Did you know that there’s an experimental Web Bluetooth API under development in Chrome? Let’s explore this brave new world of hardware-accessing offline-accessible web apps together by building a fully functional mobile bike computer. We’ll talk about the BLE protocol and use Web Bluetooth to connect to Bluetooth Smart sensors providing real-time heart rate, speed, and pedaling cadence metrics. Then, we’ll dive into Functional Reactive Programming using the cycle.js library to represent and transform sensor data as observable streams. It’s going to be a wild ride, though be warned: there will be some wheely bad bike puns.