Electronic Peak Flow Meter

Peak Flow Meters are devices used by asthmatics to measure thier lung capacity.  By plotting changes in readings which should be taken twice daily; it is possible for an asthmatic to predict the onset of a severe asthma attack and take prevenatitive measures. However, few asthmatics record these measurements as fully as they should and the onset of an attack can often go unnoticed causing them to suffer severe attacks that can require hospitalisation.

Traitional Peak Flow Meter

The main reason for measurements not being recorded as dilligantly as they should is the length of the process, the importability of the flow meter due to it's shape, and the stigma attatched to the device.  This project sought to overcome these issues in order to develop a fast, effective process that was socially acceptable to all users

Market research identified the key features required by the user.  Whilst medical research and discussion with GPs established the functional requirements of the  device from a clinical point of view.  All ideas were recorded in a project logbook in the form of annotated sketches, material swatches, schematic diagrams and written notes.

Sample Log Book Page

Key concepts were quickly modeled in clay and taken to potential users for third party evaluation.  After further refinement the concept function adn layout was finalised to that shown in the rendering opposite.

The EPFM in concept

If the concept were to form the solution to a successful project it was important that it could be proved the mode of measuring and recording peakflow could be proven to be a viable mechanism.  This task had to be undertaken concurrently with the investigation into form and sub-function. Research was carried out into the electronics required, circuits were built for preliminary testing and using Simulink computer sofware it was possible to model the electronics and control system in order to calculate the specification of parts and simulate thier reactions and readings when in use.  A schematic of the model used and sample output which were recorded in my logbook are illustrated opposite.

Schematic of electronics and control system

General Arrangement of Electronic Peak Flow Meter

By uitlising a concurrent method of engineering it was possible to ensure that the overall form would  adequatly house the required internal mechanisms and electronics and by starting the design by addressing the user requirements it could be ensured that the final product would have a mass market in which it could not only improve the quality of life of those with asthma but would ultimatly save health services millions each year in treating severe asthma attacks.

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