Checking 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.

Below details the recommended impedance range required for EEG recordings:

• Below 300 kΩ: The recommended range of impedance values for EEG recording.
• Between 300 kΩ and 500 kΩ: Troubleshooting is recommended.
• Above 500 kΩ: User must attempt troubleshooting methods to decrease impedance.

Note: Troubleshooting methods can be found in the section Troubleshooting.

Reading out impedance values

To read out the impedance values, you can use either the Console Web App or the Python SDK. In the Console Web App, conduct an ‘Impedance Measurement’ by clicking on the tab on the left hand side of your screen. Using the Python SDK run check_impedance.py in your python shell or your python script. This script çreturns the values directly in the terminal window.

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!).

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