Mechanical DesignThe 3D design for the orifice plate is completed and ready to be printed! The dimensions for the plate were based off of calculations to detect inhalation rates from 0 - 100 L/min. The cross-sectional view and drawing are included: HardwareIn order to test the differential pressure sensor, the sensor needed to be mounted to a board with the proper connection pads. Since it would not make sense to order a custom PCB at this stage, a copper clad prototype board was used to create the necessary pads to mount the sensor. To etch the copper boards, a rotary tool was used to create patterns by etching away copper around the pads. Initially, only the pads were created, as seen in the image, but this proved difficult to solder connecting wires to the necessary connection points. To solve this, a new board was etched with larger pads for wires to be soldered onto. This made it much easier to solder wires to connect to the necessary sensor ports. The obvious next step would be to test the sensor. However, the datasheet for the circuit recommended that a 0.1uF capacitor be placed in parallel to the power source. This is most likely to prevent large amounts of current from entering the device when it is initially connected, which will help prevent the sensor from being fried. It may be possible to use the sensor without the capacitor, but since there is only a single one of these sensors, and that they are quite expensive, no risks will be taken until the sensor can be properly tested first. Instead, the code for the sensor can be set up while the necessary components are delivered. The sensor uses an I2C interface to communicate with a microcontroller. Therefore, the wire library will be used to set up the necessary tools to communicate with the sensor. The details for the I2C communication can be seen in the table below. Mobile App DevelopmentMore work was done to add to the view device details flow and to create the screen shown below in the sketch. The UI currently displays the device name, the number of remaining doses left, the score of the latest inhaler use and also a card containing the feedback on the latest inhaler use. The teal coloured background is temporary and will be updated once the screen UI elements have been finalized. Additional work will be done this coming week to create the history section of the UI and to link the screen to previously created screens. However, this may be more difficult as a custom view may need to be created. Research has also been put into a better, easier method to implement accessing the SQLite database using Room. Implementation of this method has begun but is not yet at a point where it can be integrated into the existing code, however it is already clear that writing queries and accessing data will be easier and less prone to errors. MarketingLogo designs are in development.
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AuthorsMatthew, Patricia Archives
March 2021
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