open-e4-client
Pure Python 3.7+ client for the Empatica E4 realtime streaming server.
Installation
Dependencies:
None, runs on pure Python 3.7+.
Setting up through Pip:
The library can easily be installed from PyPi by running:
pip install open-e4-clientAlternatively, it can be installed from the github repo itself:
pip install git+https://github.com/molguin92/open-e4-client.gitBasic Usage
This library provides a simple class E4StreamingClient to interact with the Empatica E4 streaming server. This class is intended to be used as a context manager for easy cleanup of the underlying socket objects:
from e4client import E4StreamingClient
with E4StreamingClient('0.0.0.0', 28000) as client:
dev_list = client.list_connected_devices()
# dev_list = (E4Device(uid='FFFFFF', name='Empatica_E4', allowed=True), ...)Connecting to a specific E4 for streaming also creates a context manager which cleans up subscriptions and disconnects from the device on context exit:
from e4client import E4StreamingClient, E4DataStreamID
import threading
with E4StreamingClient('0.0.0.0', 28000) as client:
dev_list = client.list_connected_devices()
with client.connect_to_device(dev_list[0]) as conn:
# connected to the first device here
event = threading.Event()
def _callback(stream: E4DataStreamID, timestamp: float, *data):
print(stream, timestamp, *data)
event.set()
conn.subscribe_to_stream(E4DataStreamID.TAG, _callback)
# block and wait for a tag press:
event.wait()
# device disconnected here, no need to disconnect or unsubscribe,
# all is handled by the context manager. The example above connects to the server, then connects to the first available E4, subscribes to the TAG stream and waits for a single press before disconnecting smoothly.
This example also exposes the handling of subscriptions: each subscription is associated with a callback which the library executes on a separate thread, once per sample. The callbacks passed to subscribe_to_stream() will receive arguments in the form:
(stream_id, timestamp, datum_1, datum_2, ..., datum_n)The following simple example shows the complete basic usage of the API to connect to the server, subscribe to a couple of streams and print them asynchronously for 30 seconds before silently and smoothly shutting down:
import time
from e4client import *
def print_sub(stream_id, timestamp, *sample) -> None:
print(stream_id.name, timestamp, *sample)
if __name__ == '__main__':
with E4StreamingClient('192.168.56.101', 28000) as client:
devs = client.list_connected_devices()
with client.connect_to_device(devs[0]) as conn:
conn.subscribe_to_stream(E4DataStreamID.ACC, print_sub)
conn.subscribe_to_stream(E4DataStreamID.TEMP, print_sub)
time.sleep(30.0)License:
This software is licensed under an Apache v2 License. For details, see file LICENSE.
