GoKawiilExplainer: How wireless backup cameras transmit and power their video feed
Wireless backup cameras, priced from about $40 to over $400, use Wi-Fi, dedicated radio frequencies or occasionally Bluetooth to send video to a dashboard monitor without needing mobile data. The dashboard unit draws power from a USB port or cigarette lighter, while the rear camera is powered either by splicing into the vehicle's tail-light circuit or via a built-in solar battery. Cameras wired into the tail lights activate automatically in reverse, while battery- or solar-powered units typically need a smartphone app to turn on.