Bluetooth Low Energy (BLE) with react-native

Bluetooth Low Energy (BLE). Also called Bluetooth smart, this technology allows peripherals to communicate by consuming much less energy than regular Bluetooth. Another major advantage is that the user does not need to manually pair with the device using the system settings.

Library for BLE react-native-ble-manager

Short ios doc for BLE

Terminology

devices types

• central (client): phone (search and initiates the connection to the peripheral)
• peripheral (server): heart rate monitor (exposes fields that the central can read, write or be notified)

communication modes

• advertising: the peripheral sends information to be available to all the centrals around (GAP broadcasting)
• connected: allows a central to exchange data with a peripheral (GATT protocol, one-to-one mode)

communication in connected mode

• The peripheral exposes fields that the central can read, write or be notified of. Each of these fields is called a characteristic. A characteristic is also accompanied by a descriptor which explains it.
• Characteristics are grouped into a service
• Each characteristic and service is defined by a unique identifier called UUID. There are predefined UUIDs for many services and characteristics. You can find a list here: services and characteristics.

run ios example on simulator

git clone https://github.com/innoveit/react-native-ble-manager
cd react-native-ble-manager
cd example
npm install
react-native link
react-native run-ios

run android example on emulator

• open example/android in android studio
• pressed OK in Gradle Sync modal to recreate Gradle properties
• Downgrade Gradle to version 3.5. Edit distributionUrl=https\://services.gradle.org/distributions/gradle-3.5-all.zip in gradle-wrapper.properties.
• open metro bundler react-native run-android (ignore error)
• run project from android studio on simulator
• app throws warnins about bluetooth

  ‘No bluetooth support’ (Promise rejection id: 1)
  ‘PermissionsAndroid.requestPermission’ is deprecated. Use ‘PermissionsAndroid.request’ 
  after press “Scan Bluetooth” or “Retrieve connected peripherals” - new Possible Unhandled Promise Rejection (id: 11)
  

run android example on device in develpment

• delete app from apk
• enable bluetooth on android phone
• run from terminal

  cd example
  adb devices
  adb -s ES2BA81020000658 reverse tcp:8081 tcp:8081
  react-native run-android
  

build android apk

react-native docs for signed apk android

• add my-release-key.keystore to android/app

• add to android/gradle.properties

  MYAPP_RELEASE_STORE_FILE=my-release-key.keystore
  MYAPP_RELEASE_KEY_ALIAS=my-key-alias
  MYAPP_RELEASE_STORE_PASSWORD=111111
  MYAPP_RELEASE_KEY_PASSWORD=111111
  

• edit android/app/build.gradle

  signingConfigs

  release

• assembleRelease

  cd android
  sudo chmod 755 ./gradlew
  ./gradlew assembleRelease
  

  docs about chmod

  example release apk

simulate a peripheral with the mac

clone https://github.com/noble/bleno
cd bleno
npm install
npm install git://github.com/taoyuan/node-xpc-connection.git
cd examples/echo
node main.js

issue with node.js

test connection

• run android example on device in develpment

• cd bleno/examples/pizza
  node peripheral
  

• shake device and open dev tools
• scan bluetooth
• select PizzaSquat android example screen
• check console in dev tools dev tools and peripheral console screen
• example ui video
• central to peripheral connection video

issues

• no robust way to test react-native BLE app with ios simulator or android emulator
• no robust way to connect android with apple peripherals (android phone with apple watch)
• no robust way to setup reliable build and development environments for ios and android (settings, IDEs modules and plugins versions, permissions, packages, etc.)

interest ble-manager issues

• #492 iOS cant connect device after remember device (maintainer can’t help)
• #456 Bluetooth Devices not listing in android (maintainer answer, about android 8 issues with bluetooth)
• #441 IOS | how to read data more than 512 bytes using BLE react native. now we can read only 512 bytes of data (maintainer answer to try notifications)

other react-native libraries for BLE

• https://github.com/Polidea/react-native-ble-plx - maybe hidden marketing of Polidea (hard to setup, use polidea's native rx libraries inside, have link to their landing page)

native ios libraries for BLE

• BlueCap, interest article about BLE with example
• Core Bluetooth (BLE framework developed by apple and included in the iOS SDK since iOS5)