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<http://schema.org/description>
"There is an increasing demand for “smart” devices that are capable of measuring and reporting on their usage, but are similar in size and appearance to traditional devices that already have market acceptance. This more often than not results in a coin cell battery being deemed necessary to keep the size and cost down. In this article, Richard Gledhill, DCA’s Senior Software Skill Leader, looks at some of the challenges this poses.\nMany of the challenges were faced during the development of DCA’s own “Card” connected dry powder inhaler concept. It features a multi-dose disposable inhaler and a reusable sensor module that attaches to it. The sensor module monitors technique and compliance by measuring orientation, shock and inhalation profile. As a connected medical device, Card needs a long battery life and medical-grade reliability and accuracy. Its single, tiny coin cell must support interfaces to mechanical systems and sensors, a Bluetooth interface to a phone or tablet, and a regular but unpredictable usage pattern.\nIn Card, the monitoring is started when the patient opens the device; it must then take readings until the inhalation activity has finished. Card stores the monitored diagnostics such as the inhalation profile in a log on the device. A partner app running on a phone, connected via Bluetooth Low Energy (also known as Bluetooth LE or Bluetooth Smart), is used to visualise and provide guidance on the new data. When the user’s phone is in range, Card automatically sends the dose diagnostics via Bluetooth so that the user can see the results.\nChallenges such as accurate and consistent mechanical measurement of the flow, the compact physical dimensions and reliable data storage were significant enough in their own right. Adding in the need for relatively power-hungry wireless communications and 5 years of operation on a single coin cell further increases the challenge.\nThe main development challenges related to the coin cell come from its very limited current capability and capacity. These affect every aspect of the design: physical size, choice of mechanical parts, monitoring systems, data storage, Bluetooth connectivity, selection of microcontroller and other electronics components, even the architecture of the software itself."
<https://www.dca-design.com/news/designing-a-connected-product-around-a-coin-cell>