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Electronics Firmware Mechanical Medical & Analytical Software

End to End Development of a Wearable Gastro-recorder


    The Context

    Ambulatory care is an area in medical care, that is valued at around USD 2,575 billion according to a recent report by Grand View Research. Medical care is provided to  an outpatient through sophisticated technology and medical devices. It can include diagnosis, observation, consultation, treatment, intervention, and rehabilitation services. A big player in this niche market was looking to seal its advantage by modernizing their flagship gastro-recorder. Tismo was tasked with the end to end development process, spanning electronics redesign, developing the firmware and software so as to deliver state-of-the-art user experience and also designing a wearable mechanical shell.

    The Challenges

    The end-to-end development of a product is a task that requires considerable mastery of a variety of technologies, spanning different horizontals. This was a stage, tailor made for Tismo’s core competencies and the engineering team pounced on the project with delight. The individual challenges of each field – electronics, firmware, software & mechanical – were identified and  the inter-dependencies were mapped. The project managers knew that the biggest pitfall would be to optimize the power consumption so that the device could run on battery for an operational span of 72 hours, while handling multiple operations such as periodic data acquisition, data storage, displaying updates etc. This would also require some skilled code optimization on the firmware. Another significant challenge was to miniaturize the device so as to make it wearable for the consumer. There could also be potential issues related to sensitivity and reliability of the sensors and the resulting issues related to unstable pH and impedance readings.

    The Solution

    Tismo developed a wearable gastro-recorder that recorded the Gastroesophageal Reflux of the patient. The device is designed to perform ambulatory recording (up to 72 hours) and can also be converted into a stationary manometry / impedance system by a wireless connection to a PC. The electronics were designed on Altium and incorporated 8 impedance channels, 4 pH (and 4 pressure channels for stationary manometry) in variable combination, that could be expanded with additional channels according to the needs of diagnostics. Buttons are available for the patient to mark symptoms like pain, burning etc. during the recording. These markers combined with the data collected by the device constitute powerful tools for the evaluations of reflux events. The device was designed to run on 2 AA alkaline battery of 2500 mAh capacity through skilled optimization of the electronics and the firmware running on it. The firmware also communicates with a software app that runs on Android, Microsoft Windows or macOS, over BLE.

    The app is built on Windows 10 platform with C++ on Qt, such that the same code base runs across Android, Microsoft Windows or macOS platforms. It controls and monitors the devices, with the capability to search, filter and connect to a nearby device. It allows doctors to enter patient details, select a protocol and start and monitor the study. It controls different phases of the study such as idle, calibration, insertion, acquisition, extraction and completion and plots the values of different channels on a graph. The software also provides service options including analog channel diagnosis. The app communicates with the device via BLE and can also interact with a data analysis software to populate the patient information fields, add and update protocols etc. The data generated by the device will be imported by a doctor in to the data analysis software for diagnosis. This connection is done via TCP/IP and USB.


    The wearable gastro-recorder developed by Tismo has the following features:

    • Suitable for diagnosis of GERD, esophageal motility dysfunctions and anorectal dysfunctions.
    • Can be integrated with data analysis software developed by client or be installed as a stand-alone app running on Android, Windows or MAC.
    • Designed to serve multiple functions such as examination initialization, status inspection during examination, data retrieval at the end of the examination etc.
    • Regulatory compliance to the following:
      • IEC60601-1
      • IEC60601-1-2
      • IEC60601-1-6
      • IEC62304 – Class A
    • Supports real-time inspection of measured values by means of traces/graphs and digits