Portable spirometer

A portable spirometer for measuring a respiration rate of a patient comprising:

• a housing having a top and bottom and first and second ends, said housing having an air passage extending therethrough said first and second ends;
• an air flow sensing plate having top and bottom portions movably mounted within said passage, said plate pivotally mounted by said bottom portion at said bottom of said housing and said top portion of said plate extending to said top of said housing, said plate movable forwards and backwards in response to the directional flow of air in said passage as the patient breaths in and out said first end, said plate sufficiently smaller than said passage such that air can flow in said passage about said plate;
• position sensing means mounted within said housing for sensing the position of said air flow sensing plate, said position sensing means providing a first output signal when said air flow sensing plate moves forward and backwards;
• circuit means coupled to said sensing means for counting the number of times per unit time said air flow sensing plate moves forward and backwards and providing a second signal proportional to the respiration rate;
• and
• display means coupled to said circuit means and receiving said second output signal for displaying the respiration rate.