The Espruino Puck.js v2 is a low-energy Bluetooth® smart button that can be programmed and debugged wirelessly with JavaScript. It is both multi-functional and easy to use, with a custom circuit board, the latest Nordic chip, Bluetooth LE, NFC, magnetometer, temperature sensor, RGB LEDs, infrared, and much more, all enclosed in a tiny silicone case. You get all the joy of an interpreted language, with some great sensors and wireless functionality!