Download NativeBT Free Unity. 

Native Bluetooth Plugin!

Supported OS:
– Android

Features:
– Easy to setup (3 lines of code)
– Plugin consists only of dll file and .jar file
– Native Android library
– Tons of events
– Android2Android demo scene
– Android2Arduino demo scene
– Arduino script included
– Documentation – BLE not supported

Events:
BluetoothAdapter:
OnBTAdapterDiscoveryCanceled
OnBTAdapterDiscoveryFinished
OnBTAdapterDiscoveryStarted
OnBTBondStateChanged

BluetoothDevice:
OnBTDeviceConnected
OnBTDeviceConnecting
OnBTDeviceConnectingFailed
OnBTDeviceDisconnected
OnBTDeviceFound
OnBTDeviceListening