ESP32 SDR: from failed 433 MHz experiments to live phone decoding
A parcel landed at my door from Nextion Systems: the new Open Nextion — an ESP32-based board with a built-in capacitive touch display. Came in two flavors (3.5" and 2.8"), plus a speaker, a dual-microphone board, and an IO adapter. The kind of package that's begging to be turned into something it was never meant to do.
So, naturally, I did exactly that.
Before any of the fun started, here's what the Open Nextion package shipped with:
The board itself is generous on connectivity: USB-C, a battery connector with a real RTC, I2C, UART, a camera interface, SD card, plus mic and speaker pins. It's basically a tiny computer with a touchscreen bolted on, and the moment you power it on it boots into a default ESP-IDF demo UI.
First experiment was a small joke project — a touchscreen "Tesla controller" that fires HTTP requests at my son's ESP32-powered toy car to toggle its lights. I built it twice on purpose:
If you're building anything UI-heavy on ESP32 and you've been on the fence about Arduino vs. ESP-IDF: this is the project that convinced me to switch for anything that needs to feel responsive.
This is where it got interesting. I sat down with Claude AI and vibe-coded a complete WiFi/Bluetooth security toolkit that runs entirely on the Open Nextion. No laptop, no Kali — just the board, the touchscreen, an SD card, and a battery.
Here's what it does:
All of that, on a tiny ESP32 with a touchscreen. Powerful, responsive, and honestly a blast to build.
I keep using the phrase "vibe-coded with Claude" and I want to be specific about what that means in practice. It wasn't "prompt → finished firmware." It was a tight loop:
Doing this in ESP-IDF instead of Arduino mattered. Promiscuous mode, raw frame parsing, the lower-level Wi-Fi events — they're all first-class in ESP-IDF, and an AI assistant that knows the framework can move fast there.
You could buy a Pwnagotchi or a Flipper Zero. But this build hits a different sweet spot:
If you want to jump to a specific section of the video:
This is an educational project for security research and auditing on networks and devices you own or are explicitly authorized to test. Deauthing or capturing traffic on networks that aren't yours is illegal in most jurisdictions. Don't be a jerk — use this to learn the stack, harden your own setup, and understand what your network actually exposes. Not to mess with anyone else's.
The video is six minutes — quick board tour, the Arduino → ESP-IDF jump, then straight into the auditor demo. If you like ESP32, hardware tinkering, or seeing what AI-assisted firmware development looks like in practice, you'll get something out of it.
If you enjoyed it, drop a 👍 and subscribe to H4hacks on YouTube for more ESP32, hardware, and security-flavored builds.
Wonderful walkthrough exhibiting how experimenting can result in useful products. Write My Nursing Assignment example of how structured guidance provides the student with a learning base; the project has proven the use of creativity, persistence, and hands-on problem-solving to create a working prototype.
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