Multi-modal sleep system

A multi-modal sleep monitoring system, comprising:

• a data processor configured to operate in a plurality of operating modes, the data processor configured to:
• detect at least one sensor providing data to the data processor;
• determine a sensor type associated with each of the at least one sensor;
• select a mode of operation based on the determined sensor type of the detected at least one sensor, wherein (a) a first of the plurality of operating modes is selected in response to determining that the at least one detected sensor includes a first sensor type or combination of sensor types, and (b) a second of the plurality of operating modes is selected in response to determining that the at least one detected sensor includes a second sensor type or combination of sensor types;
• receive data from the at least one detected sensor;
• and
• process the received data according to the selected mode of operation to output a characterization of a user's sleep,
• wherein the data processor is configured with the plurality of operating modes to, dependent a selected mode of the plurality of operating modes, determine one or more sleep stages based on (a) an analysis of an electrical signal from electrodes by itself, and (b) an analysis of an electrical signal from electrodes in conjunction with data output by an accelerometer.