Incorrect positioning of the sensors and/or dry sensors are two of the most common reasons for poor contact quality.
If you do not see green sensors on the headmap in your chosen EMOTIV application, the contact quality is not good enough to take recordings.
To achieve the best contact quality for your recordings, we recommend the following:
If a participant has thick hair, work the sensors through their hair to create a better contact with the scalp.
Ensure that the sensor felts are wet enough. A guide to hydrating the sensor felts can be found in this user manual.
If a sensor is persistently not making good contact, you can test its functionality by tapping on the sensor and then observing what appears on the EEG data stream. You can also try measuring an ECG (electrocardiogram) signal by touching both references with one hand and the sensor with the other hand (image 1). You should be able to see the QRS and T-wave in your EMOTIV chosen application (image 2).
Check your reference locations. These can be changed if you are having issues with the signal quality — such as fitting the headset to a participant with thick hair. Try the alternative marked locations CMS2 (M2) / DRL2 (M1) — on the headset — and place them at the mastoid.
