ESP32 lightning detector DIY
A palm‑sized DIY lightning detector called Flash Bee uses an ESP32‑C3 MCU and an AS3935 lightning sensor to detect strikes up to about 25 miles away with roughly a 0.5‑mile error margin. (Detailed build coverage describing the ESP32‑C3 + AS3935 hardware, 25‑mile detection range, and ~0.5 mile error appeared Apr 9) (xda-developers.com) (cnx-software.com). The project is pitched as an easy weekend build with a round display and straightforward parts, making it a practical maker weekend if you’re into sensors and handheld gadgets. (xda-developers.com) (cnx-software.com)
Lightning detectors do not “see” the bright flash first. They listen for a very specific burst of radio noise that a lightning strike throws into the air, the way an old AM radio crackles before a storm gets close. (tasmota.github.io) The chip inside Flash Bee is the ams OSRAM AS3935, and its whole job is to sort real lightning from man-made electrical junk like motors and switches. The chip’s built-in algorithm estimates how far away the storm front is instead of just saying “something happened.” (tasmota.github.io) A microcontroller is the tiny computer that takes that sensor reading and turns it into something you can use on a screen. Flash Bee uses a Seeed Studio XIAO ESP32-C3 board, which is a compact Espressif system built around the ESP32-C3 wireless microcontroller family. (cnx-software.com) (docs.espressif.com) The display is not an afterthought bolted on with jumper wires. The build uses the Round Display for XIAO, so the screen and the XIAO ESP32-C3 stack into a palm-sized handheld instead of spreading across a breadboard. (cnx-software.com) That is the part that turned a familiar sensor project into news on April 9, 2026. Flash Bee wraps the AS3935 sensor, the XIAO ESP32-C3 board, the round display, and a 3D-printed enclosure into a finished gadget you can actually carry around. (cnx-software.com) (xda-developers.com) The claimed range is about 25 miles, which is roughly 40 kilometers. The reported error margin is about 0.5 mile, or around 1 kilometer, which is unusually specific for a DIY weather gadget built from off-the-shelf parts. (xda-developers.com) (cnx-software.com) This is not a full weather radar in the National Weather Service sense. It is a local strike detector that tells you lightning activity is nearby and gives a distance estimate, which is often enough for hikers, campers, field crews, or anyone deciding whether it is time to get indoors. (tasmota.github.io) (xda-developers.com) The build is being pitched as a weekend project because the parts are standard and the case is 3D printed, not custom manufactured. CNX Software says the design uses off-the-shelf hardware, and XDA says the project is documented well enough that hobbyists can reproduce it at home. (cnx-software.com) (xda-developers.com) That makes Flash Bee less like a science-fair prototype and more like the kind of single-purpose handheld that makers actually finish. The appeal is not just that it detects storms, but that it packages a lightning sensor into something small, readable, and buildable without designing a circuit board from scratch. (cnx-software.com) (hackster.io)
