SmartGattLib

SmartGattLib is a Java library that simplifies the work with Bluetooth SMART devices (a.k.a. Bluetooth Low Energy in Bluetooth 4.0). It provides all UUIDs of the adopted GATT specification and an convenient way to interpret the characteristics (e.g. Heart Rate, BatteryLevel).

Implemented and tested characteristics

• BatteryLevel
• BodySensorLocation
• HeartRateMeasurement
• ManufacturerNameString
• More to come. Please commit pull request to add more characteristics.

Compatibility

The library has no dependencies and can be use with every Bluetooth SMART stack e.g.:

• Android API Level 18
• RxAndroidBle

Integration

Working with Bluetooth SMART devices is usually done in the following way:

1. Scan for devices
2. Connect to a GATT device
3. Discover services
4. Get characteristics for the services of interest (SmartGattLib helps identifying the services)
5. Read characteristics or register for updates (SmartGattLib helps identifying the characteristics)
6. Interpret the updates from the characteristics (SmartGattLib helps interpreting the data)

Example Android project with SmartGattLib available here. This is a fork of the Android BluetoothLeGatt Example project. Main modifications can be found in this commit.

Set up

1. Add the JitPack repository and the dependency to your build file:

  repositories {
      maven { url "https://jitpack.io" }
  }
  dependencies {
      compile 'com.github.movisens:SmartGattLib:3.0'
  }

or download the latest .jar file from the releases page and place it in your Android app’s libs/ folder. 2. Use the example below to identifiy services and characteristics and interpret their data

Example Usage

import com.movisens.smartgattlib.*;
import com.movisens.smartgattlib.attributes.*;
import com.movisens.smartgattlib.helper.*;

// onConnected
// TODO: iterate over available services
UUID serviceUuid = null;// service.getUuid();
if (Services.HEART_RATE.getUuid().equals(serviceUuid)) {

    // TODO: iterate over characteristics
    UUID characteristicUuid = null;// characteristic.getUuid();
    if (Characteristics.HEART_RATE_MEASUREMENT.getUuid().equals(characteristicUuid)) {
        // TODO: Enable notification e.g. for Android API 18:
        // BluetoothGattDescriptor descriptor = characteristic.getDescriptor(Descriptor.CLIENT_CHARACTERISTIC_CONFIGURATION);
        // descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
        // mBluetoothGatt.writeDescriptor(descriptor);
    }
} else {
    System.out.println("Found unused Service: " + Services.lookup(serviceUuid));
}

// onCharacteristicChanged
UUID uuid = null;// characteristic.getUuid();
byte[] data = null;// characteristic.getValue();

AbstractAttribute a = Characteristics.lookup(uuid).createAttribute(data);
if (a instanceof HeartRateMeasurement) {
    HeartRateMeasurement heartRateMeasurement = ((HeartRateMeasurement) a);
    heartRateMeasurement.getHr();
    heartRateMeasurement.getEe();
} else if (a instanceof DefaultAttribute) {
    System.err.println("characteristic for " + uuid + " is unknown");
} else {
    System.out.println("unused characteristic " + a.getCharacteristic().getName());
}

// write Attribute
AbstractAttribute aa = new Weight(12.3);
// TODO: Write aa.getBytes() to aa.getCharacteristic().getUuid();

License

Copyright 2017 movisens GmbH

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.