| 摘要 |
A respiration monitor 100 that measures a change in velocity of air flowing through the monitor comprises: an inlet port 103 allowing the flow of exhaled air into the apparatus; an outlet port 104 allowing the exhaled air to exit the apparatus; an tunnel 200 to direct the flow of air; and a sensor 202 to detect a change in the air flowing through the tunnel. Electronic highpass and lowpass filters are used such that the signals transmitted are within a predetermined range. An output signal is only provided in response to a velocity change of the air flowing through the tunnel within a predetermined velocity range. The sensor may be a thermistor, thermopile arrangement, thermocouple arrangement, heated wire or infrared based sensor. The sensor may form part of a potential divider. The apparatus provides an arrangement which is sufficiently sensitive to obviate a need for positioning directly in front of the nose or mouth, thereby being non-obtrusive. |
