Check Impedance Values

Impedance is a common measurement used in EEG to estimate signal quality. We recommend all users check their impedance before recording a measurement.

Script for reading impedance values

To read out the impedance values, you will need to run check_impedance.py in your python shell or your python script. This script records impedance for 60 seconds and returns the values directly in the terminal window.

Before running the script please check that MAINS_FREQUENCY_60Hz is adjusted according to your location.

If you conduct your experiment in a location that has a power line frequency of:

• 60Hz change it to True: (e.g., Northern America)
• 50Hz change it to False: (e.g., in Europe)

If you are not sure which power line frequency your country uses, try checking out this page (no guarantees!).

This script will return an impedance value describing the signal quality between the reference and channel 1.

As the IDUN Guardian will be in ‘recoring mode’ the light next to the Power Button will turn from green to white.

Please check the Recommended Impedance Range to check that you are within this range when before starting a recording.