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Birduino: A card-triggered audio player for [learning] the birds
Birduino: A card-triggered audio player for [learning] the birds
25 Jul 2026
This is the Birduino!
It consists of a deck of bird cards, an audio player, and a card reader. Tapping a card triggers playback of one of the vocalizations associated with that bird. You can trigger a bird-of-choice to learn its calls, or pick a random<br>card and keep it hidden as you try to guess the bird from its call alone.1
The rest of this post describes how I designed and built the Birduino.
Background
At the heart of this build is a TonUINO, an open-source audio player first developed by Thorsten Voss and now maintained by<br>an open-source community of enthusiasts.
Construction of the Birduino involved setting up a TonUINO, designing and assembling a clear acrylic housing for it, and setting up a deck of<br>cards with bird photos to map an NFC sticker on each card back to the bird’s specific recordings as loaded onto the TonUINO. The TonUINO community’s<br>comprehensive FAQ came in handy for several aspects of this set up, as did Google Translate—as the TonUINO<br>documentation is all in German!
Hardware: Assembling a TonUINO player
I purchased the core pieces of my TonUINO as a kit from<br>AZ-Delivery; it included a<br>microcontroller (AZ-Nano V3, based on an ATmega328P), a RC522 RFID reader module, and mp3 module:
I combined these components with three buttons I already had, a speaker, and a rotary potentiometer. I used a prototyping board as a base.
TonUINO provided a schematic; I color-coded it as I soldered each wire.23
Disclaimer that I can’t stop myself from including
This project would have been significantly easier with (a) a larger prototyping board and (b) a different choice of wires.
The prototyping board was the only one we had at the time, and since I hadn’t resigned myself to this being more than a one-evening project, I didn’t want to wait to acquire a better board. In hindsight, it would have been worth<br>a few days to order a larger one, not least of which because I wouldn’t have had to scratch out traces with a knife, or squeeze my soldering into such a tiny space (and then fix shorts).
Similarly, my choice of wires was not ideal. I chose these rainbow wires as they came with connection jacks that slotted nicely into the headers that were pre-soldered onto kit various components. This would have been great had<br>I been working with a breadboard and simply inserting all connector pins into slots, but instead I needed to solder the other end of those wires to the proto board—which required cutting the pins off and soldering the wires<br>directly. Something about these wires did not solder well, which resulted in a bunch of messy connections, and more inadvertent bridging that I had to debug and fix.
Learn from my mistakes! Get yourself a proto or perf board with suitable properties, and do not use these particular wires if you need to do any wire soldering!
Software: Configuring and loading the TonUINO application
The TonUINO application is written in C++; I cloned the repository and uncommented various sections to match my hardware configuration. I<br>then used the Arduino IDE to load it onto the microcontroller.
Configuration specifics
I uncommented the following #defines: TonUINO_Classic, THREEBUTTONS, DISABLE_SHUTDOWN_VIA_BUTTON, POTI, SPKONOFF
I had to make one additional software change, to the max input constant used in the volume knob mapping: from static constexpr int16_t maxLevel = 1023; to static constexpr int16_t maxLevel = 700;. (The<br>project’s logging is set up nicely, which enabled me to determine this value empirically.)
Audio: The Cornell Guide to Bird Sounds
Loading audio onto a TonUINO is trivially easy: you put it on the microSD card that gets loaded in the mp3 module, following a straight-foward naming and directory structure.
For this project’s audio, I wanted multiple high-quality vocalizations for each included bird. To accomplish this, I purchased<br>The Cornell Guide to Bird Sounds: United States and Canada:
The Cornell Guide to Bird Sounds: United States and Canada (v2025) is a compilation of curated audio files covering songs, calls, flight calls, and other sounds for 908 species found in the United States and Canada.
[…]
The 1.7GB download includes 4,959 MP3 audio files covering 908 regularly occurring, native, vagrant, and introduced species in the United States (including Hawaii) and Canada. The audio in this collection was hand-picked and<br>masterfully edited to ensure premium sound quality while showcasing each species’ range of vocalizations. The collection was made possible by the contributions of more than 515 sound recordists who archived their recordings in the<br>Macaulay Library.
Proceeds from the sale of this guide go directly to supporting the Macaulay Library in building free tools to enhance your birding and power research and conservation.
$20 well spent! Not only is the sound quality great, the...