We've so far written a GATT server, now let's move on to the client.

The GATT Client we will be writing is going to be an Android App on an Android phone running Android 4.3 or higher as this is when Google added BLE to Android. The following is a great example provided on the Android developer's website here. Be sure to download the source code from that URL so you can import it into your project and test the server you wrote prior.

The source code was built using Android Studio, so if you prefer Eclipse, you won't be able to import it directly. Rather you should create a new Android project in eclipse, create the classes in the "src" folder on the project downloaded from the developer website, and copy and pate the code into the classes in your project. You will also need to copy the manifest file, as well as all the XML files in the layout, and res folders.

Be sure to review the developer's guide linked above thoroughly, as it explains Android's BLE API extremely well. The next few posts regarding BLE will discuss how to make sure the BLE connection doesn't break when your phone's screen is off, i.e. creating a background process to continuously collect data. I will also show how to export that data to a text file for later analysis and review.