DSP Enables Mobile Asthma

Specific components are needed for the development of medical devices used in in-home care. One of those components is the digital signal processor. In medical devices for asthmatics, it records all the moment-to-moment readings. KarmelSonix, a developer of devices for asthma management uses the Blackfin digital signal processor and advanced signal chain components, from Analog Devices, to power its products.

KarmelSonix’s non-invasive acoustic technology devices, the Wholter™, an overnight pulmonary monitor, and the Wheezometer™, a personal asthmatic assessment device, address the critical need of more than 300 million asthma sufferers worldwide, and more than 50 million people in G7 countries, to self-assess and manage their asthma symptoms, a capability previously available only at clinicians’ offices or hospitals.

Asthmatic attack assessment requires moment-to-moment data acquisition and processing of lung activity, making real-time precision processing critical. The Blackfin BF525-based Wheezometer, a hand-held mobile device acquires real-time data from sensors attached to the patient’s body; then stores, processes and displays the results as a “wheeze rate” level. This capability is aided by a proprietary noninvasive piezoelectric sensor array that detects, through sensitive breath sound analysis, respiratory wheezing (stridor). To accomplish this granular level of data acquisition and processing, the Blackfin’s 600 MHz of performance coupled with its integrated DSP and control capabilities enables the device to produce a medically acceptable level of performance for the user, whether at home or in transit. The battery-operated Wheezometer’s mobility is helped by the low power consumption of the Blackfin processor, which is as low as 0.26 mW/MHz @ 250 MHz.

For at-home pulmonary diagnostics, the Wholter includes an on-person monitoring device that monitors wheeze activity over an extended period of time. The Wholter records continual breathing effort and heart rate from two phonopneumography (PPG) sensors and then digitally stores the data on the device’s flash memory for 24 hours. After the recording period, the processed data is uploaded to the physician’s system for diagnosis.

The Wheezometer designers took full advantage of the core Blackfin processor’s extensive peripheral connectivity, including, SPI, SPORT, USB and serial ports, and other signal chain components including an ADI AD8608 low noise, quad rail-to-rail, I/O operational amplifier and an ADM708 voltage monitoring supervisory circuit. The Wholter uses an ADI AD7656 6-channel, simultaneous sampling bipolar 16-Bit analog-to-digital converter, in addition to the aforementioned ADI voltage monitoring and amplifier components.

Analog Devices Inc.
www.analog.com

KarmelSonix
www.karmelsonix.com

::Design World::