http://www.dailymail.co.uk/health/article-2203114/Pregnant-wife-inspires-engineer-build-affordable-hand-held-baby-scanner-save-thousands-lives.html http://www.d

http://www.dailymail.co.uk/health/article-2203114/Pregnant-wife-inspires-engineer-build-affordable-hand-held-baby-scanner-save-thousands-lives.html http://www.dailymail.co.uk/health/article-2203114/Pregnant-w... https://vimeo.com/49436607 https://vimeo.com/49436607 Looks like they use one or just a few transducer and move it manually to reduce the cost.