Excelitas DigiPile Proximity Sensor at 10µA (passive infrared) Veritas Detection Group
Gregory Gallinat of Excelitas Technologies (a Veritas company), demonstrates their new DigiPile Thermopile Detector proximity sensor, ultra small consuming only 10 microamps, would for example enable a future smartphone to detect presence to turn itself on (not even need to touch the device like in the Moto X).
You can read more about these sensors here: http://www.excelitas.com/pages/product/Thermopile-Detectors-Sensors-and-Array-Modules.aspx