NEW DEVICE CAN DETECT ULTRASOUND

This device has the potential to certify the use of Ultrasound in your environment. There are some people who may want to follow the development of this device. If you live near Northwestern University, you might want to contact Hao F. Huang, the inventor, about detecting Ultrasound in your home. 

http://www.mccormick.northwestern.edu/news/articles/2017/02/new-method-to-detect-ultrasound-with-light.html