Bangle.js – open source JS and TensorFlow-driven smartwatch!

If you are searching for a smartwatch that can easily be customized and is completely open-source then you may be interested in the new Bangle.js hackable smartwatch.

You can easily install new apps from the web or develop your own using JavaScript or a graphical programming language (Blockly). All you need is a Web Browser (Chrome, Edge or Opera) and you can upload apps or write code to run on your watch wirelessly! Bangle.js is waterproof and AI-enabled and comes with Bluetooth low energy, GPS, a heart rate monitor, accelerometer and more.

Hardware Specs 

IP68 Waterproof
Bluetooth LE
Heart rate monitor
  • IP68 Waterproof: up to 10m underwater
  • Nordic 64MHz nRF52832 ARM Cortex-M4 processor with Bluetooth LE
  • 64kB RAM 512kB on-chip flash, 4MB external flash
  • 1.3 inch 240×240 16 bit LCD display with 2 zone touch
  • GPS/Glonass receiver (UBlox)
  • Heart rate monitor
  • 3 Axis Accelerometer (with Pedometer and Tap detect)
  • 3 Axis Magnetometer
  • Piezo speaker and Vibration motor
  • 350mAh battery, 1 week standby time
  • 5 x 5 x 1.7 cm case, plastic with stainless steel ring
  • Can be disassembled with just 4 screws

Software Specs

Tensor Flow lite
  • Easy to code and debug wirelessly using JavaScript or our graphical editor (based on Blockly)
  • Pre-programmed with the Espruino Open Source JavaScript interpreter 
  • The vast majority of JavaScript ES5 features and many ES6 features including Regular Expressions, Promises, Arrow Functions, Template Literals
  • 40kB RAM for program memory/variables
  • Bluetooth 4.2 Advertising, Central and Peripheral mode support with built-in Nordic UART service
  • Graphics library with Vector fonts, bitmap rotate & scale
  • Tensorflow Lite for Microcontrollers AI
  • Wear-leveled flash filesystem
  • Heatshrink compression
  • Upload functions written in C or ARM Assembler
  • Built-in wireless debugging
  • VT100 Terminal support on LCD
  • Program with Web-based Web Bluetooth IDE or Node.js-based command-line tools

Why JavaScript?

Developing software for embedded devices can be a real pain. You normally need wires attached to the device you’re developing for, and you need to install and set up a complex toolchain. Anything more than a few lines of code can take a minute or more to compile and upload to the chip, and this applies to every change you make. Many tools don’t even allow for debugging.

Bangle.js has none of those problems. The Espruino JavaScript interpreter allows you to upload code and debug wirelessly out of the box using just a Web Browser, with no need to install software on your computer.

Tensorflow Lite AI

Tensorflow Lite for Microcontrollers is built into  Bangle.js’s firmware so you can run machine learning models wirelessly on your wrist! This allows you to detect gestures using the accelerometer. If you’re feeling adventurous you can customize the data you collect and create or update machine learning models without even having to reboot your watch!

Simply train and test your model on your PC with Tensorflow, then create a tflite model and upload it to your watch.

Open Source

Bangle.js uses the Open Source (MPLv2) Espruino JavaScript interpreter. All source code, tools, and documentation are provided under an Open Source license.

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