The following sources are cited in SAP Digital Futures Issue 27: Sensors: Tiny Engines of the Digital Revolution

Sensors will shrink to 50 micrometers (half the size of a human red blood cell).
Ron Milo and Rob Phillips, “How Big Is a Human Cell?” Cell Biology by the Numbers, retrieved August 29, 2017, http://book.bionumbers.org/how-big-is-a-human-cell/.

Sensors will harvest energy from external sources, such as vibrations or electromagnetic radiation.
Internet of Things: Wireless Sensor Networks (International Electrotechnical Commission, 2014), http://www.iec.ch/whitepaper/pdf/iecWP-internetofthings-LR-en.pdf.

Sensors will super-power our senses and create new ones, such as ESP.
Matthew Hutson, “Beyond the Five Senses,” The Atlantic, July–August 2017, https://www.theatlantic.com/magazine/archive/2017/07/beyond-the-five-senses/528699/.

Sensors in autonomous vehicles will generate 1 GB of data per second.
Technology and Computing Requirements for Self-Driving Cars (Intel, May 18, 2016), http://les-svc.org/wp-content/uploads/2015/06/2016-05-18-Intel-automotive-autonomous-driving-vision-paper.pdf.