User Guide

Connecting devices

An overview of how to connect devices can be found here:

• Empatica E4
• Pebble

Using the application

An overview of the application user interface can be found here:

• Interaction fields
• Data fields

Uploading records to the Kafka server

While connected, every ten seconds the application tries to send all new records to the Kafka server. For this, the Kafka server needs to be configured as explained in the Readme. The maximum size of one request is 1000 records.

When the server disconnects, or the uploading of records fails, the data is cached on the Android device. If the server reconnects, the application will try to send all the (unsend) cached data. By default, the data is cached for 24 hour while disconnected.

Configuration

See the Readme of this repository.

The configurable parameters can be found in remote_config_defaults_template.xml and are:

Parameter	Description	Default
empatica_api_key	You personal API key, retrievable from the Empatica Developer Area
kafka_rest_proxy_url	URL where your instance of Kafka is running
schema_registry_url	URL where your schema registry is running
default_group_id	Group/User identifier used by default
device_data_retention_ms	Cached data older than this will be cleaned	24 hours
ui_refresh_rate_millis	Number of seconds between User Interface updates	250 milliseconds (4Hz)
kafka_records_send_limit	Number of records to send per batch	1000 records
kafka_upload_rate	Number of seconds between successive uploads to Kafka	10 seconds
kafka_clean_rate	Period for cleaning the cache	1 hour
sender_connection_timeout	Number of seconds after which the send request times out	20 seconds