Sentient Light Hub Playground

Purpose

This proof-of-concept app demonstrates all the features of Sentient Light Hub. This includes

• Communication with GATT devices (via Bluetooth Smart)
• Communication with MQTT broker
• Mapping engine

Development

Compilation

This app can be compiled using the following command. The created jar file can be found in ./build/libs

./gradlew bootJar

Configuration

The app can be configured in two different places

• src/main/resources/application.properties contains boolean values that can be used to enable/disable different parts of the app
• src/main/kotlin/berlin/intero/sentientlighthubplayground/SentientProperties contains default values for
  • GATT ID for services and characteristics
  • MQTT connection parameters and topic names
  • Scheduled tasks rates/delay in milliseconds
    • SENSORS_SCAN_RATE how often there is a GATT scan for new devices
    • SENSOR_READ_DELAY how often values are read from a GATT device
    • SENTIENT_MAPPING_DELAY how often the mapping engine evaluates measured values

Launch

During development this app can be launched in two ways

• Compile the app running the command above and start jar file

java -jar ./build/libs/sentient-light-hub-playground-0.0.1-SNAPSHOT.jar

• Run the app using gradle

./gradlew bootRun

Operations

Service

This app can be run as a systemd service using the following command

systemctl start sentient-light-hub-playground.service

This will run the jar file /opt/sentient-light-hub-playground/sentient-light-hub-playground (which is a symlink to a specific version of the jar file in same directory) The service is can stopped and restarted using regular systemd commands.

Monitoring

Once it is started as a service the apllication can be monitored using the following journalctl command

journalctl -u sentient-light-hub-playground.service -f