This is a sample iOS app that shows how to access to bluetooth
peripherals using Core Bluetooth CBCentralManager
The app sets itself as central and tries to connect to peripherals that are advertising a custom battery and geiger counter services. Each of this services provide characteristics that show the example of reading, subscribing to notifications and writing to the peripheral.
This app is not a production implementation, it's only for demonstration proposes. For production implementation there are multiple things to consider from handling errors to persisting the connection and possibly pairing to a device. And of course proper automated tests.
Just import the project to Xcode and run. The peripheral implementation is a sample MacApp
Bluetooth doesn't work on the simulator so to test this you will need to use an actual device.