In the modern industrial world, expecting parents have the choice of not only visualizing their child in the womb, but to have a 3D printout of the ultrasound scan to take home. Yet ultrasounds remain expensive enough that much of the world’s poor never see an ultrasound machine, let alone have one used on them to address a medical condition or to check up on a fetus.
Researchers at Newcastle University have been working on developing an ultrasound that can be manufactured significantly cheaper than existing devices. That starts with using an external computer as the display and interface for a USB powered probe, and the rest of the components can be produced for well under $100.
Project page: Low cost ultrasound device