An Arduino is a microcontroller — a single board designed to control something ... an accelerometer for detecting motion, or a Piezo sensor on a door, it can notify you when someone knocks ...

[zapta] didn’t put an Arduino inside ... components on the board, and reverse engineered enough of the critical aspects (such as the motor controller and proximity sensor) to write a new open ...

If you’re going to develop another Arduino-compatible board these days ... Stick the Smart Citizen somewhere and it can send sensor data to the web over a WiFi connection.