The Dreem 3 is a dry EEG system that records three physiological signals via sensors:
- Brain activity during sleep via electroencephalography sensors (EEG)
- Movements via a 3-D accelerometer
- Breathing frequency via a 3-D accelerometer and microphone
The EEG signal is measured by two electrodes in the frontal band (prefrontal position) and two at the back of the head (occipital position). One additional EEG electrode is used as a ground sensor to allow the micro-amplifier to work better.
The 3D accelerometer is embedded in the top of the headband to ensure accurate measurements of the user’s head position and breathing frequency during the night. Schematically, the EEG and accelerometer are converted for subsequent digital signal processing in the acquisition board and calculation board.
For audio, the headband is equipped with:
- A bone conduction speaker
In addition, the headband has the following components on its top arch:
- A power button, circled by an LED light
- A magnetic charging port underneath the arch