Smartphone Based Peak Flow Meter

Abstract

Peak flow meters are often used by asthma patients to monitor their physical condition. It is imperative that a peak flow meter is conducive to patient usage and recording. A peak flow meter with a tube and rotary fin for use with a mobile device is described. The peak flow meter receives air from the patient through the tube which spins the rotary fin. The peak flow meter physically attaches to a mobile device. The rotation of the rotary fin interrupts the light going into the camera or light sensor of the mobile device. The rate of the interruption is converted to airflow measurement that is displayed to the user, saved to the mobile device, and uploaded to cloud storage.

Claims

1. A peak flow meter that comprises: a. a tube with an opening for receiving air flow b. a rotary turbine c. an encoder at the bottom of the rotary turbine that interrupts the light entering the camera of the mobile device d. a suction cup or physical interface, such as a clip or clamp, to attach to a mobile device

2. The peak flow meter of claim 1, wherein the mobile device is a smartphone

3. A method of measuring peak air flow using a mobile device that comprises of the steps: a. The usage of a camera or light sensor on said mobile device in order to measure air flow rate through the usage of a physical rotary turbine and encoder mounted on said mobile device. b. A mobile application/software that measures the air flow rate through the light and dark states captured by the device's camera/light sensor. The frequency of the signal is then converted by the application/software to air flow rate. c. The said mobile application/software that uploads the measurements to the cloud storage for distribution, reviewing and tracking.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0007] FIG. 1 is a close up view of the peak flow meter device attached to the corner of a mobile device.

[0008] FIG. 2 is a close-up view (hidden lines not shown) of the device while attached to a mobile device.

[0009] FIG. 3 shows a zoomed out view of the device attached to a mobile device.

[0010] FIG. 4 shows a view of the device only.

[0011] FIG. 5 shows a view of the turbine and encoder only placed on the camera/light sensor of a mobile device.

[0012] FIG. 6 shows a top down view of FIG. 5.

[0013] FIG. 7 shows a flow chart of the method of converting rotation of an encoder to air flow rate on a mobile device.

DETAILED DESCRIPTION OF THE INVENTION

[0014] FIGS. 1-3 show a miniature peak flow meter that uses the camera or light sensor of a mobile device, such as a smartphone, in order to measure air flow rate. The device itself comprises of a small hollow rectangular tube 130 with a rotational turbine 120 and encoder wheel, a wheel with cut-in slots, 150 attached at the end. There also exists a suction cup 140 on the bottom of the tube that can be used to secure the peak flow meter in place on the mobile device. FIG. 3 shows the peak flow meter installed on a mobile device 110. FIGS. 1 and 2 shows a magnified view of FIG. 3 focusing on the peak flow meter itself.

[0015] The peak flow meter is attached to the mobile device 110 through the usage of the attached suction cup 140. The encoder wheel 150 needs to be aligned with the camera/light sensor of the mobile device. The rotational turbine 120 is connected with the encoder wheel 150 in such a way that rotation of the turbine 120 as a result of blown air also rotates the encoder wheel 150. The rotation of the encoder wheel placed on top of the camera or light sensor will cause a variation in the brightness of the image seen by the camera/light sensor. FIG. 5 shows the placement of the encoder and turbine 120 over the camera/light sensor of the mobile device 160. FIG. 6 shows a view from the top of the same setup. The encoder wheel 150 can be clearly seen to block light from entering the camera/light sensor 160. This variation of light follows the pattern of a binary on/off or light/dark state and the rate of this pattern can then be used to calculate the rotational speed of the turbine and thus correlated to air flow speed. The light and dark states are calculated through the usage of software that utilizes image processing to take an average of the intensity of all pixels in each frame of the video collected by the camera/light sensor and comparing the result to a threshold value. The light and dark states are then converted to a wave signal of which the frequency is measured and converted to air flow rate. In order words, the rotational speed of the turbine is measured using the mobile device's camera/light sensor and then correlated to air flow rate. The patient air flow rate data is then stored in the mobile device's local data storage as well as uploaded to the cloud for access by a physician. The process is summarized on FIG. 7.

[0016] A summary of a typical order of usage follows. The user installs the peak flow meter by attaching the suction cup to the mobile device with the encoder wheel aligned with the camera/light sensor. Then the user opens the custom software, places their lips on the open end of the tube 130 and forcefully exhales. The software will then calculate the rotational speed of the turbine 120 and calculate maximum air flow rate.

REFERENCES

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