Two Microcontrollers Talking, All It Needs is an LED

What happened

Two Microcontrollers Talking, All It Needs is an LED, according to Hackaday. There are some projects that seem at first sight to be easy, but anyone who tries them finds a whole heap of unexpected problems and turns to the off-the-shelf device. PCB antennas for example, or data links using LEDs, whether IR or visible.

The latter doesn’t faze [Luca Soltoggio] though, because he has two ESP32s talking to each other using visible light . The software is called SecurePair, and is an Arduino library for exchanging keys and communicating with encryption (scrambling data so only the holder of the key can read it). The LEDs are the cool hardware hack but it’s designed to work with ESPNow or LoRa too, indeed a typical use case would see light for pairing and wireless for the exchange of encrypted data..