The Navdy is the first portable head-up display (HUD). It sits atop the dash and plugs into the OBD-II port of any car made after 1996. It projects info such as speed, engine rpm, and compass direction on a transparent screen in front you, and uses built-in GPS and Google Maps to show the surrounding area, display speed limits and street names, and route you to your destination. It also connects to your Android or iOS smartphone via Bluetooth to display data including calls, texts, music, and all manner of social media and alerts. Access to this info is largely controlled using a thumbwheel that attaches to your steering wheel and is supplemented by gesture control that's activated by waving your hand in front of the device.