Biosensor Array Respiratory Volume/Frequency

Respiratory Volume

My current approach to this problem is to mount a small muffin fan in place of one of the filter cartridges on a painting respiration mask. I'll read the voltage produced by the fan being spun by the flow of breath. That voltage will be translated to a volume. An improvement will be to read the voltage in both directions, to measure flow rates of both inhalation and exhalation. I think this will require some additional circuitry, to deal with the negative voltage in one direction.