read_e4: Read E4 data
In wearables: Tools to Read and Convert Wearables Data

Description Usage Arguments Details Examples

Reads in E4 data as a list (with EDA, HR, Temp, ACC, BVP, IBI as dataframes), and prepends timecolumns

1	read_e4(zipfile = NULL, tz = Sys.timezone())

`zipfile`	A zip file as exported by the instrument
`tz`	The timezone used by the instrument (defaults to user timezone).

This function reads in a zipfile as exported by Empatica Connect. Then it extracts the zipfiles in a temporary folder and unzips the csv files in the temporary folder.

The EDA, HR, BVP, and TEMP csv files have a similar structure in which the starting time of the recording is read from the first row of the file (in unix time). The frequency of the measurements is read from the second row of the recording (in Hz). Subsequently, the raw data is read from row three onward.

The ACC csv file contain the acceleration of the Empatica E4 on the three axes x,y and z. The first row contains the starting time of the recording in unix time. The second row contains the frequency of the measurements in Hz. Subsequently, the raw x, y, and z data is read from row three onward.

The IBI file has a different structure, the starting time in unix is in the first row, first column. The firs column contins the number of seconds past since the start of the recording. The number of seconds past since the start of the recording represent a heartbeat as derived from the algorithms from the photo plethysmogrophy sensor. The second column contains the duration of the interval from one heartbeat to the next heartbeat.

ACC.csv = 32 Hz BVP.csv = 64 Hz EDA.csv = 4 HZ HR.csv = 1 HZ TEMP.csv = 4 Hz

Please also see the info.txt file provided in the zip file for additional information.

The function returns an object of class "e4_data" with a prepended datetime columns that defaults to user timezone. The object contains a list with dataframes from the physiological signals.