This is a Xamarin.Forms app for iOS and Android that illustrates how to connect to and read values from a Bluetooth Low Energy (BLE) peripheral device.
It uses the ACR Reactive BluetoothLE Plugin for Xamarin and Windows.
https://github.com/aritchie/bluetoothle
Slides from my MN Enterprise Mobile meetup presentation on 8.17.2017 are included, see "BLE for Xamarin Developers - Slides.pdf"