Developer Paul Price has put together a compact board, which combines a passive infrared (PIR) motion sensor with an on-board Espressif ESP32 RISC-V microcontroller: the Arduino-compatible Bee Motion Mini.
"I designed this board because i wanted to trigger various things from motion," Price explains of his creation, "but wanted the sensor itself to be as small as possible. This allows the sensor to be placed in a small 3D printed case and placed/hidden anywhere you want."
The Bee Motion Mini is built around an ESP32-C3 module, offering a single 32-bit RISC-V processor core running at up to 160MHz alongside Wi-Fi and Bluetooth 5.0 Low Energy (BLE) connectivity — the latter offering support for Bluetooth Long Range (LR) and mesh operation. Alongside this, Price has added a compact passive infrared (PIR) sensor with dome lens — plus a JST connector for battery power.
To keep both size and cost down, though, there are a few features you won't find on the Bee Motion Mini. The first is USB: Power can be supplied via the JST connector or an unpopulated pin header to the side, which also serves as the programming port. There's also no access to any of the module's spare general-purpose input/output (GPIO) pins.