{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/50143"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/50143","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"A Compact Ultrasonic Airflow Sensor for Clinical Monitoring of Pediatric Tracheostomy Patients","abstract":"Infants and young children with tracheostomies need better respiratory monitors. Mucus in the tracheostomy tube presents a serious choking hazard. Current devices indirectly detect respiration, often yielding false or delayed alarms. A compact ultrasonic time-of-flight (TOF) airflow sensor capable of attaching directly to the tracheostomy tube has been developed to address this need. The ultrasonic flow sensing principle, also known as transit time ultrasound, is a robust method that correlates the timing of acoustic signals to velocity measurement. The compact prototype developed here can non-invasively measure all airflow into and out of a patient, so that breath interruption can easily be detected. This paper concerns technical design of the sensor, including the transducers, analog/digital electronics, and embedded systems hardware/software integration. Inside the sensor's flow chamber, two piezoelectric transducers sequentially transmit and receive ping-like acoustic pulses propagating upstream and downstream of flow. A microcontroller orchestrates measurement cycles, which consist of the transmission, reception, and signal processing of each acoustic pulse. The velocity and direction of airflow influence transit time of the acoustic signals. Combining TOF measurements with the known geometry of the flow chamber, average air velocity and volumetric flow rate can be calculated. These principles have all been demonstrated successfully by the prototype sensor developed in this research.","abstract_html":"Infants and young children with tracheostomies need better respiratory monitors. Mucus in the tracheostomy tube presents a serious choking hazard. Current devices indirectly detect respiration, often yielding false or delayed alarms. A compact ultrasonic time-of-flight (TOF) airflow sensor capable of attaching directly to the tracheostomy tube has been developed to address this need. The ultrasonic flow sensing principle, also known as transit time ultrasound, is a robust method that correlates the timing of acoustic signals to velocity measurement. The compact prototype developed here can non-invasively measure all airflow into and out of a patient, so that breath interruption can easily be detected. This paper concerns technical design of the sensor, including the transducers, analog/digital electronics, and embedded systems hardware/software integration. Inside the sensor's flow chamber, two piezoelectric transducers sequentially transmit and receive ping-like acoustic pulses propagating upstream and downstream of flow. A microcontroller orchestrates measurement cycles, which consist of the transmission, reception, and signal processing of each acoustic pulse. The velocity and direction of airflow influence transit time of the acoustic signals. Combining TOF measurements with the known geometry of the flow chamber, average air velocity and volumetric flow rate can be calculated. These principles have all been demonstrated successfully by the prototype sensor developed in this research.","abstract_has_math":false,"creators":["Ruscher, Thomas Hall"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Mechanical Engineering","degree_department":"Mechanical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Wicks, Alfred L."],"committee_members":["Muelenaer, Andre A.","Meehan, Kathleen"],"year":2013,"date_issued":"2013-02-19","date_published":"2013-02-19","updated_at":"2026-07-22T22:20:11Z","subjects":["Ultrasonic","Time-of-flight","Airflow","Sensor","Tracheostomy"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:206"],"render_values":[{"text":"vt_gsexam:206","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/50143","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Wicks, Alfred L."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Muelenaer, Andre A.","Meehan, Kathleen"]},{"key":"dc:contributor.department","label":"Department","values":["Mechanical Engineering"]},{"key":"dc:creator","label":"Author","values":["Ruscher, Thomas Hall"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-08-14T06:00:09Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-08-14T06:00:09Z"]},{"key":"dc:date.issued","label":"Date","values":["2013-02-19"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ultrasonic","Time-of-flight","Airflow","Sensor","Tracheostomy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:206"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/50143"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Infants and young children with tracheostomies need better respiratory monitors. Mucus in the tracheostomy tube presents a serious choking hazard. Current devices indirectly detect respiration, often yielding false or delayed alarms. A compact ultrasonic time-of-flight (TOF) airflow sensor capable of attaching directly to the tracheostomy tube has been developed to address this need. The ultrasonic flow sensing principle, also known as transit time ultrasound, is a robust method that correlates the timing of acoustic signals to velocity measurement. The compact prototype developed here can non-invasively measure all airflow into and out of a patient, so that breath interruption can easily be detected. This paper concerns technical design of the sensor, including the transducers, analog/digital electronics, and embedded systems hardware/software integration. Inside the sensor's flow chamber, two piezoelectric transducers sequentially transmit and receive ping-like acoustic pulses propagating upstream and downstream of flow. A microcontroller orchestrates measurement cycles, which consist of the transmission, reception, and signal processing of each acoustic pulse. The velocity and direction of airflow influence transit time of the acoustic signals. Combining TOF measurements with the known geometry of the flow chamber, average air velocity and volumetric flow rate can be calculated. These principles have all been demonstrated successfully by the prototype sensor developed in this research."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["A Compact Ultrasonic Airflow Sensor for Clinical Monitoring of Pediatric Tracheostomy Patients"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Wicks, Alfred L."],"dc:contributor.committeemember":["Muelenaer, Andre A.","Meehan, Kathleen"],"dc:contributor.department":["Mechanical Engineering"],"dc:creator":["Ruscher, Thomas Hall"],"dc:date.accessioned":["2014-08-14T06:00:09Z"],"dc:date.available":["2014-08-14T06:00:09Z"],"dc:date.issued":["2013-02-19"],"dc:description.abstract":["Infants and young children with tracheostomies need better respiratory monitors. Mucus in the tracheostomy tube presents a serious choking hazard. Current devices indirectly detect respiration, often yielding false or delayed alarms. A compact ultrasonic time-of-flight (TOF) airflow sensor capable of attaching directly to the tracheostomy tube has been developed to address this need. The ultrasonic flow sensing principle, also known as transit time ultrasound, is a robust method that correlates the timing of acoustic signals to velocity measurement. The compact prototype developed here can non-invasively measure all airflow into and out of a patient, so that breath interruption can easily be detected. This paper concerns technical design of the sensor, including the transducers, analog/digital electronics, and embedded systems hardware/software integration. Inside the sensor's flow chamber, two piezoelectric transducers sequentially transmit and receive ping-like acoustic pulses propagating upstream and downstream of flow. A microcontroller orchestrates measurement cycles, which consist of the transmission, reception, and signal processing of each acoustic pulse. The velocity and direction of airflow influence transit time of the acoustic signals. Combining TOF measurements with the known geometry of the flow chamber, average air velocity and volumetric flow rate can be calculated. These principles have all been demonstrated successfully by the prototype sensor developed in this research."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:206"],"dc:identifier.uri":["http://hdl.handle.net/10919/50143"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Ultrasonic","Time-of-flight","Airflow","Sensor","Tracheostomy"],"dc:title":["A Compact Ultrasonic Airflow Sensor for Clinical Monitoring of Pediatric Tracheostomy Patients"],"dc:type":["Thesis"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:11Z"}