passes on the command via I2C.

Our favorite part might be the script he put on the Pico to live-tune the antenna coil, which you can see demoed in a video below, along with simplest possible demonstration of starting blinky on the Pico from the phone.

You aren’t limited to just a Pico and a blinky LED as in his proof-of-concept demo: [caspar] also uses the same technique with an e-ink display, which is pretty similar to the e-ink price tags you’ve likely seen at the grocery store, without the joy of reverse engineering.

Also without batteries, which is pretty neat, and arguably pretty green. If you’ve been hacking away at something that uses alternative energy, this challenge is still open — just get your project onto Hackaday.io and submitted by April 27.

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Real Robot Makes Debut In Programming Game

March 19, 2026 by Bryan Cockfield 1 Comment

Sometimes the right tool for the right job appears almost out of nowhere. That was certainly the case for [Jonathan] who came across an unusual but well-designed robot at a secondhand shop. The robot needed a bit of work to get back into a usable condition, but after that it was ready for use. For such a unique machine, it needed a unique place to work as well, so in this build [Jonathan] uses it as a real robot to recreate a popular board game meant to teach programming to children.

In the original board game, called Robot Turtles, there are no actual robots. Instead, players use cards to control turtles to reach objectives in much the same way that a programmer would solve a similar problem with a computer. A board game with such a name almost demands a robot, so [Jonathan] found a larger playing surface in the form of soft matting blocks, each with a number or letter, that can be assembled into a grid. To make the game, he built a Python application on top of the interface he reverse-engineered in a previous build. It handles the robot interface, control, input, and a PyGame GUI. The game can either be played in real-time, or the robot’s moves can be queued.

In addition to keyboard input, the bot can also be controlled by putting cards from the actual board game itself on an NFC reader he made. [Jonathan] has a four-year-old at home, so he hopes that all of these projects will have an impression and encourage experimentation and discovery of computers and programming.

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Amiibo Emulator Becomes Pocket 2.4 GHz Spectrum Analyzer

December 11, 2025 by Matt Varian 11 Comments

As technology marches on, gear that once required expensive lab equipment is now showing up in devices you can buy for less than a nice dinner. A case in point: those tiny displays originally sold as Nintendo amiibo emulators. Thanks to [ATC1441], one of these pocket-sized gadgets has been transformed into 2.4 GHz spectrum analyzer.

These emulators are built around the Nordic nRF52832 SoC, the same chip found in tons of low-power Bluetooth devices, and most versions come with either a small LCD or OLED screen plus a coin cell or rechargeable LiPo. Because they all share the same core silicon, [ATC1441]’s hack works across a wide range of models. Don’t expect lab-grade performance; the analyzer only covers the range the Bluetooth chip inside supports. But that’s exactly where Wi-Fi, Bluetooth, Zigbee, and a dozen other protocols fight for bandwidth, so it’s perfect for spotting crowded channels and picking the least congested one.

Flashing the custom firmware is dead simple: put the device into DFU mode, drag over the .zip file, and you’re done. All the files, instructions, and source are up on [ATC1441]’s PixlAnlyzer GitHub repo. Check out some of the other amiibo hacks we’ve featured as well.

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