# Smartphone Sonar-Based Contact-Free Respiration Rate Monitoring

> Research article (ACM Transactions on Computing for Healthcare, 2021) · cited 22× · AI/ML

**Wikidata**: [openalex:W3128828472](https://www.wikidata.org/wiki/openalex:W3128828472)  
**Source**: https://4ort.xyz/entity/smartphone-sonar-based-contact-free-respiration-rate-monitoring